Heat Pump Water Heaters

Diagram of how a heat pump water heater works

How They Work

Heat pump water heaters (HPWH) are electric appliances that heat water by absorbing heat from the air and moving it into a storage tank, as opposed to generating heat through burning fossil fuels or resistance heating.

A heat pump water heater is very much like a refrigerator running in reverse: instead of pushing heat out of the inside of the refrigerator into its surroundings, a heat pump water heater absorbs heat from surrounding air to heat water.

how a heat pump water heater works

Since it takes far less energy to move heat than it does to create heat, heat pump water heaters are much more efficient than conventional water heaters: heat pump water heaters offer 250-300+% water heating efficiency compared to 60-70% for fossil fuel storage water heaters and 90-95% for traditional electric water heaters.

Heat pump water heaters heat water slowly over the course of the day and typically have a backup electric heating element to help speed up water heating during periods of high hot water demand.

Heat Pump Water Heater Options

Unlike air source and geothermal heat pumps, there are a more limited number of options for heat pump water heaters. HeatSmart CNY installers are offering a few sizes of heat pump water heaters depending on your building's hot water demand.

In general, 50-gallon heat pump water heaters are well-suited for households of 2 or maybe 3 occupants. Households with 4 or more occupants will typically need a 80-gallon heat pump water heater.

A few models are more similar to air source heat pumps with an outdoor unit that uses heat in the outdoor air to heat water, though these models are not being offered by HeatSmart CNY installers.

A heat pump water heater


Frequently Asked Questions

What are the benefits of installing a heat pump water heater?

Energy savings. If you heat with an electric, propane, or oil water heater (storage, on-demand/tankless, or combined with a boiler), you could save a couple hundred dollars a year on your water heating bill with a heat pump water heater, depending on how much hot water you currently use.

Dehumidification. Humidity can be an issue in many basements in Central New York. Heat pump water heaters dehumidify the space they're installed in, significantly reducing the need to run your dehumidifier.

Are there drawbacks to using a heat pump water heater?

Higher upfront cost. A heat pump water heater will cost more to install than a conventional water heater (~$1,000+). However, a $300 rebate from National Grid (if applicable) will help to reduce this added cost—and energy savings will pay for the added cost.

Noise. A heat pump water heater will be noisier than a typical water heater since the heat pump elements are located indoors. Heat pump water heaters typically make less noise than a window air conditioner and more than a refrigerator. Speak with your installer if you are sensitive to noise and vibrations to learn about your options.

Cooling effect. Heat pump water heaters extract heat from the surrounding air, cooling off whatever room it's in. If you install a heat pump water heater in a finished (heated) space, it will cool off the room and lead to a slight increase in space heating usage. If you install a heat pump water heater in an unfinished space, it will keep the space fairly cool year-round with lower impacts on space heating usage. In general the energy savings from a heat pump water heater will significantly outweigh any increases in space heating—and the added cooling and dehumidification may be valuable in the summer.

Is a heat pump water heat right for me?

There are two primary factors as to whether a heat pump water heater could be a good fit for your needs.

  1. Do you have a partially-finished or unfinished basement with enough clearance and airflow? Heat pump water heaters are taller than conventional storage tanks and need to be placed in rooms with at least 750 cubic feet of space (not mechanical closets) to ensure there is sufficient air flow for the water to be heated efficiently. Additionally, they should be placed in unconditioned or semi-conditioned (not directly heated) spaces to minimize the amount of heat the heat pump water heater uses that needs to be replaced by your heating system. If you have enough space next to your boiler or furnace (if you have one), a heat pump water heater will be able to take advantage of some of the waste heat generated.
  2. Do you use an electric resistance, oil, or propane water heater? A heat pump water heater could be an excellent investment for you if you are currently using a non-gas water heater, regardless of whether it is a storage tank, an on-demand/tankless system, or combined with your boiler. In general, most water heaters last 10-12 years, so if your water heater is approaching end of useful lifetime, consider replacing it with a high-efficiency model before it starts leaking.

A free site visit from one of the HeatSmart CNY installers can help you figure out whether a heat pump water heater is right for you.

How much can I save with a heat pump water heater?

How much you'll save will depend on a number of factors, including how much hot water you use, what your existing hot water heater and fuel type are, and where your heat pump water heater is located in your home.

A typical family of 4 will use approximately 70 gallons of hot water per day, based on estimates by New York State. The chart below shows estimated annual hot water heating bills for this typical family depending on heating fuel used.

water heater annual operating cost comparison

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