Installing a hot water booster heater versus hot water recirculating setup

   / Installing a hot water booster heater versus hot water recirculating setup #1  

kebo

Elite Member
Joined
May 16, 2006
Messages
2,928
Location
Lexington, SC
Tractor
2001 John Deere 790 4x4, bar tires
Hi all, wanted to get some opinions and feedback on an issue with the layout of our ranch style house. It has two baths, which are on one end of the house, and a two car garage, which is on the other end the house. I haven't measured, but I would guess it's about 70 ft run or so from the water heater to the closest bathroom. The problem is the electric water heater is currently located in the garage, so as you would expect, on a cold winter morning it takes a WHILE before you get any hot water coming out of the faucets in the two baths. This of course is very wasteful! Yes, I have already wrapped all of the hot water lines under the house, but that only does just so much. (House is on brick foundation with about 3ft of crawlspace btw). So, my options are:
1) Install a hot water recirculating setup with a bypass valve under the bathroom sink that is farthest from the water heater, and also install a recirculating pump on the water heater to circulate the water.
2) Install a new hot water dedicated return line at the end of the line (farthest bathroom) along with a recirculating pump on the water heater.
3) Install a smaller booster water heater in the hot water line that is just in front of the "first" bathroom. That would mean it would be on the end of the house where the two bathrooms are located at. That will provide a much shorter "run" for hot water to get to the bathrooms.

Right now, I am leaning towards option #3, as I can install it and use three shutoff valves to either allow water to go through the booster water heater, or bypass it altogether. That way, if I am not happy with how it works out I could just take it out of the hot water line altogether and disconnect the wiring. I think a smallish booster heater, like maybe 18 gallons are so that runs on 115V would suffice?? That way, I wouldn't have to run a new 220V circuit to that end of the house, because my breaker panel is also close to the garage.

Also, I should mention that the kitchen and washer are right next to the garage, so if you suggest moving the hot water heater entirely to the other end of the house that would simply change the problem to having to wait for hot water at the kitchen sink!!!! It currently takes just about 90 seconds to get hot water in the farthest bathroom sink. If I install a small booster water heater, it only needs to provide hot water for a short time, because it doesn't have to heat water once the heated water from the 50 gallon water heater in the garage starts flowing through it. Am I thinking this right, or did I miss something?? Thanks!!!
 
   / Installing a hot water booster heater versus hot water recirculating setup #2  
We have your #2 option and after being spoiled now with it for 10 years, ain't no goin' back. It is on a timer so it kicks on before the wife gets up and off after bedtime.
Don't even know it is there until "spring forward" time change and "The water is cold this morning!" discussion starts.
In the old days, we'd get up, turn the shower on, go to the kitchen and start the coffee, return to the bathroom as it finally started to get hot. Now its instantaneous. And the coffee maker is now on a timer too.;)
 
   / Installing a hot water booster heater versus hot water recirculating setup #3  
I have the timer option on my recirculating pump…

Adding the timer I noticed a drop in the gas bill… gas water heater here.

The low flow shower heads and faucets means it takes a long time for HOT water to reach the kitchen without the pump.

I also have an Insta-Hot in the kitchen the previous owners used a lot but I unplugged it because it did not pencil out for how little I used it.

One of my friends thinking bigger is better did his entire home in 3/4 and 1 inch copper and it takes forever with low flow for hot water…

I’m a big believer in smaller lines to sinks…
 
   / Installing a hot water booster heater versus hot water recirculating setup #4  
I put a little 2.5 gallon water heater under the kitchen sink as a booster and it has worked out well. Instant hot water and since tied to main heater never run out of hot water.
 
   / Installing a hot water booster heater versus hot water recirculating setup #5  
We have your #2 option and after being spoiled now with it for 10 years, ain't no goin' back. It is on a timer so it kicks on before the wife gets up and off after bedtime.
Don't even know it is there until "spring forward" time change and "The water is cold this morning!" discussion starts.
In the old days, we'd get up, turn the shower on, go to the kitchen and start the coffee, return to the bathroom as it finally started to get hot. Now its instantaneous. And the coffee maker is now on a timer too.;)
I added a pipe from furthest bath to WH and a timed recirc pump also about 10-12 years ago. I had to replace the pump motor last year, but other than that, it works flawlessly. About 1 second to get hot water in any house faucet.
 
   / Installing a hot water booster heater versus hot water recirculating setup #6  
@kebo Grundfos and Watts make systems with a thermostatic valve at the most distant faucet and a small pump on a timer.

If you have the option of downsizing the pipe by switching to PEX for the long run to the far faucets, the lower volume of water in the pipe will help. Generally, a smaller diameter PEX pipe can sustain the same flow as larger copper pipes due to reduced friction.

All the best,

Peter
 
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   / Installing a hot water booster heater versus hot water recirculating setup #7  
I put a little 2.5 gallon water heater under the kitchen sink as a booster and it has worked out well. Instant hot water and since tied to main heater never run out of hot water.
That sounds exactly what I am looking for. What did you use for a water heater? Thanks
 
   / Installing a hot water booster heater versus hot water recirculating setup #8  
That sounds exactly what I am looking for. What did you use for a water heater? Thanks
I also added a small 110volt water heater in line .By the time the hot water has run out, the hot water from my tankless has arrived. Pipe hot water into 2.5 gallon from my tankless, and hot out to my bathroom
works great !
 
   / Installing a hot water booster heater versus hot water recirculating setup #9  
What do figure the kW it uses over the year?

The circulating pump is very efficient but water heater is on more keeping the lines hot all
The time.
 
   / Installing a hot water booster heater versus hot water recirculating setup #10  
Timely post!! I am in a similar situation after installing a tankless this summer. To truly solve the issue using the small tankless you would need one at every faucet right, including the shower? It seems like the recirc pump would be the best option unless you want to install 3 small tank heaters.
 

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