Installing a hot water booster heater versus hot water recirculating setup

[HawkinsHollow]

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.

Are you an tankless or tanked? That is my first step, I need to insulate the hot before I even think about doing anything else.

 

[IXLR8]

Be careful on recirculate pump sizes. I have about 70ft from my tankless water heater to my shower, 140ft round trip. I bought a name brand pump ($380) that was listed as a recirculator pump. I could not find the pump curves before I bought it. Installed it, didn't work. Finally found the pump curves, and they showed that pump was not up to pumping water thru that much piping. Couldn't return it as I had installed it. I ended up buying a Taco 007 pump ($760) that had the pump curves to match the load of that much piping.

 

[grsthegreat]

Are you an tankless or tanked? That is my first step, I need to insulate the hot before I even think about doing anything else.

Twin 40 gallon gas direct vent units. The return is piped into the intake side with a back flow installed

 

[grsthegreat]

Be careful on recirculate pump sizes. I have about 70ft from my tankless water heater to my shower, 140ft round trip. I bought a name brand pump ($380) that was listed as a recirculator pump. I could not find the pump curves before I bought it. Installed it, didn't work. Finally found the pump curves, and they showed that pump was not up to pumping water thru that much piping. Couldn't return it as I had installed it. I ended up buying a Taco 007 pump ($760) that had the pump curves to match the load of that much piping.

Good point. I have aprox 100’ round trip on mine. My Grundfos pump handles that without issue.

Hard to see in pic, but its to the top of the left waterheater mounted on block. The blanket was temp while soldering final connections.

 

[ericm979]

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.

With three faucets I would go straight to the recirculating pump solution. That will get you hot water to all the faucets at about the same cost. A tank or on demand heater will still have a run from the heater to the faucets, even if it's closer than the main tank. So there will still be a wait.

Assuming the heaters are roughly the same efficiency and are all electric the cost for electricity should be about the same. You use X amount of hot water. It can come from heater 1 or heater 2.

However I think that a small tank heater probably loses heat faster than a large one just due to the surface area/volume relationship. More insulation would rectify that but I doubt they do that.

 

[ultrarunner]

Here is a sink in the annex some distance away that is plumbed with only cold water and no recirculating loop…

It’s been 10 years since installation with out issue.

 

[IXLR8]

Good point. I have aprox 100’ round trip on mine. My Grundfos pump handles that without issue.

Hard to see in pic, but its to the top of the left waterheater mounted on block. The blanket was temp while soldering final connections.View attachment 3083991

Grundfos makes a good pump, bet it was closer to $800 than $300

 

[grsthegreat]

Grundfos makes a good pump, bet it was closer to $800 than $300

No, it was about $350. when i replaced it last year.

 

[ponytug]

I got mine on sale for $150 as a kit of the pump, plus replaceable "H" valve at the faucet, and all of the flex pipe. The pump alone was $300, but the kit was far cheaper. "Marketing" I guess.

All the best,

Peter

 

[kebo]

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

The reason I was thinking of going with a 120V unit is to avoid having to run a new 220V circuit from the breaker panel to the other end of the house. If I go with 120V, I think I can use an existing 120V circuit already under the house that is only being used to power a GFCI outlet on the front side of the house for Christmas lights and the occasional electric hedge trimmer to trim bushes. I am not comfortable tying in a new 220V circuit to my breaker box, so that would up the cost a good bit to have a pro do it. Thanks.

 

[kebo]

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!

Yes, the new tank would be installed under the house and piped in just in "front" of the first bathroom that the long run from the water heater gets too. They are in "series", from what I can tell of the plumbing, so it would then provide hot water to BOTH baths. Thanks!

 

[AnotherBueller]

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!!!

I don't understand the difference between #1 & 2, but ether way #I think would be best.
Any recirculating system, even with pipe insulation, will result in heat loss because the water is circulating all the time, so the water heater will have to work more = more money. Just measure how much water come out of the faucet and multiply it by 1 1/2 or 2. That's a good size heater to get. (since cold water is refilling the booster as you are pulling hot out). I forget the math.

 

[AnotherBueller]

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

Need a 2 pole circuit breaker and dedicated 3 wire circuit for 220V

 

[AnotherBueller]

The reason I was thinking of going with a 120V unit is to avoid having to run a new 220V circuit from the breaker panel to the other end of the house. If I go with 120V, I think I can use an existing 120V circuit already under the house that is only being used to power a GFCI outlet on the front side of the house for Christmas lights and the occasional electric hedge trimmer to trim bushes. I am not comfortable tying in a new 220V circuit to my breaker box, so that would up the cost a good bit to have a pro do it. Thanks.

There is a way to turn that circuit into a 220 and 110 but it will NOT met code and hasn't for a long time.

 

[kebo]

Be careful on recirculate pump sizes. I have about 70ft from my tankless water heater to my shower, 140ft round trip. I bought a name brand pump ($380) that was listed as a recirculator pump. I could not find the pump curves before I bought it. Installed it, didn't work. Finally found the pump curves, and they showed that pump was not up to pumping water thru that much piping. Couldn't return it as I had installed it. I ended up buying a Taco 007 pump ($760) that had the pump curves to match the load of that much piping.

Thank you for that info! If I go with option #1 or # 2, I will definitely keep this in mind.

 

[BackRoad]

We built with option 3, using a 120v, 6 gal water heater in a small space in the Master Closet, feeding the Master Bath and Laundry room. It works great and is efficient as it never heats cold water since it's being fed with already hot water from the boiler.

Except...I'm seriously thinking about changing it to 8 gals.

For the shower in the winter, it's instant hot water for about 6 minutes, but since it's near 100 feet from the on-demand gas hot water boiler in the garage, minutes 6 and 7 are luke warm, then it's back to forever hot from minute 8 on...

I think an 8 gal would allow sufficient volume for mixing the cold water in the 100' run plus bridge the minute or so for the garage on-demand to generate hot water.

It's less noticeable in the other 3 seasons when warm rather than hot water is generally used.

The footprint is minimal, and the 8 gal wouldn't be much bigger, and shouldn't cost much more on average to operate.

The boot was included for size reference in the 1st photo! And the reflected green light is visible from the cubby hole behind the door in the 2nd photo.

 

[grsthegreat]

We built with option 3, using a 120v, 6 gal water heater in a small space in the Master Closet, feeding the Master Bath and Laundry room. It works great and is efficient as it never heats cold water since it's being fed with already hot water from the boiler.

Except...I'm seriously thinking about changing it to 8 gals.

For the shower in the winter, it's instant hot water for about 6 minutes, but since it's near 100 feet from the on-demand gas hot water boiler in the garage, minutes 6 and 7 are luke warm, then it's back to forever hot from minute 8 on...

I think an 8 gal would allow sufficient volume for mixing the cold water in the 100' run plus bridge the minute or so for the garage on-demand to generate hot water.

It's less noticeable in the other 3 seasons when warm rather than hot water is generally used.

The footprint is minimal, and the 8 gal wouldn't be much bigger, and shouldn't cost much more on average to operate.

The boot was included for size reference in the 1st photo! And the reflected green light is visible from the cubby hole behind the door in the 2nd photo.View attachment 3113365View attachment 3113366

Id install a water leak detector/alarm in that pan

 

[BackRoad]

Mr. Grsthegreat, appreciate the kick in the @rse!

We had them in the basement at our old house, but I've not ordered them for this house...

Counted up the potentials with 8 now in the cart on Amazon...Thank You!

 

[ponytug]

Mr. Grsthegreat, appreciate the kick in the @rse!

We had them in the basement at our old house, but I've not ordered them for this house...

Counted up the potentials with 8 now in the cart on Amazon...Thank You!

Do you have a favorite brand/type? (@grsthegreat, too?)

All the best, Peter

 

[grsthegreat]

Mr. Grsthegreat, appreciate the kick in the @rse!

We had them in the basement at our old house, but I've not ordered them for this house...

Counted up the potentials with 8 now in the cart on Amazon...Thank You!

I learned by fixing the damage caused by an unseen leak. I have 8 in use now. One went off about 2 weeks ago, found clog in condensate drain pan of furnace. Could have been a mess.