All of the 120v come with an internal mixing valve, and many of the 208/240 also do. The recovery for the 120v with a mixing valve is actually far quicker than for the 208/240 without mixing valve, because of the 140 degree water. You definitely do NOT need an 80 gallon tank if you go with the 120v with mixing valve. When comparing WH, don't equate electric and HP water heaters. They both use electricity to heat the water, but an electric resistance WH has a COP between 0.7 and 0.95, while most 208/240 HP WH exceed 3.5; even the 120v HPWH's have a COP of around 3.This is interesting info. I didn't know they came with an internal mixing valve. I see that several of the Rheem models have HydroBoost, but not all of them. The only way we would come out ahead financially is to set it to HP only mode. Our electric rates are over $0.33334/kWh. Not planning on doing anything in our house at this time anyway, but electric water heating would be unbelievably expensive compared to gas or oil. My impression from speaking to some pros on heatinghelp.com is that you need to get the 80 gallon version if you're going to keep it in HP mode because it just takes too long to get back up to temperature and you might risk running out of hot water if you like to take long showers. Plugging in our gas rate of $2.0059/therm, to the calculator I linked to above, we would save about $22/yr with the HPWH. Home Depot is showing the price difference to be about $2k in our area. The rebates cut that down somewhat, but after 10 years, gas still looks cheaper. I don't know the OP's rates or if he has enough space to install the 80 gallon in his attic.The prices you are being quoted don't make sense.
The amount of work in installing an electric heat pump WH is very similar to installing an electric resistance WH. The one exception is if there is some reason the supply or return of the HP WH needs to be vented - such as if the room in which the WH is being installed is too small. This occurs but is rare, and you can often deal with this by installing a louvered door on the room.
After install, the diffrence is in the cost of the unit itself. HP WH's cost abotu $1k more, but that is more than made up for in rebates, as well as operational savings.
Most HP WH's are programmable, so you can set them to heat the tank to x during the day when you have excess solar, and then set them to not heat outside your set times. You may have to experiment a bit with the settings and your household HW demand to get this right. Your hot water would probably only lose about 2 degrees in 14-16 hours without additional use.
Another option is 120v HP WH. The benefit to them is you don't need to run a new circuit. An added benefit is most have an internal mixing valve, and are designed to keep the tank at 140, then deliver 120 or so water via the mixing valve. The water in the tank retains usable temp over more use because it starts out hotter. The reaons the 120v HP tanks work like this is it takes longer for a 120v HP to heat the water than a 208/220. You may find a 120v HP WH in closer to the form factor you are seeking.
Beyond water heating, HP WH's act as a dehumidifier. This can be especially beneficial in humid climates. They will also cool the room they are in, because they remove heat from the surrounding air to heat the water.
Of course the biggest benefit to a HP water heater is they operate so efficiently. Most HP WH's have a COP of 3-4, meaning for each unit of energy they consume they use they produce 3 - 4 units of heat. Compare that to your standard B vented gas WH, with a COP of around 0.67, meaning for each unit of energy it consumes, it produces 0.67 units of heat.
Statistics: Posted by Saving$ — Sat Oct 19, 2024 12:56 am — Replies 37 — Views 1767