Best water heater for house addition

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28fe6
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Joined: Wed Jan 03, 2018 9:01 am

Best water heater for house addition

Post by 28fe6 »

I'm planning a 500sqft addition to my 1800 sqft house, with a shower and garden tub.

The current 40gal water heater is barely enough for the house as it is. And the addition is very far away from the existing heater as possible.

There's two things I hate: running out of hot water, and having to wait a long time for hot water. With the new water saving fixtures it seems to take forever for water to turn hot.

I could upgrade my current tank to a 80gal bigger one. But I would still have to wait a long time for hot water in the addition.

I could put a "booster" tank in the addition. One of the lowboy jobs. But I'm not sure if I should plumb that in series with the primary, or just dedicate it to the fixtures in the addition. I'll have a big tub, so a small tank might not be enough if it's plumbed dedicated.

I could put a tankless in the addition. I'd have to run gas, they are hella expensive, I never liked how long it takes for the water to start coming out hot, and it doesn't do anything about my marginal main tank.

I could just upgrade my main tank to a big tankless for the whole house with addition. Doesn't solve my problem of having to wait a long time for hot water, but it would fix the capacity problem.

I could install a tankless as my main water heater, then put a little electric booster in series in the addition, so I get instant hot water AND infinite capacity. Os that possible?

What would you do?
livesoft
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Re: Best water heater for house addition

Post by livesoft »

Our natural gas 30 gal heaters are directly above two different bathrooms in our home. One of those bathrooms is the Master bath. We have never run out of relatively instant hot water. And when we have had to replace a heater, the other one was still giving hot water.
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hudson
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Re: Best water heater for house addition

Post by hudson »

28fe6,

I would consult with a good local plumber.
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Sandtrap
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Re: Best water heater for house addition

Post by Sandtrap »

90 gallon with a hot water circulating pump on a timer?

Best advice would be from calling several reputable licensed plumbers and have them look at your exact setup and what your needs are.

Call a plumbing contractor pro for on-site advice and suggestions.
j :D

What we have but doesn't apply to anyone else because every home and need is different.
90 gallon gas water heater with hot water recirculating pump on a timer.
5000+ s.f. 3 story, 4 bath, etc.

to op:
you would gain a whole lot by upgrading the existing small water heater to a 90, etc, gal and a recirculating system of various types added in. The addition is only 500 sf and you'd have to weight the cost benefits hassle factor, etc, of running a new Hot Water elec circuit to the new location, etc, etc.
Thus. .talk to a pro w onsite inspection and toss around some ideas.
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mgensler
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Re: Best water heater for house addition

Post by mgensler »

We recently redid the plumbing to our main bathroom an addition that the previous owners built. We had similar problems to what you are describing.

For maximum savings and minimum wait for hot water we did the following.

Replaced 3/4" cooper with 1/2" pex to the bathroom. Plenty of volume but much less cold water sitting in the hot pipe.

Installed a 240v 20amp thermostatic tankless under the sinks for instant hot water. Shuts off once the main hot water arrives.

We already had a tankless rennai gas heater for the whole house. Installed a 2.5 gal 120v electric tank right after the tankless. Provides much faster hot water while waiting for the tankless to fire.

Insulated all of the hot water lines.

Good luck!
Topic Author
28fe6
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Re: Best water heater for house addition

Post by 28fe6 »

So you have 2 tankless heaters, plus a tank-type heater?

I'm not saying it's a bad idea, just a little complicated. It seems like everyone who wants good hot water has to do some kind of complicated setup like this.

A big tank-type heater in the existing location, maybe with recirculation, seems like a pretty straightforward solution without having 2 or 3 heaters to maintain. The problem in my case is that I don't have a lot of space in the garage for a much bigger unit.

I have hard water and previous experience with tankless heaters. Tankless is not my first choice.
inverter
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Re: Best water heater for house addition

Post by inverter »

Highly recommend a tanked heat pump hot water heater. They are the most efficient by a 200-300% margin.

Recirculation sounds like a great idea. There is a new generation of recirculates that use buttons or motion sensors, instead of timers, so that they aren't moving hot water around when you aren't at home, like Act D'Mand (https://gothotwater.com).
mgensler
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Re: Best water heater for house addition

Post by mgensler »

28fe6 wrote: Thu Sep 22, 2022 8:23 am So you have 2 tankless heaters, plus a tank-type heater?

I'm not saying it's a bad idea, just a little complicated. It seems like everyone who wants good hot water has to do some kind of complicated setup like this.

A big tank-type heater in the existing location, maybe with recirculation, seems like a pretty straightforward solution without having 2 or 3 heaters to maintain. The problem in my case is that I don't have a lot of space in the garage for a much bigger unit.

I have hard water and previous experience with tankless heaters. Tankless is not my first choice.
Yes. The rinnai gas tankless was existing. The others cost just a few hundred dollars. We did this to forgo the losses from recirculating pumps. Those costs can really add up unless you install a motion detector. But again more equipment to maintain.

If hard water is an issue, then maybe checkout water softeners. We have one of those as well.
HomeStretch
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Re: Best water heater for house addition

Post by HomeStretch »

+1 to talk with a plumber.

Adding a recirculating system should make a significant difference in your wait time for hot water (it did in our case). Not to mention the water savings.
carne_asada
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Re: Best water heater for house addition

Post by carne_asada »

Insulating your pipes should help allot with the wait time. Also if you actually time the wait, its usually not that long, it just feels like it takes forever. Tank size should be a factor of family size and expected concurrent usage.
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TomatoTomahto
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Re: Best water heater for house addition

Post by TomatoTomahto »

inverter wrote: Thu Sep 22, 2022 9:14 am Highly recommend a tanked heat pump hot water heater. They are the most efficient by a 200-300% margin.

Recirculation sounds like a great idea. There is a new generation of recirculates that use buttons or motion sensors, instead of timers, so that they aren't moving hot water around when you aren't at home, like Act D'Mand (https://gothotwater.com).
OP doesn’t have a lot of space, and one thing a heat pump water heater needs is a lot of space where the cooled air can go (unless it’s vented outdoors). Our stupid plumber installed one that we had to get rid of because it cooled the air (and indirectly the water in the pipes) and was a complete failure except on very hot summer days.
I get the FI part but not the RE part of FIRE.
inverter
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Re: Best water heater for house addition

Post by inverter »

TomatoTomahto wrote: Thu Sep 22, 2022 5:57 pm
inverter wrote: Thu Sep 22, 2022 9:14 am Highly recommend a tanked heat pump hot water heater. They are the most efficient by a 200-300% margin.

Recirculation sounds like a great idea. There is a new generation of recirculates that use buttons or motion sensors, instead of timers, so that they aren't moving hot water around when you aren't at home, like Act D'Mand (https://gothotwater.com).
OP doesn’t have a lot of space, and one thing a heat pump water heater needs is a lot of space where the cooled air can go (unless it’s vented outdoors). Our stupid plumber installed one that we had to get rid of because it cooled the air (and indirectly the water in the pipes) and was a complete failure except on very hot summer days.
Weird, as even the Rheem documentation for a 50 gallon shows you only need 700 cubic feet. Where did you put it? The temperature and humidity will be lower in the immediate environment, but that's often a pro in many places, like a garage.
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TomatoTomahto
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Re: Best water heater for house addition

Post by TomatoTomahto »

inverter wrote: Thu Sep 22, 2022 7:32 pm
TomatoTomahto wrote: Thu Sep 22, 2022 5:57 pm
inverter wrote: Thu Sep 22, 2022 9:14 am Highly recommend a tanked heat pump hot water heater. They are the most efficient by a 200-300% margin.

Recirculation sounds like a great idea. There is a new generation of recirculates that use buttons or motion sensors, instead of timers, so that they aren't moving hot water around when you aren't at home, like Act D'Mand (https://gothotwater.com).
OP doesn’t have a lot of space, and one thing a heat pump water heater needs is a lot of space where the cooled air can go (unless it’s vented outdoors). Our stupid plumber installed one that we had to get rid of because it cooled the air (and indirectly the water in the pipes) and was a complete failure except on very hot summer days.
Weird, as even the Rheem documentation for a 50 gallon shows you only need 700 cubic feet. Where did you put it? The temperature and humidity will be lower in the immediate environment, but that's often a pro in many places, like a garage.
It was in a utility room. We have 3 ground sourced and 2 air sourced heat pumps at our house, so I'm generally a big fan of heat pumps. Ours was a larger water heater and the space was insufficient. I never used that plumber again.
I get the FI part but not the RE part of FIRE.
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