Installing a hot water booster heater versus hot water recirculating setup

[kebo]

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.

I was thinking of adding just one small water heater, not three! Obviously I want to solve the problem the cheapest way I can. If I set it up with three valves I can bypass the remote water heater tank (near the two baths) if I wanted to. That way, I could come back and install the recirculating setup if I wanted too and see how well it does. I'm just trying to decide which is the best/cheapest way to start with!

 

[kebo]

@kebo Grundfos and Watts make systems with a thermostatic valve at the most distant faucet and a small pump on a timer.

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www.amazon.com

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

Yep, I was aware of recirc pumps that have timers on them, and the bypass valves with thermostats built in. I wasn't planning to replumb the long run (which is 1/2" copper) with PEX, that would increase the cost to solve my issue. Thanks for the input though.

 

[kebo]

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.

Good question! I haven't tried to calculate the costs of a water heater by itself and then compare it to the cost of a recirc pump. The problem is I don't know how much my water heater is on or off during a monthly billing cycle. Nor do I have any idea how much the recirc pump would run (if I installed one). As I've mentioned, when/if I install a remote water heater tank, I'm going to plumb it in with three valves so I can essentially bypass it if was costing too much, and then perhaps try the recirc pump method.

 

[ultrarunner]

Back before the low flow mandates it didn’t take so long for hot water to reach distant faucets…

I put a new bathroom faucet in for grandma and she was not happy and kept a pail to catch the cold water because California was in a drought.

I ended up pulling the low flow disc from the aerator which helped to lesson the time but now she was aware of the wasted water.

 

[oldnslo]

That sounds exactly what I am looking for. What did you use for a water heater? Thanks

I just purchased the 2.5 gallon round 120 VAC water heater from a local box store. No clue if added to electric bill but suspect minimal since I have a well so running extra water down the drain waiting for it to get hot was costing me money also.

Since in cabinet under the sink any escaping heat helps warm the house in winter.

 

[sandman2234]

I have the same issue with the house across the street, and just replaced the water heater. However, that house is on a slab, so no crawl space. I am considering a small hot water heater inline, but tearing out all that sheetrock to get to the lines, and where to put the new heater is an issue.
Keto (original poster) mentioned he would rather go 120v versus 220v, which I don't follow. Wire size for a 220v circuit is less than a 120v circuit when drawing the same amps.
David from jax

 

[HawkinsHollow]

I was thinking of adding just one small water heater, not three! Obviously I want to solve the problem the cheapest way I can. If I set it up with three valves I can bypass the remote water heater tank (near the two baths) if I wanted to. That way, I could come back and install the recirculating setup if I wanted too and see how well it does. I'm just trying to decide which is the best/cheapest way to start with!

So you are planning on adding the tank inline BEFORE it splits to the showers and sinks in the 2 different bathrooms? That is the only way the tank is going to to solve your issue. If you install it in the sink vanity it will only solve the issue to that sink. That is my predicament. Since installing the tankless it takes 45 seconds-1.5 minutes to get to ANY of the faucets in the house. Even the ones directly above the hot water heater. So really I feel like the only thing to do in that case is a recirc pump. We moved back into our house end of November and I have not washed my hands with hot water since, because I don't want to wait for a minute to wash my hands, really annoying!

 

[ultrarunner]

I remember my great great aunt lived in a very old home and above the kitchen sink she had a small maybe 2 gallon water heater.

She prepared meals and before sitting at the table turned on her over sink water heater which ensured hot water for dish washing…

On demand point of use hot water in its simplest form.

At work the lavatory sink in the annex has a small electric on demand water heater… it was value engineered as cost effective as opposed to extending the recirculating loop for a sink maybe used 10 times per day Monday through Friday

 

[Quaffer]

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 !

This is effective and maybe the lowest in cost.

 

[grsthegreat]

Honestly, my return line was 1/2” copper, insulated entire way back to garage, maybe 50 feet. If you feel the return line right before the 1/25th HP circ pump, its almost same temp as pipe out of water heater. Thees not much heat loss thru system, so water heater doesnt run continually. I bet the water heater runs less time with pump as before, as im not having to let 10 gal of water run before i got hot water. Than this water just sits in pipes cooling off until next time.