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Heat-pump water heaters, or HPWHs, are gaining popularity because they can provide ample hot water with low operating costs and a lifespan comparable to other tank-style water heaters. But this relatively new technology has a few quirks, and poor design and installation practices can lead to complaints about noise, comfort, and insufficient hot water.
As an installer and project manager, I’ve been involved in dozens of HPWH installations. Here I’ll describe how HPWHs work and answer some frequently asked questions to help you select the right one and optimize its performance.
How Much Does a HPWH Cost?
HPWHs cost more than electric-resistance or gas-fired tanks. A 50-ga. model starts at around $1600; 80-gal. models can cost upwards of $2700. Labor and additional materials typically run between $1500 and $3000. Factors affecting installation cost include whether a new electric circuit is needed and the difficulty of running drainpipe for the condensate, which is produced as the HPWH absorbs heat from the air.
The up-front costs of HPWHs can be offset by a 30% federal tax credit (up to a maximum credit of $2000) and, in many areas, state and utility incentives. The Energy Star program provides the HPWH Product Finder, a searchable database of more than 300 eligible models, along with information on rebates by zip code.
My utility offers $700 toward the installation of a qualified HPWH. Combining this incentive with the federal tax credit would bring the net cost of a HPWH installation from $4600 to $2730. With a net cost in the same range as other water-heating options and a lower operating cost, a HPWH can make good economic sense.
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3 Comments
I personally installed the 50 gallon AO Smith 240 V heat pump water heater about 6 years ago. I got it for $500 as a scratch and dent from Lowes and installed it myself. It has been fine. Very efficient. We have not had issues running out of hot water, although we use low water use shower heads.
A few things to keep in mind:
The system does dehumidify somewhat in summer (but not enough to replace a dehumidifier) and produces cool air in winter so be careful where you install it. Also it is loud so best to install in the basement. You do need an area with enough air flow so installing it in a closet with a solid dor will likely not work.
The actual installation is no different than installing any electric resistance hot water heater except that you have condensate lines that need to run to a drain or slop sink. I do not understand why it costs on average $1000 more to install than a resistance model costs. This makes no sense and makes these questionable from an economic point of view for those who cannot self install . I also don't understand why the unit costs more than twice what a resistance hot water heater costs. Think of it as a resistance hot water heater with an air conditioner on top. The air conditioner should not cost $1200. I think the price point on these may be the classic case of private industry raising prices to capture government subsidies- as I think these are overpriced by about the same amount as the subsidy. Perhaps the warranty issues add to the price. Either way, cost makes these less competitive from a purely economic point of view and you might be better spending these dollars on other energy efficiency measures (say additional PV panels or insulation). That is hard to say.
As seen in this article, there is an air filter that needs to be cleaned periodically. Takes two seconds. Also, like all hot water heaters with a tank, you should drain them periodically to clean them out...unless you have crystal clear water. I have a well system and calcium gunk from the water softener (or despitethe water softener?) builds up in the bottom so I drain it once a year. Also, filtering your water if it is unusually full of sediment, hard minerals or other stuff may be a good idea overall.
I have a Rheem unit that I installed in my garage. The air filter (same as shown in the picture in the article) is not particularly high quality. Given the potentially dusty environment and the air intake port on the Rheem being a standard duct size, I added an intake duct with a box for a higher quality air filter (I'm using a Merv 8). The idea being to keep the heat exchange coils cleaner and hopefully extend the life of my unit, I also sized the filter up to minimize the pressure drop.
Another option is the 240 V models that only require a 15 A circuit. That gives you faster recovery than the 120 V unit while using less electric capacity than the standard 30 A circuit models. And you if you have a dedicated 120 v circuit available, you can easily converter it to 240 V.
But they haven't turned out to be popular and thus are a little harder to find.
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