[Steve]

Originally Posted 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.

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]

Originally Posted by 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.

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]

Originally Posted by 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.

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]

Originally Posted by retiredguy123

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]

Originally Posted by 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.

. 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]

Originally Posted by Steve

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]

Originally Posted by 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.

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]

Originally Posted by Steve

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]

Originally Posted by Jhnidy

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]

Originally Posted by 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.

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]

Originally Posted by Steve

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]

Originally Posted by Steve

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.