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.