My basement has R20 foam over most of the wall area. It also has fiberglass in the ceiling (original with house). Would a heat pump water heater work well there?
Does a Heat Pump Water Heater Work Well in an Insulated Basement?
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Clarkbug
Minister of Fire
It's not, really. But there is an oil boiler and, at some point 
, a pellet boiler. The floor is exposed concrete.
, a pellet boiler. The floor is exposed concrete.
My Geyser works in a below ground basement. In the depth of winter, it draws heat from the oil burner which runs on the coldest nights and from the ground heat seeping in through the basement floor and walls. It does run for much longer periods and it's efficiency is well down but keeps our DWH hot. It has low spare heat capacity and so we turn on the old oil DHW heater as backup if we have house guests.
If you have a source of heat for the basement air that will replace the heat pulled out and put into the DHW, then it will work. Otherwise probably not.
If you have a source of heat for the basement air that will replace the heat pulled out and put into the DHW, then it will work. Otherwise probably not.
The major question is: What are current minimum winter temps and total square footage?
If it is a big space, it might pull the temp down only a couple degrees. Most HPWH switch to coils between 45 and 50°F air temp (I think the GE model is 50). So, to be conservative, I'd figure any month the basement currently runs under 53-55, the HPWH would run conventional electric.
To get technical, if the slab is not insulated and you have a boiler down there, my guess if you are making BTUs and dumping them to the earth. In this case, the HPWH pulling a few will not make much difference. If it were a superinsulated box running 55°F in the winter, that would be a problem.
If it is a big space, it might pull the temp down only a couple degrees. Most HPWH switch to coils between 45 and 50°F air temp (I think the GE model is 50). So, to be conservative, I'd figure any month the basement currently runs under 53-55, the HPWH would run conventional electric.
To get technical, if the slab is not insulated and you have a boiler down there, my guess if you are making BTUs and dumping them to the earth. In this case, the HPWH pulling a few will not make much difference. If it were a superinsulated box running 55°F in the winter, that would be a problem.
I'm thinking the pellet boiler would provide dhw during the winter and maybe shoulder months and the heat pump for the summer, and again, maybe shoulders. Could the wall insulation pose an issue even then, cooling down the basement even more? If things cool down too much, could there be condensation issues, even with the dehumidification effect?
If your slab was insulated too, I would worry, but then you would just pull out the basement ceiling insulation, and get free AC.
IMHO, if the slab is uninsulated you are not going to chill it that much with a HPWH. I assume you are well airsealed down there.
But if you are airsealed and have insulated walls, why not pull out the ceiling insulation...what is it doing for you?...you could leave it and IF you had a problem then pull some of it out.
IMHO, if the slab is uninsulated you are not going to chill it that much with a HPWH. I assume you are well airsealed down there.
But if you are airsealed and have insulated walls, why not pull out the ceiling insulation...what is it doing for you?...you could leave it and IF you had a problem then pull some of it out.
I hate the insulation, of course. Anytime I do anything overhead I breathe in that crap or get it in my eyes. And, it's at that point that I figure it'd be worthwhile to put on a little personal protection equpment. On the other hand, we've had guests come over and ask if we have floor heat because their feet aren't cold at all on the wood floor. Well, maybe one guest, anyway. The space is always cooler than upstairs. I can't see going out of my to pull it out. I'm not sure I'd get a hybrid water heater if I had to. These are the kinds of things I'd like to get a handle on before taking the plunge.
I guess what I am trying to say if you have a large space with an uninsulated slab, and you only want to use it in the summer (and shoulder seasons), I am confident (as a random stranger on the internet trying to spend your money) that it will work fine. and you will be perfectly satisfied. Period. I am also fairly confident that it will work part time in the winter with parasitic heat from a boiler(s).
But that in addition to my **opinion**, risk is reduced by the fact that you would have options. If there was more cooling that you wanted, you could lose part of the (obsolete) insulation your basement ceiling. If the walls are so well sealed and insulated, you might just get a warmer basement (and still have warm first floors) if you pulled that chit.
And look for a rebate to get it nearly as cheap as a conventional tank. A no brainer.
But that in addition to my **opinion**, risk is reduced by the fact that you would have options. If there was more cooling that you wanted, you could lose part of the (obsolete) insulation your basement ceiling. If the walls are so well sealed and insulated, you might just get a warmer basement (and still have warm first floors) if you pulled that chit.
And look for a rebate to get it nearly as cheap as a conventional tank. A no brainer.
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