tankless water heater vs standard waterheater

[HABckb]

Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.

[retiredguy123]

If your goal is to save money, you won't do it by switching to a tankless system. Just my opinion.

[villagetinker]

You will also increase the time to get hot water for your shower, etc.

On a side note, I have no idea what a tankless water heater costs, figure $200 or more for the connection, and if you are not handy the additional cost to flush (clean) the tankless water heater yearly. There was a company advertising on ToTV to replace a conventional water heater for under $900, and there was a 10% discount with the ad. I just did my own, water heater and some plumbing supplies was around $550, took 2 neighbors to help, and about 2 hours to complete the plumbing, so the $800 to $900 is not a bad price.

[Maker]

It is really nice to have a constant temperature, endless amount of hot water.

Since you are talking about electric, assuming you are installing the tankless in the same location as the tank. That would minimize the electrical costs. Also safe to ignore all the comments about how much longer it takes to get hot water with a tankless. There is no difference in output, just a difference in plumbing pipe distance.

There is a yearly flush that is beneficial to removing the scale that builds up. No anode rod to replace.

Size is measured by GPM and temperature rise.

An alternative I wish was done here is to have several smaller tankless heaters. One for master bath, one for 2nd bath, one for kitchen, and maybe one for laundry if not near one of the others. More cost, but near zero lag in getting hot water.

Operational costs should be less overall. You need the same amount of electrical energy to heat the water - maybe less because of efficiency. Need zero energy to keep a tank heated.

You will gain some space.

Check prices at big box stores, and at plumbing supply houses.

Replace the expansion tank too. Put a valve on it to make it easy to change in the future.

Many manufacturers offer a dedicated valve manifold. Get it. Makes installation so much easier, as well as performing maintenance.

While running power, try to have an outlet put in. Handy for a leak detection device. For either type replacement.

If you are hiring a plumber, check forums for recommendations. Also for people that have way overpaid for a F "happy" plumbing place.

[Toymeister]

I have a whole home energy monitor. It isolated about 14 electricity consumers, including the water heater. I also have some smart home technology with a water heater switch.

To answer the question of savings of turning the heater off on a timer due to standby costs. I left a vacant home's tanked heater on for one week, then the next i ran it for 8 hours, 16 off. I repeated the two week cycle. No one was in the home, not a gallon of water was used.

My exact savings with a timer equated to 78 cents on a monthly basis.

No, a tankless heater will not save you money.

[retiredguy123]

I have a whole home energy monitor. It isolated about 14 electricity consumers, including the water heater. I also have some smart home technology with a water heater switch.

To answer the question of savings of turning the heater off on a timer due to standby costs. I left a vacant home's tanked heater on for one week, then the next i ran it for 8 hours, 16 off. I repeated the two week cycle. No one was in the home, not a gallon of water was used.

My exact savings with a timer equated to 78 cents on a monthly basis.

No, a tankless heater will not save you money.
I knew it. Spending a lot of money upfront to try to save money over 10 years is usually not a good plan. And, don't forget the time value of money, which further reduces any potential future savings.

[HiHoSteveO]

I have a whole home energy monitor. It isolated about 14 electricity consumers, including the water heater. I also have some smart home technology with a water heater switch.

To answer the question of savings of turning the heater off on a timer due to standby costs. I left a vacant home's tanked heater on for one week, then the next i ran it for 8 hours, 16 off. I repeated the two week cycle. No one was in the home, not a gallon of water was used.

My exact savings with a timer equated to 78 cents on a monthly basis.

No, a tankless heater will not save you money.

Thanks, I was hoping you would respond!

[Arlington2]

I am considering a tankless to preclude tank failure. I have had 3 failures over the years. One was semi catastrophic with an insurance claim over ten thousand dollars to clean up and replace AC ducting, flooring and wall sections. The others were fortunately less severe, but mold was a big problem (FYI UVC in the AC really helps). A neighbor had a full catastrophic failure and ended up having to stay in a motel for over a month because the entire house was flooded. I don't know why housing codes don't require the tanks to be closer to the house exterior with a large drain. I would be interested to hear if the tankless are less prone to failure.

[UpNorth]

I am considering a tankless to preclude tank failure. I have had 3 failures over the years. One was semi catastrophic with an insurance claim over ten thousand dollars to clean up and replace AC ducting, flooring and wall sections. The others were fortunately less severe, but mold was a big problem (FYI UVC in the AC really helps). A neighbor had a full catastrophic failure and ended up having to stay in a motel for over a month because the entire house was flooded. I don't know why housing codes don't require the tanks to be closer to the house exterior with a large drain. I would be interested to hear if the tankless are less prone to failure.

Tankless heaters are typically installed outside the house, so if flooding is your concern, tankless is the way to go. Yes, it may take a bit longer for the hot water to reach a bathroom, but you likely aren't using hot water all day long. May or may not save you money, but we have been using Rinnai tankless heaters here in Florida and at our house in CT for years, and would never go back to a tank.

[CarlR33]

I knew it. Spending a lot of money upfront to try to save money over 10 years is usually not a good plan. And, don't forget the time value of money, which further reduces any potential future savings.
Yes, but it does not take into account the cost to replace a new tank after one fails as most new tanks are not lasting the usual 20 years but more like 10 or less depending on flushing schedule. I would be curious of the life expectancy of the tankless units as that could be your money savings over time. If the tankless life span is even twenty years or more you might get your return depending on how long you hold your current home. I think you need to first find out the conversion cost and work it back from there.

[biker1]

If you want to reduce the probability of a tank failure then look into Marathon water heaters. The tank is fiberglass. I had one in a previous house and would recommend them. One issue, however, is they are fairly large and the utility closet in many Villages' home may not have sufficient space. They are also a bit pricey but may be the last water heater you buy.

I am considering a tankless to preclude tank failure. I have had 3 failures over the years. One was semi catastrophic with an insurance claim over ten thousand dollars to clean up and replace AC ducting, flooring and wall sections. The others were fortunately less severe, but mold was a big problem (FYI UVC in the AC really helps). A neighbor had a full catastrophic failure and ended up having to stay in a motel for over a month because the entire house was flooded. I don't know why housing codes don't require the tanks to be closer to the house exterior with a large drain. I would be interested to hear if the tankless are less prone to failure.

[Topspinmo]

Yes, but it does not take into account the cost to replace a new tank after one fails as most new tanks are not lasting the usual 20 years but more like 10 or less depending on flushing schedule. I would be curious of the life expectancy of the tankless units as that could be your money savings over time. If the tankless life span is even twenty years or more you might get your return depending on how long you hold your current home. I think you need to first find out the conversion cost and work it back from there.

Probably in near future insurance company will force you replace it in 10 years or they won’t insure you?

[retiredguy123]

Yes, but it does not take into account the cost to replace a new tank after one fails as most new tanks are not lasting the usual 20 years but more like 10 or less depending on flushing schedule. I would be curious of the life expectancy of the tankless units as that could be your money savings over time. If the tankless life span is even twenty years or more you might get your return depending on how long you hold your current home. I think you need to first find out the conversion cost and work it back from there.
I agree, but it is almost impossible to determine the lifespan of an appliance. I have never had a tank type water heater fail, and the only one I ever replaced was more than 20 years old. I have also never done any maintenance, flushing or otherwise, on a water heater. To me, if your goal is to save money, the initial cost of an appliance is more important than speculating on how long you think something will last.

[sowtime444]

I have an EcoSmart. It is great. Saves space and I never run out of hot water. Takes up four spaces in the electrical panel though. Be aware of that.

[skippy05]

I had a home in FL with a tankless waterheater. You don't save energy and put up with several stupid things. Power out = no hot water at all. Takes a lot of wasted water flow to finally get to temp. Flow temp is never constant.

[Blackbird45]

Over 25 years ago my wife and I build an oversized home and we had an instant water heater installed.
It did live up to its name we had instant hot water through the house, but we did run into one problem.
We had also installed a large tub that should had been listed as a small pool, by the time half of it was fill the water would turn cold.
Since I do not know the first thing about instant water heaters, I can't tell you if this is a problem with all instant hot water heaters or it was the way ours was installed.
But before you go forward with this find out if there is a capacity level.

[Normal]

It may take a while to get your hot water to your faucet, but once it’s there you can have as much as you want. Shower an hour, shower 5 minutes, it doesn’t matter

[jrref]

Tankless will not save you much money because the cost of keeping water hot in a hot water tank with newer models in Florida is minimal. Also the amount of money two people use to heat hot water per year is only a couple hundred dollars. Tankless is not worth the investment unless you are building in a new house.

[eeroger]

Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.

I did some research regarding thankless, solar hybrid, and regular 50 gallon water heater. The cost benefit did not warrant the tankless heater or hybrid heater. So ... Mike Smith replaced our water heater with a new 50 gallon Rheme heater for $950 & took away the old one. We added a recirculating pump for about $450. That gives us hot water at all faucets within 4-5 seconds.

[retiredguy123]

I did some research regarding thankless, solar hybrid, and regular 50 gallon water heater. The cost benefit did not warrant the tankless heater or hybrid heater. So ... Mike Smith replaced our water heater with a new 50 gallon Rheme heater for $950 & took away the old one. We added a recirculating pump for about $450. That gives us hot water at all faucets within 4-5 seconds.
Do you mean Mike Scott Plumbing?

[GizmoWhiskers]

I used to have an 80 gal water heater. I put a timer on it so it heated from 5 AM to about 8 AM and from 5 PM to about 9 PM. It was great! Always had hot water while it turned on to heat up twice a day. I really miss having a timer.

Had an instant water heater. Hated it. 2 gallons of wasted water to reach the shower toward the back of a villa.

Now have a 40 gallon water tank in a second villa. Wish I had a timer on it. Thinking about getting quote on installation of one. Currently hot water reaches master shower in the back of the Villa within about 1 gallon of wasted water .

[biker1]

The standby losses are pretty easy to approximate. The losses are the surface area of the water heater (in sq. ft) times the temperature difference between the air outside the water heater and the water inside the water heater (in F) divided by the R-value of the water heater's insulation. This will yield BTUs/hr of heat loss.

As an example, let's assume the following:

Radius of water heater: 10 inches
Height of water heater: 50 inches
Water temperature: 120F
Air temperature: 75F
R-value of water heater's insulation: 16 (units are such to make the result come out in BTUs/hour)
BTUs per kWh: 3412
Cost of electricity: 13 cents per kWh

For this example, the standby losses should be on the order of about $24 per year.


Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.

[Priebehouse]

Probably in near future insurance company will force you replace it in 10 years or they won’t insure you?

I have already had a company refuse to quote since my tank water heater is over 12 years old.

[seecapecod]

Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.

We have Rinnai tankless hot water heaters in 2 homes in MA and absolutely plan to install one at our home in TV when the time comes! Very efficient, hot water on demand.

[seecapecod]

You will also increase the time to get hot water for your shower, etc.

On a side note, I have no idea what a tankless water heater costs, figure $200 or more for the connection, and if you are not handy the additional cost to flush (clean) the tankless water heater yearly. There was a company advertising on ToTV to replace a conventional water heater for under $900, and there was a 10% discount with the ad. I just did my own, water heater and some plumbing supplies was around $550, took 2 neighbors to help, and about 2 hours to complete the plumbing, so the $800 to $900 is not a bad price.

Not my experience with our Rinnai in MA- we’ve had 11 people in the home for a week 3 showers indoor plus an outdoor shower running and I can do dishes with hot water at the same time. No issues with it keeping up with demand.

[Black Beauty]

I did it to make more space in the garage

[Duppman]

Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.We had a licensed plumber do some work for us and asked him about tankless. His response was I would not see the payback for at least 10 years. Take his comment for what it's worth.

[dcianciolo]

Speaking of water heaters, has anyone installed a Heat Pump Water Heater? Pros / Cons?

[biker1]

I have thought about it. There are a few possible issues. The height of the unit may be a problem for some of the utility closets in the garages of homes in The Villages. If it can be installed in the utility closet in the garage, you will need to provide ventilation to the utility closet. Perhaps access to the hot air of the attic but there might be some fire code issues with that. The unit will produce condensate so you will need to tie into the condensate drain for your HVAC air handler - this shouldn't be a problem if the unit can be installed in the utility closet (where the air handler is located). There could be other issues.

Speaking of water heaters, has anyone installed a Heat Pump Water Heater? Pros / Cons?

[ron32162]

There was no maintenance for 15 years on my water tank. They last and never thought twice about it in all those years sitting in the garage. I'm just now on my second one. Why would you want to trade that for a more expensive unit ($600 + more) that takes costly yearly maintenance for a box that heats water in your garage unless your planning on showcasing it when friends and family stop by.

[PoolBrews]

I had looked into this, but decided against due to several reasons:

1) In the long run, adding up all costs, it really doesn't save any appreciable amount of money.
2) The cost of the install is equal to or greater than the cost of the heater making this a losing $$ proposition. You can't do a self install if you want a warranty. Every manufacturer requires that installation be performed by a certified electrician for a valid warranty. If you install yourself, no warranty. I'm an Electrical Engineer, and this is a simple install.

[retiredguy123]

Speaking of water heaters, has anyone installed a Heat Pump Water Heater? Pros / Cons?
Why buy something that almost no one else has, and that you may have trouble getting service or parts if it fails? The standard tank type water heater can usually be repaired or replaced the same day, so you will never be without hot water.

[RUCdaze]

I have to chime in with my two cents. I bought my pre-owned home here in late 2017. I already had a tankless heater. I have to let the water run for about 90 seconds before the hot water comes up. I've asked several professionals what I can do and they all told me there is a way to rig something up that would produce hot water faster, but it's expensive and probably not worth it. I live with the idea of wasting water everytime I need hot water.

[RRGuyNJ]

Ex Plumber here but I have been out of the game for a looong time. The tankless heater will cost a lot more up front and installation will cost more. Requires a descaling process preferable once a year. Not difficult but some people will hire out to have it done. My opinion the electric tankless heaters aren't as good as the gas units. They may have improved over the years.
Conventional water heater requires an anode rod replacement after several years. Quite often they never get replaced. Use a water tank blanket to conserve energy and a tank flush annually won't hurt and only requires a hose. In all honesty, I have never flushed my own tank. I know, "Bad Boy".
The rumor about taking longer to get water to the faucet in my opinion is simply the purging of the lines of cold water before you will feel the hot water at the faucet. If the bathroom is 30 ft from the heater it will take longer than if it's only 10 ft from the heater. Same difference with a tankless.
If you take hour long showers and run a tank dry, then and only then the tankless system would be a nice addition to the home.
Good luck!

[harby]

Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.

Tankless water heater is very expensive plus elec. work's labor. You will have to waste a large amount of water in order to get hot water, but will just save a water heater space. I installed a small instant hot water tank under the kitchen sink to save running water (my wife is not happy of seeing water running till she gets hot water). We have a gas tankless water heater...maybe save some more than elec. one. It is now 9 years old so we r not sure if we should replace with a new tankless one or regular water heater (in order to make my wife happy if we replace with a regular one)

[UpNorth]

I did it to make more space in the garage

Good reason to do so. Storage space is something we don't have enough of. Tankless gas fired Rinnai on the outside; golf clubs where the tank used to be.

[maistocars]

I did some research regarding thankless, solar hybrid, and regular 50 gallon water heater. The cost benefit did not warrant the tankless heater or hybrid heater. So ... Mike Smith replaced our water heater with a new 50 gallon Rheme heater for $950 & took away the old one. We added a recirculating pump for about $450. That gives us hot water at all faucets within 4-5 seconds.
Yes, agree. The only way to get instant hot water is with a recirculating system. We also have the Mike Scott one and it is great. We had a tankless in Texas but also had the whole house recirculating system for instant hot water. The tankless by itself will NOT give you instant hot water.

[sianagers@att.net]

We have a Flo meter attached to our tank it will monitor use and shut off if it notes a flood type situation that may occur. It’s on our tankless so unsure if can be used with the standard heaters im sure it could -brilliant invention

[Villagesgal]

I switched 10 years ago when the utility company ran a special. My savings were about 30.00 a month on my gas bill. I have never had it flushed or descaled and it's never had a problem in all these years. I'd never go back to the old big hot water tank. Call your utility, gas or electric and see if they are offering any deals or rebates. I love my tankless water heater.

[merrymini]

I only hade a tankless in a new house for about 3 years but it was gas. There is a difference between gas and electric, so you would have to find out the specifics. It is my understanding that the electric are not as good as the gas. That being said, they have come a long way in the last ten years. Endless hot water. What people do not understand is that you have to run the water, tankless or not, until the hot water reaches the fixture you are at. With the tankless, you run the hot water for about 10 seconds and turn it off, this triggers the unit on and you will not have to wait so long for the hot water to come up. Somehow, no one else but me seemed to use this technique. There is also a recirculating unit that can be added. The tankless units should last about 20 years if you take care of it and no flooding!

[Bness]

Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.

Tank heat pump water heaters may be a better solution. If your water heater is in the garage, how about an air conditioner in the garage that makes your hot water? Super efficient, probably doesn't require an electrician as it uses about the same power as your existing service. Also doesn't need to have a annual cleaning done like a tankless.
Oh and did I mention a cooler garage?

[ton80]

I have an EcoSmart. It is great. Saves space and I never run out of hot water. Takes up four spaces in the electrical panel though. Be aware of that.

I believe that Sowtime has identified a key item for consideration of replacing an electric tank water heater with a tankless electric on demand water heater. So far, no other Poster has even mentioned electric power supply as a consideration. I do not believe that you can supply enough electric power to a new on demand water to supply a whole house demand just using the using the existing electric supply to the tank system.

I am not an electrical engineer, but I will try to explain in general principles.
1. A tank system has a typical recovery rate of some 20 gal per hour.
2. A single typical shower uses 1.5 gal/ minute or 90 gal/hour. Shower water is a mix of hot and cold water and depends on the supply water temperature, the desired shower water temperature, etc. For me, a mix of 50/50 seems a good mix. So 45 gph cold and 45 gph hot. Do the math and it does not look possible using only the same electric power supply that the 20 gal per hour tank heater has currently. So the power supply needs to be at least doubled for a whole house setup. My electric panel has 2 spaces for the 220/240 v circuit to the water heater. Sowtime says he needed 4 spaces, so it is nominally double. I know that there are various sizes of breakers and wires but you can check the specifics when you are considering a specific heater.

3. IMHO the quote re Rinnai on demand water heater providing hot water for 4 showers plus other users simultaneously has to be a gas fired heater not electric. I googled Rinnai and found no electric models at all.

4. The electric on demand water heaters such as ecosmart have electric power demands of 18 and 36 kw. 18 000 watts/240 volts = 75 amps required. 36 000 watts/ 240 volts =150 amps.

5. My electric power supply panel has a 200 amp breaker but needs to supply HVAC , stoves etc, when someone wants to take a shower. IMHO, the 18kw model can be possible but not the 36 kw. You still need to check the required wiring to make sure it will be adequate or need to be replaced.

6. NG or propane fired heaters are more suited to on demand systems than electric power units.

[retiredguy123]

I believe that Sowtime has identified a key item for consideration of replacing an electric tank water heater with a tankless electric on demand water heater. So far, no other Poster has even mentioned electric power supply as a consideration. I do not believe that you can supply enough electric power to a new on demand water to supply a whole house demand just using the using the existing electric supply to the tank system.

I am not an electrical engineer, but I will try to explain in general principles.
1. A tank system has a typical recovery rate of some 20 gal per hour.
2. A single typical shower uses 1.5 gal/ minute or 90 gal/hour. Shower water is a mix of hot and cold water and depends on the supply water temperature, the desired shower water temperature, etc. For me, a mix of 50/50 seems a good mix. So 45 gph cold and 45 gph hot. Do the math and it does not look possible using only the same electric power supply that the 20 gal per hour tank heater has currently. So the power supply needs to be at least doubled for a whole house setup. My electric panel has 2 spaces for the 220/240 v circuit to the water heater. Sowtime says he needed 4 spaces, so it is nominally double. I know that there are various sizes of breakers and wires but you can check the specifics when you are considering a specific heater.

3. IMHO the quote re Rinnai on demand water heater providing hot water for 4 showers plus other users simultaneously has to be a gas fired heater not electric. I googled Rinnai and found no electric models at all.

4. The electric on demand water heaters such as ecosmart have electric power demands of 18 and 36 kw. 18 000 watts/240 volts = 75 amps required. 36 000 watts/ 240 volts =150 amps.

5. My electric power supply panel has a 200 amp breaker but needs to supply HVAC , stoves etc, when someone wants to take a shower. IMHO, the 18kw model can be possible but not the 36 kw. You still need to check the required wiring to make sure it will be adequate or need to be replaced.

6. NG or propane fired heaters are more suited to on demand systems than electric power units.
Good point. I'm not an electrical engineer either, but it looks like an electric tankless water heater needs about 4 times the breaker size as a tank type water heater (30 amps vs 120 amps). It may not be possible to add a 120 amp breaker to the existing electrical panel. The panel itself may need to be upgraded to accommodate a 120 amp breaker. Maybe someone else can clarify this.

[lawgolfer]

Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.
There should be no reason to replace a 10 year old water heater. Save your money and, instead, have the tank flushed and the sacrificial anode replaced and you'll get another 10 years service out of the present water heater.

Tankless water heaters are expensive. They also require yearly servicing to "descale" the tubes in which the water is heated. Although it is unlikely you will need it, should you lose your water service in a storm, you'll have 40 gal of water for emergency use if you have a regular water heater.

Many people believe that a tankless water heater will give them "instant" hot water. Not so, unless you have a tankless unit at each faucet. It will take just as long for hot water to reach the furthest faucet in your house if the tankless unit is installed at the same location as your present water heater. If you have to move the location of the tankless unit to outside your house, which you probably will, it may take even longer for hot water to reach your faucets.

If one of your goals is to have "instant" hot water, you should have the plumber who replaces the anode rod install a Watts recirculating pump at the hot water outlet of the water heater. These pumps cost $219 at Home Depot. They work in a unique manner. In addition to the pump, the kit includes a "manifold" which you install at the faucet furthest from the water heater (in some houses in TV, you will need two manifolds as the hot water line is split after entering the house, sending hot water in two directions). The manifold has internal valves that, when the hot water faucet is closed, directs the hot water into the cold water line and back to the tank. Hence when the hot water is not running, the pump is continuously pushing hot water at very low pressure throughout the house. Then, when a hot water faucet is opened, there will be hot water already at the faucet and you do not have to wait for it to travel all the way to the tank.

As the water being circulated travels from the tank, around the house, and back to the tank, it loses some of its heat. Thus, the hot water at the faucet closest to the tank will be very hot, the water at the last faucet in the circuit, not so hot. However, it only takes a few seconds for the hot water to arrive and it will be hot as the pipes in which it is flowing will already be warm.

The other downside, is that the cold water at a faucet will take some time before it is really cold. However, most everyone agrees that it is preferable to have hot water in a short time vs. always having cold water. (No one likes standing in the shower waiting for the hot water to arrive).

[lawgolfer]

I have to chime in with my two cents. I bought my pre-owned home here in late 2017. I already had a tankless heater. I have to let the water run for about 90 seconds before the hot water comes up. I've asked several professionals what I can do and they all told me there is a way to rig something up that would produce hot water faster, but it's expensive and probably not worth it. I live with the idea of wasting water everytime I need hot water.
There is no such thing as "instant" hot water unless you have a tankless unit at every faucet in the house (think of the small heaters some people have at the kitchen sink to fill a cup for tea or instant coffee). Wherever a whole-house tankless heater is installed, the water it heats still has to run through the pipes throughout the house to get to the faucets or showers.

If you have a whole-house tankless unit, you can rig a recirculating pump that will give you near-instant hot water throughout the house. You would connect the tankless unit to a holding tank-the best would be a small electric water heater of 10 gal. At the holding tank, you would install a Watts recirculating pump. The Watts pump would move hot water from the holding tank in a continuous loop throughout the house and, when a faucet is opened in the house, the tankless unit would kick on and replenish the water flowing from the holding tank to the faucet.

It will work, but it would be cheaper and easier to replace the tankless unit with a regular water heater and have the Watts pump added to the outlet of the water heater.

[retiredguy123]

Note that, if you want hot water to arrive faster to the shower, you can turn on the shower and a hot water faucet in the sink at the same time. That will reduce the wait by more than half the normal time. To reduce the time even further, replace the 1.5 gpm sink faucet aerator with a 2.2 gpm aerator, and replace the water saver shower head.

[jump4]

You will also increase the time to get hot water for your shower, etc.

Are you sure about this? I believe the time waiting for hot water to arrive at the shower would be based solely on distance to the hot water source. It should not matter whether that source is a tank of hot water or an instant tankless heater. If the tankless heater is installed in a location different than where the old water heater tank, then there could be a shorter or longer delay to get a hot shower.

[retiredguy123]

Are you sure about this? I believe the time waiting for hot water to arrive at the shower would be based solely on distance to the hot water source. It should not matter whether that source is a tank of hot water or an instant tankless heater. If the tankless heater is installed in a location different than where the old water heater tank, then there could be a shorter or longer delay to get a hot shower.
I think the point is that the water in the tank is already hot, but the tankless water heater needs to heat up the water.

[crazygery]

[/I]I agree, but it is almost impossible to determine the lifespan of an appliance. I have never had a tank type water heater fail, and the only one I ever replaced was more than 20 years old. I have also never done any maintenance, flushing or otherwise, on a water heater. To me, if your goal is to save money, the initial cost of an appliance is more important than speculating on how long you think something will last.

I have my tankless installed in my laundry room, my washer is very happy and since the bathroom is only 50 feet from the laundry room it works great, my wife has to wait a little longer because her bathroom is 250 feet away, but she’s very patient and doesn’t mind the 45 second wait. I’m just happy we have 2 bathrooms

[Normal]

Are you sure about this? I believe the time waiting for hot water to arrive at the shower would be based solely on distance to the hot water source. It should not matter whether that source is a tank of hot water or an instant tankless heater. If the tankless heater is installed in a location different than where the old water heater tank, then there could be a shorter or longer delay to get a hot shower.

Just the “Latency Effect” described another way. Instant isn’t absolute, about a gallon of water has to cycle out of the apparatus, the therm switch has to kick on, then the burner comes to temp and you get your hot water in the home system. This isn’t the Jetson’s or Star Trek, but it is continuous.

[sowtime444]

Over 25 years ago my wife and I build an oversized home and we had an instant water heater installed.
It did live up to its name we had instant hot water through the house, but we did run into one problem.
We had also installed a large tub that should had been listed as a small pool, by the time half of it was fill the water would turn cold.
Since I do not know the first thing about instant water heaters, I can't tell you if this is a problem with all instant hot water heaters or it was the way ours was installed.
But before you go forward with this find out if there is a capacity level.

I had a two person jacuzzi bathtub that I could fill with a gas powered tankless Bosch in 2001 without a problem. In Boston (ground water started at near freezing probably lol). This was the large capacity size tankless. Size does matter. ;)

[sowtime444]

[/I]

her bathroom is 250 feet away

I'd love to see that floor plan!

[sowtime444]

[/I]

I have my tankless installed in my laundry room, my washer is very happy and since the bathroom is only 50 feet from the laundry room it works great, my wife has to wait a little longer because her bathroom is 250 feet away, but she’s very patient and doesn’t mind the 45 second wait. I’m just happy we have 2 bathrooms

I have a whole home energy monitor. It isolated about 14 electricity consumers, including the water heater. I also have some smart home technology with a water heater switch.

To answer the question of savings of turning the heater off on a timer due to standby costs. I left a vacant home's tanked heater on for one week, then the next i ran it for 8 hours, 16 off. I repeated the two week cycle. No one was in the home, not a gallon of water was used.

My exact savings with a timer equated to 78 cents on a monthly basis.

No, a tankless heater will not save you money.

Your water heater was 100% electric and used no gas?

[jrref]

Electric tankless are not that good. Also, the existing electric supply to your electric tank hot water heater is not large enough to install a tankless so you will need an electrician to install a larger wire and breaker in your electrical panel. Not a big deal but that has to be done.

[Toymeister]

Your water heater was 100% electric and used no gas?

Yes, its appropriately named an electric water heater. Many homes here in The Villages have them.

[Steve]

If your goal is to save money, you won't do it by switching to a tankless system. Just my opinion.

I respectfully disagree. With a 40-50 gallon water heater you are periodically using gas or electricity to keep the water in the tank at a certain temperature--usually 140 degrees. Even if you're out of the house for the day or out of town for a week your water heater is doing that reheating process.

With a tankless water heater you only heat the water that is actually going through the system. If you're gone for a week no heating is done.

Having said that I have been told by those who have one that the electric tankless water heater does not work as well as the gas one. Ours is gas. We could turn the water on and leave it running for 24-hours straight and the water would still be coming out of the tap hot. I think ours is great and I think it's one of the best additions we have made to our home.

[Steve]

Just the “Latency Effect” described another way. Instant isn’t absolute, about a gallon of water has to cycle out of the apparatus, the therm switch has to kick on, then the burner comes to temp and you get your hot water in the home system. This isn’t the Jetson’s or Star Trek, but it is continuous.

Also the water in the pipe between the heater and the spigot is not heated. So that could water has to come out of the spigot before the hot water can come through. So whether you have a tank or tankless water heater the wait should be the same...if they were in the same location.

[Steve]

I had a two person jacuzzi bathtub that I could fill with a gas powered tankless Bosch in 2001 without a problem. In Boston (ground water started at near freezing probably lol). This was the large capacity size tankless. Size does matter. ;)

That's a good point. We installed a walk-in tub/jacuzzi in our guest bathroom and our old 40-gallon gas water heater couldn't provide enough hot water. With the tankless heater the water supply is unlimited and that solved the problem.

[biker1]

Out of curiosity, I looked at some specs. Essentially, you need to consider how many gallons per minute you will need and how much temperature rise will be required. The temperature rise is basically a function of location. For The Villages, if you want to be able to support 2 simultaneous showers you will probably need 3 40-amp breakers (120 amps) and the appropriate gauge wire run to the location of the tankless heater. An existing tank electric water heater is probably on a 30 amp circuit. It is possible that a typical 200 amp service will not support this with everything else in the house, in which case you would need to upgrade the breaker panel to support more amps.

I went through this previously when having a custom home built. Granted it was some time ago but I don't think things have changed all that much. My builder had put in several electric tankless water heaters and wound up replacing them with tank electric water heaters because the home owners were unhappy with the electric tankless. He had installed numerous gas tankless water heaters with good results. He was more than happy to put in a tankless electric but recommended against it. Where we were building, gas was not available and I wasn't going to install propane tanks. He did mention that it was lower cost to install the electric tankless during the construction of the house rather than try to retrofit the needed 100+ amps of wiring later on.

Electric tankless are not that good. Also, the existing electric supply to your electric tank hot water heater is not large enough to install a tankless so you will need an electrician to install a larger wire and breaker in your electrical panel. Not a big deal but that has to be done.

[Steve]

I think the point is that the water in the tank is already hot, but the tankless water heater needs to heat up the water.

But, regardless of whatever type of water heater you have, the water in the line between the water heater and the tap is not heated. So that cold water has to be flushed out before the hot water arrives. And the tankless heats the water instantaneously as the water goes through. There is no holding tank.

[Steve]

I had looked into this, but decided against due to several reasons:

1) In the long run, adding up all costs, it really doesn't save any appreciable amount of money.
2) The cost of the install is equal to or greater than the cost of the heater making this a losing $$ proposition. You can't do a self install if you want a warranty. Every manufacturer requires that installation be performed by a certified electrician for a valid warranty. If you install yourself, no warranty. I'm an Electrical Engineer, and this is a simple install.

Check with your electric or gas company. When we got ours the gas company paid for the installation. We just paid for the unit itself.

[Steve]

You will also increase the time to get hot water for your shower, etc.

On a side note, I have no idea what a tankless water heater costs, figure $200 or more for the connection, and if you are not handy the additional cost to flush (clean) the tankless water heater yearly. There was a company advertising on ToTV to replace a conventional water heater for under $900, and there was a 10% discount with the ad. I just did my own, water heater and some plumbing supplies was around $550, took 2 neighbors to help, and about 2 hours to complete the plumbing, so the $800 to $900 is not a bad price.

I have had out tankless gas water heater for several years now and I have never had to "flush" it. And there is nothing in the "Use and Care" Manual even suggesting it. Since no water is stored in it there is nothing to flush.

[Steve]

It is really nice to have a constant temperature, endless amount of hot water.

Since you are talking about electric, assuming you are installing the tankless in the same location as the tank. That would minimize the electrical costs. Also safe to ignore all the comments about how much longer it takes to get hot water with a tankless. There is no difference in output, just a difference in plumbing pipe distance.

There is a yearly flush that is beneficial to removing the scale that builds up. No anode rod to replace.

Size is measured by GPM and temperature rise.

An alternative I wish was done here is to have several smaller tankless heaters. One for master bath, one for 2nd bath, one for kitchen, and maybe one for laundry if not near one of the others. More cost, but near zero lag in getting hot water.

Operational costs should be less overall. You need the same amount of electrical energy to heat the water - maybe less because of efficiency. Need zero energy to keep a tank heated.

You will gain some space.

Check prices at big box stores, and at plumbing supply houses.

Replace the expansion tank too. Put a valve on it to make it easy to change in the future.

Many manufacturers offer a dedicated valve manifold. Get it. Makes installation so much easier, as well as performing maintenance.

While running power, try to have an outlet put in. Handy for a leak detection device. For either type replacement.

If you are hiring a plumber, check forums for recommendations. Also for people that have way overpaid for a F "happy" plumbing place.

Need zero energy to keep a tank heated? No tank's insulation is that good. Hang around your water heater for a while and see how often it turns on to reheat the water to the 140 degree setting even though no one is using any water at the time.

The tankless water heater only heats water as it passes through so it never uses any energy unless the water is running in the house somewhere.

And an expansion tank? Our unit is mounted on the outside of the house (which freed up some garage space) and there is no expansion tank or any kind of tank. It's a box mounted on the wall with the gas line and water line going in and an electric cord plugged in to an adjacent outlet. That's it!

[Steve]

I knew it. Spending a lot of money upfront to try to save money over 10 years is usually not a good plan. And, don't forget the time value of money, which further reduces any potential future savings.

Ever run out of hot water? You take a shower or bath. Then your wife wants to take a shower or bath and midway through filling the tub or taking that shower you run out of hot water? Doesn't happen with a tankless heater.

[OhioBuckeye]

Since my Rheem water heater is approaching 10 years in age I am considering having a tankless electric water heater installed instead. I am aware of the cost for electrical hook up as well as cost of the tank but am wondering what thoughts others have in regard to this consideration. I find it a waste of money to have water being maintained at temperature in existing 40 gal tank and thought a tankless system in the long run would be more efficient as well have a longer longevity. thoughts appreciated.. I’m sure it’ll be hooked up in garage & not outside like ours in northern Texas, how stupid was that, Tankless are cheaper to buy the great thing is they never run out of hot water, the bad thing is like ours you can only set it at 120 degrees at the most which for us is plenty hot enough. But me personally won’t buy another home with Tankless Water Heater outside, yea I know this was very stupid, me myself feel like a slave to my Tsnkless Water Heater. We have a new home & I’m a slave to it in winter. So to answer your question put your Tankless inside somewhere. Also they are cheaper to run!

[Maker]

Need zero energy to keep a tank heated? No tank's insulation is that good. Hang around your water heater for a while and see how often it turns on to reheat the water to the 140 degree setting even though no one is using any water at the time.

Sorry. Perhaps the wording I picked was not clear enough.
A tankless unit has no tank, so it cannot use energy to keep a tank of water heated.
No tank = no energy use for doing reheats.

[OhioBuckeye]

Wait a min. what does tankless have to do about it, but that’s what they call them, “Tankless Water Heaters. What’s your point?

[Jhnidy]

I have a whole home energy monitor. It isolated about 14 electricity consumers, including the water heater. I also have some smart home technology with a water heater switch.

To answer the question of savings of turning the heater off on a timer due to standby costs. I left a vacant home's tanked heater on for one week, then the next i ran it for 8 hours, 16 off. I repeated the two week cycle. No one was in the home, not a gallon of water was used.

My exact savings with a timer equated to 78 cents on a monthly basis.

No, a tankless heater will not save you money.

If no water was used, how much would the tankless system cost to run for the rest of your life? That number is missing in your test.

[Normal]

I have had out tankless gas water heater for several years now and I have never had to "flush" it. And there is nothing in the "Use and Care" Manual even suggesting it. Since no water is stored in it there is nothing to flush.
I thought the same but gave it a whirl with a DIY kit from Lowe’s for about a hundred bucks. When I ran it there was evidence of scaling etc. After doing it, I have made up my own mind to do it about every 2 years. It only takes about 20 minutes.

[Toymeister]

If no water was used, how much would the tankless system cost to run for the rest of your life? That number is missing in your test.
In the real world people use hot water in an occupied home leaving whatever sort of water heater their home has on. In a unoccupied home most people shut off a tank heater but they leave a tankless heater on.

A unoccupied home with a tankless heater on costs 72.4 cents in electricity per month (the sensor that checks for water flow is always on), while the same one with a tanked heater, shut off at the breaker, is zero.

My test was designed to test how much standby costs a tanked heater cost and if a water heater timer is economical. It did that.

You appear to want to know the efficency of heating water in a tanked heater or a tankless. It is the same. The overall efficency of heating water by electricity exceeds 99%, whereas the efficency of a tanked water heater is 97% the 2.xx% difference is standby costs or put a other way the cost to keep 40 gallons of water waiting for your use.

[huge-pigeons]

Most people don’t understand what an instant hot water heater is and what the benefits are, and a lot of people don’t understand the older hot water tanks. Unless you have a recirculating system for your hot water, it will take the same amount of time for hot water to get to each faucet/shower head. A 40/60 gallon tank of hot water will not get the hot water any sooner than an instant hot water heater.
Using the old fashion hot water tank, if you heat your water to 120 degrees and never use your faucets/showers while on vacation, you are paying for that water to be heated.
If you don’t have natural gas, don’t even think about a whole house tankless water heater, the electrical heaters are not that good compared to the natural gas units.
IMO, if you don’t have natural gas, then go all out and buy a newer tank hot water heater and put in a recirculating system in at the same time. If you have gas, then go tankless and put in a recirculating system in at the same time.

[sowtime444]

You will also increase the time to get hot water for your shower, etc.

On a side note, I have no idea what a tankless water heater costs, figure $200 or more for the connection, and if you are not handy the additional cost to flush (clean) the tankless water heater yearly. There was a company advertising on ToTV to replace a conventional water heater for under $900, and there was a 10% discount with the ad. I just did my own, water heater and some plumbing supplies was around $550, took 2 neighbors to help, and about 2 hours to complete the plumbing, so the $800 to $900 is not a bad price.

I had a Bosch tankless installed in 2001. Sold that house in 2017 with the tankless still working. Never had a single service call on it. Never did a yearly flush. Never even heard of a yearly flush!

Had a Rinnai tankless installed in 2010, different house. Never have done a flush. Never had a service call on it. Still renting that house out.

Those are/were both gas models.

Third house, full electric tankless installed in 2017. Never have done a flush.

[Maker]

Home Depot has water heaters on sale on Dec 15 as the deals of the day. Sale ends at midnight.

[rjm1cc]

That's a good point. We installed a walk-in tub/jacuzzi in our guest bathroom and our old 40-gallon gas water heater couldn't provide enough hot water. With the tankless heater the water supply is unlimited and that solved the problem.

Agree that the 40 gallon heater can not meet the needs of a walk in tub UNLESS you turn it up to maximum about 1/2 hr before you need the water. This is what I do. I probably keep that tank at about 120 degrees. A little below the 1/2 mark on the controller.

[retiredguy123]

I respectfully disagree. With a 40-50 gallon water heater you are periodically using gas or electricity to keep the water in the tank at a certain temperature--usually 140 degrees. Even if you're out of the house for the day or out of town for a week your water heater is doing that reheating process.

With a tankless water heater you only heat the water that is actually going through the system. If you're gone for a week no heating is done.

Having said that I have been told by those who have one that the electric tankless water heater does not work as well as the gas one. Ours is gas. We could turn the water on and leave it running for 24-hours straight and the water would still be coming out of the tap hot. I think ours is great and I think it's one of the best additions we have made to our home.
See Post No. 5. The OP was asking if he could save money in the long run by incurring the extra cost of switching from a tank type water heater to an electric tankless water heater. The answer to the OP's question is clearly no.

[retiredguy123]

That's a good point. We installed a walk-in tub/jacuzzi in our guest bathroom and our old 40-gallon gas water heater couldn't provide enough hot water. With the tankless heater the water supply is unlimited and that solved the problem.
A 40 gallon water heater is never large enough to accommodate a Jacuzzi type tub. Typically, when a builder includes a Jacuzzi tub in a new house, they install at least a 60 gallon water heater. That is a standard construction design.

[Maker]

See Post No. 5. The OP was asking if he could save money in the long run by incurring the extra cost of switching from a tank type water heater to an electric tankless water heater. The answer to the OP's question is clearly no.

Correct answer is not always "no". It depends upon several factors.

Perhaps someone wants a bigger size tank because their usage cannot be met adequately with a smaller tank before the "hot" water becomes "cold".
Such as: Jacuzzi type tub cannot be filled with hot enough water? People need to take showers in succession or parallel? Running out of hot water for several things operating at the same time? Tired of the water cooling off during a shower.

So they decide to get a bigger tank to alleviate some of those issues. If they pick a tank >50 gallons, then federal regulations kick in that mandate a more efficient tank with increased insulation and using a heat pump system. The cost for that tank is much higher than a tankless heater (double or more). It is also a lot bigger and might not fit in an existing location.

So in that case, the answer is clearly "yes"; a tankless is the better choice since initial cost would be significantly lower.

[retiredguy123]

Correct answer is not always "no". It depends upon several factors.

Perhaps someone wants a bigger size tank because their usage cannot be met adequately with a smaller tank before the "hot" water becomes "cold".
Such as: Jacuzzi type tub cannot be filled with hot enough water? People need to take showers in succession or parallel? Running out of hot water for several things operating at the same time? Tired of the water cooling off during a shower.

So they decide to get a bigger tank to alleviate some of those issues. If they pick a tank >50 gallons, then federal regulations kick in that mandate a more efficient tank with increased insulation and using a heat pump system. The cost for that tank is much higher than a tankless heater (double or more). It is also a lot bigger and might not fit in an existing location.

So in that case, the answer is clearly "yes"; a tankless is the better choice since initial cost would be significantly lower.
I was just responding to the OP's simple question which was "will I save money by replacing my 40 gallon tank type water heater with a tankless water heater?" He didn't mention anything about a Jacuzzi tub. The answer to the OP 's question is "no" because he will never recover the upfront cost to retrofit a tankless water heater into the house. Obviously, if you want to apply additional factors that were not mentioned, you could get a different answer.

[coffeebean]

Ever run out of hot water? You take a shower or bath. Then your wife wants to take a shower or bath and midway through filling the tub or taking that shower you run out of hot water? Doesn't happen with a tankless heater.

We have a conventional 40 gallon gas hot water heater. We have never run out of hot water. Two consecutive showers (mine at least 20 minutes; hubby 5 minutes) and run the washing machine at the same time and still have plenty of hot water. We don't use the tub for baths so that may be a problem if we did.

[biker1]

Not correct. There are some proposed standards that could take place in the future but you can buy an electric hot water heater today that is greater than 50 gallons and doesn't use a heat pump.

Correct answer is not always "no". It depends upon several factors.

Perhaps someone wants a bigger size tank because their usage cannot be met adequately with a smaller tank before the "hot" water becomes "cold".
Such as: Jacuzzi type tub cannot be filled with hot enough water? People need to take showers in succession or parallel? Running out of hot water for several things operating at the same time? Tired of the water cooling off during a shower.

So they decide to get a bigger tank to alleviate some of those issues. If they pick a tank >50 gallons, then federal regulations kick in that mandate a more efficient tank with increased insulation and using a heat pump system. The cost for that tank is much higher than a tankless heater (double or more). It is also a lot bigger and might not fit in an existing location.

So in that case, the answer is clearly "yes"; a tankless is the better choice since initial cost would be significantly lower.