All of the points mentioned in this thread are well taken. There are benefits to having a system with a dedicated return line and also to having an installation that uses the crossover pipe methodology. Also, depending on the size of your home and the location of your primary bathroom to the water heater, an argument could also be made for doing nothing.

When I built my home about a year ago, we were offered the option to have a system installed with a dedicated return line for a cost of about $8000. This was not a value proposition for me. Clearly, the system using the dedicated return line also uses a different, more expensive water heater. The cost between one that allows for water circulation and one that doesn’t only differs by about $600 in most cases and for that reason does not justify, in my opinion, the $8000 cost.

I opted to install my own system and purchased two crossover pipes that I installed in the master bathroom and in the second secondary bathroom of the home. I plumbed in a recirculating pump which cost me roughly $90. I also added an Alexa plug that allowed me to create a routine in Alexa to turn on the recirculation pump anytime I needed it. The routine is set to run for two minutes and 45 seconds, the approximate time it takes to get hot water to my bathroom. The pump automatically turns off after that time.

While this solution does not provide me with on-demand hot water or instant hot water, it does preclude my having to waste 6 to 7 gallons of water every time I want to take a shower while waiting for the water to heat up.

Obviously this is not the best solution but definitely a fair trade-off for not paying $8000.

Pretty close, but I had to do my own calculation.

The actual inside diameter of 3/4-inch Schedule 40 plastic pipe is 0.804 inches.
The radius is 0.804/2 = 0.402 inches.
The area is 0.402 x 0.402 x 3.14 = 0.507 square inches.
The volume for 50 feet of pipe is 50 x 12 x 0.507 = 304.2 cubic inches
The volume in cubic feet is 304.2 x 0.0005787 = 0.176 cubic feet
The volume in gallons is 0.176 x 7.48 = 1.32 gallons

The Federal regulation for shower heads is 2.5 GPM maximum, so it should take about 32 seconds to get hot water to the shower. But you can reduce that time by about half by turning on a sink faucet at the same time as the shower.

I installed a mini electric hot water heater under sink. Plugs into disposal outlet and run hot water supply through the heater
Instant hot water and if you let it run the the water stays hot as the circuit heater warms supply water.

Yeah, I didn't look up the actual inside diameter of a schedule 40 plastic tube. If the plastic tubing in the hot water run meets the average I.D. of 0.804" then it turns out my "about 1 gallon" figure missed your actual figure by 22oz (just under three cups).

I didn’t say it would run constantly, I said it would run more.

Simple solution…TacoGenie
 

Here’s a fairly simple solution for well less than $1K.

I’ve installed these on a couple of houses we’ve owned. No water loss/dumping. When ready to take a shower, just hit the button (I’ve hidden right inside the cabinet). The quiet pump turns on, and the crossover keeps from wasting water…then when water is up to the set temp, it shuts off. If typically takes 20-40 seconds. That brings the hot water to that pump. I’ve installed it right below the sink in the master bath, which is the furthest from the garage HWH. Then when you turn on the shower, it’s hot & ready to go.

The problem with timer units, on top of the HWH, is that you don’t always take showers the same time, when the timer is activated. With this unit you just hit the button.

- If your goal is instant hot water then a recirculating system is the answer

- If your goal is to save water (maybe 1,000 gals/yr) then a recirculating system is the answer

- If your goal is to save money by not wasting water then figure about $0.01/gal and 1,000 gals/yr or about $10/yr. (the $600 system would take about 60 years to pay off)

- If your goal is to save electricity then a recirculating system will do just the opposite, it will cost you electricity both in the pump and in reheating the water

Whatever your goal is, $8,000+ seems like an expensive way to achieve it.

I have a tankless system and I got tired of waiting ~85 seconds for hot water to get to the shower head. I installed a circulating pump with crossover at the farthest sink. Plugged it into an Alexa enabled outlet and programmed it to run for 5 minutes and then shut off. Prior to taking a shower, we simply say, “Alexa pre-heat water” and head the bathroom. Pump turns on, fires the burner, heats water, circulates for 5 minutes and shuts off while I am in the shower. Hot water arrives at the shower head in 25 seconds. Would be quicker if the main run were closer to the shower.

We have a Watts re-circualting pump connected to our gas water heater. The Watts pump itself does not have a temperature setting that I know of. I do not see it. The pump re-circulates the hot water at the temperature the hot water heater is set at. We have a Watts "gizmo" under the sink in the kitchen which is midway from the hot water heater and in the hall bathroom sink which is at the furthest end of the house. Those are the only two locations that take time getting hot water.

No. We had a new "gizmo" put on the furthest point under the bathroom sink and that fixed that problem, pronto. I never realized that the "gizmo" we had before was defective. Now, when I turn the cold water on, it takes five seconds to get cold water. Yippeeee.

In our home, it would take a minute and a half to get even warm water to the sink in the hall bathroom which is furthest from the hot water heater. I refuse to wait that long. I'm spoiled I guess. LOVE, LOVE, LOVE my Watts re-circ pump. My timer is set to turn the pump on at 6am and goes off at 10pm.

I don't have a whirlpool tub to fill in my house so I've never run out of hot water with our 40 gal. hot water heater. It has stood the test by providing enough hot water for four showers when we have guests. The water heats so fast too after the hot water heater was turned OFF for more than a week when we were out of town. No lie.......20 minutes after turning on the pilot and firing up the heater we had hot water as hot as the temperature is set. No complaints from me.

Telephone, email to the seller, builder, agent might be better than Talk of the Villages.

This is the correct solution. I have the same arrangement only using Google. Timer systems don't work because your schedule probably varies. Push button systems are OK but Google and Alexa and an inexpensive smart plug works the best. All these "other" systems may work to some extent but they all have their shortcomings. The facts are waiting for hot water to reach your shower, for example, wastes water. Over time whatever the cost, it adds up. For a reasonably small investment you can install the pump and crossover device either by doing it yourself or hire a plumber and add the Google or Alexa smart plug yourself.

The only thing you need to be aware of is with the tankless systems installed in the newer homes, you need a special circulator pump that moves enough water to trigger the system. You will need to search Talk of the Villages to find the thread where this was discussed and I would probably hire a professional like Mike Scott, Dove or your favorite plumber to install the pump on these devices.