@wwhitney - The boiler heats water and sends it to the indirect storage tank (SuperStor) that has its own heat coil for maintaining the hot water. We're in cold country, so having the boiler as a backup for heating and potable hot water is a good to have as it takes little electricity to run. If grid is out for a while in winter, the heatpumps go off greatly increasing our off-grid run time. Hard to find people around here with experience on the Rheems; it's mostly oil/gas boilers or wood pellets.
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Natural Gas vs Heat pumps for heating
- Thread starter wwhitney
- Start date
FWIW, there is some discussion of adding a HPWH tank in series with an indirect tank here:
forum.heatinghelp.com
[There's some earlier discussion, but I think that was less on point.]
Cheers, Wayne
Add Heat Pump Water Heater to Existing Indirect Oil Boiler Hot Water
Hi! So, I have a Buderus G115/5 Oil Boiler that provides radiant heat to the house, as well as an integrated LT160/1 42 gal. indirect hot water storage heater.
forum.heatinghelp.com
[There's some earlier discussion, but I think that was less on point.]
Cheers, Wayne
I'm in New Orleans, so I've got experience with your climate. A high-efficiency heat pump is a great choice in our climate, far superior in efficiency to natural gas heat. (I'm not at all anti-gas, and I have two on-demand gas-fired water heaters and a gas dryer.) You want not just high SEER, but variable speed and inverter-driven, so the PW's can start the heat pump without any extra effort. If you're concerned about repairs to a variable speed, get a warranty. I'd also go with multiple systems, maybe one per floor. That way, when the one in your bedroom breaks, you've got other cool spaces in the house where you can sleep.
I looked at the Lennox XP25 to replace an old heat pump, and it's a great system. As others have said, a great installer is more important than a great system. The Lennox is too big for my space, though, so I got a Daikin Fit instead. I LOVE that unit -- the exterior is small like a mini-split, mounted high on an exterior wall, but it uses a conventional air handler and ducts inside. Speaking of ducts, do NOT put your ducts and air handler in a hot, unconditioned attic. And do not use any powered ventilators in an unconditioned attic -- they make almost everything worse, but contractors still think they help.
If you can find a roofer who's not doing roofs the way they were done 30 years ago, be sure they put 3/4 to one inch of rigid foam board outside of the roof decking, over areas that are conditioned like a conditioned attic or cathedral ceiling. That will eliminate most of the moisture/condensation/mold problems that tight new houses can have in our climate. But almost no one knows how to do this. And a n integrated dehumidifier like a Santa Fe will make the house much more comfortable.
I like what you said and I think you have hindsight which I can now benefit.
No doubt on a high SEER, variable heat pump system. Not sure why people are not using it more. Maybe AC companies are not pushing it for various reasons.
I mentioned before that I will have 3 separate heatpump systems, each one for attic, second floor and first floor. This allows for smaller versions of XP25 like 2 tons, 3 tons and 5 tons respectively.
I have looked at Matt Risinger video and learn about high performance houses. Santa Fe (previously Ultra Air) is something I will consider adding as well. It will allow the AC to last longer since it doesn't need to run the fan to reduce the humidity.
And while we are at it, why not add an air filtration system there as well.
Before this discussion, I plan to have a 2 tankless gas water heater with a recirculation pump. This seems like a go to way for most builders these days but I have looked into Rheem heatpump water heater and it seems like a better way to go. I'm thinking of getting a 80 gal one and put it in the attic. I have to talk to the AC company to see the load calculation.
For the garage, I plan to insulate and condition it with a minisplit AC. Having several Tesla and PWs in the garage it can be really hot in the Houston summer.
You raise a good point about the rigid foam on top of the roof decking. I don't think many builders do it for cost and lack of qualified crew. I definitely will discuss this with my builder to see if he can find a crew to do it.
In any case, my attic will be spray foam but it doesn't hurt to have better insulation.
One thing I'm curious if there is better way to do ducting. It seems like in 2021, people still using flex duct which can get dirty and air leak.
@EL0NTRK If you don't plan on living in the house very long, putting a water heater in the attic works. Personally, I think that it is a less than ideal location, especially for a HPHW heater, which is not exactly silent. But that is just me. I have been in more than a few otherwise quiet homes where the noise in the upper rooms (bedrooms) is the AC and hot water heater.
When the hot water heater leaks, and it eventually will leak, and needs replacing, it is a major hassle. I have had friends whose ceilings were shot, plus the carpets. Why not put it in the garage, help keep the electronics cool, and use a recirculating pump to get the hot water where you want it, when you want it?
I would also put your dehumidifier, whichever brand you go for, in a location where the noise won't affect anyone and it can be readily serviced. It has all the moving parts of a refrigerator or AC, and is likely to need repair/replacement on a five to ten year cycle, plus semiannual filter changes for many models.
All the best,
BG
When the hot water heater leaks, and it eventually will leak, and needs replacing, it is a major hassle. I have had friends whose ceilings were shot, plus the carpets. Why not put it in the garage, help keep the electronics cool, and use a recirculating pump to get the hot water where you want it, when you want it?
I would also put your dehumidifier, whichever brand you go for, in a location where the noise won't affect anyone and it can be readily serviced. It has all the moving parts of a refrigerator or AC, and is likely to need repair/replacement on a five to ten year cycle, plus semiannual filter changes for many models.
All the best,
BG
Rheem has a line of heat pump water heater with a leak detector and a noise level of 49 decibel which should resolve most concerns but i hear your points.
Are there other appliances we should look at to improve our carbon footprint and quality of life at the same time?
My wife and I went to look at cooking ranges the other day and I somewhat convinced her to seriously consider an induction cooktop instead of a gas one.
Are there other appliances we should look at to improve our carbon footprint and quality of life at the same time?
My wife and I went to look at cooking ranges the other day and I somewhat convinced her to seriously consider an induction cooktop instead of a gas one.
CrazyRabbit
Active Member
Then you will be "cooking on induction". need to change that saying to induction...
I think tankless with recirculation is not ideal. Recirculation would work better with a tank. I hear great things about heat pump water heaters, which should be excellent for our climate. As someone else said, put it in the garage to make use of that excess heat and cool the area down a bit.
The purpose of rigid foam board on top of the roof is to limit condensation on the underlying roof decking. If you have open cell foam in the attic, water vapor can pass through and condense on the wood, typically in spring and fall when the house is more humid because the HVAC isn't running as much. Adding the foam board on the outside prevents this. If you're using closed-cell foam in the attic, you won't have this concern. Green Building Advisor has some good articles on this issue, and you can look for articles by Joe Lstiburek, who's the consensus expert.
Tankless with recirculation works fine. I have three gas tankless in parallel on a recirculating loop in a 60,000 square foot building with no issues. The only problem is with the tankless heaters getting scaled up pretty quickly and requiring regular cleaning.
If I could overhaul the whole system (not my decision), we'd probably upgrade to two large heat pump water heaters in parallel - two 80 gallon Rheems would get the job done nicely.
We also have a gas tankless with our recirculation system and it works great. The main shower is hot in 10 seconds instead of 4 minutes. We have a water softener and no sign of scaling in 4 years. This should last longer than the tanks units which seem to start leaking at about 6 years.
Yes, my current house has a tankless gas heater in the garage and it takes few minutes for shower. We have no recirculation system. We have wholehouse water softener so it does not get scaled.
I like how a small footprint the gas tankless is but given it's gas, it's noisy and gas price is going up, I think with a solar system, it makes more financial sense and environmental sense to go with a heatpump water heater.
I think a 80gal should be enough for family of 5.
You referring to Rheem heat pumps for HVAC or hot water? I think the thread is about HwH but AO Smith and B-W (far as I know) only make HwHs.
charlesj
Active Member
Tank water heaters have a sacrifice rod that needs to be inspected yearly and replaced roughly in 3 years. I learned the hard way, now it is changed at 3 year interval and heater is still good after 9 years. Have a radiant system with its own yank heater, closed system, still good without changing that rod in 20 years.
nwdiver
Well-Known Member
These newer water heaters should throw a fault code when the rod is due for replacement. Heck... some of them could text you with a link to amazon...
Many, many more people utilizing resources that have grown only a bit
nwdiver
Well-Known Member
???? So having a wider variety of better options available due to new more affordable technology like VFDs and better refrigerants while also having the intellectual curiosity to explore these options.... to you... is 'regression'???
Definitely. I remember growing up in the Central Valley we paid $20/mo for all the water we could use. So my dad emptied the pool every winter so he did not have to buy expensive chemicals. After all whether we used 1,000 or 30,000 gals a month the bill was the same.
charlesj
Active Member
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