4 - Heat Pump Water Heater

Electrify Brookline | How-To Guide #4

If you’re a homeowner or landlord in Brookline, you probably have a hot water heater and it’s probably powered by gas. One of these days, you’ll need to replace it, as the average water heater lifespan is around 10-15 years. When you replace it, consider a heat pump water heater, sometimes also called a “hybrid” water heater.

What Is a Heat Pump Water Heater?

Heat pump water heaters (HPWHs) are electric appliances that provide hot water to your home. Unlike conventional gas or electric water heaters, they do not create heat, but rather they move heat from the air around the water heater into the water – like your refrigerator or air conditioner operating in reverse. HPWHs are extremely efficient, with lower operating costs than gas or electric water heaters.

How Can This Help the Climate?

In the average home in Massachusetts, gas hot water heaters are the second biggest contributor to household carbon emissions. HPWHs  produce lower emissions on today’s grid than a gas hot water heater, and with today’s electric grid getting greener over time, emissions will decrease as time goes on.

What’s Involved?

If your hot water heater is nearing the end of its life (10+ years old) you should plan ahead for its replacement. HPWHs need:

  • 240 volt, 30 amp or 15 amp electrical circuit for most models (future models may run on standard 120 volts).
  • Clearance both above and around the water heater to provide sufficient air space. HPWHs need to be located in a room, not in a closet.
  • A drain or other location to dispose of condensate (i.e. water).

For most of us in the Northeast, installing a heat pump water heater in the basement is ideal. That’s probably where your current hot water heater is now, and it’s usually best to put a replacement in that same position. Just be sure there is enough clearance as specified in the installation manual as HPWHs tend to be taller than what you may have now.

Plan for replacing your water heater before you are in an emergency situation with no hot water or a puddle of water leaking onto the basement floor. Research sizes and brands of HPWH, know what electrical upgrades may be needed, and verify that you have adequate space and clearances – this will help speed up the installation of a new HPWH.

What Choices Are There?

Manufacturers include AOSmith, Bradford, Rheem, and State. Heat pump water heaters come in various sizes, typically 40-, 50-, 65-, and 80-gallon tanks. Something to consider is getting the largest tank you can – that way, should anything happen to interrupt the ability to heat the water, you will have a larger reservoir of already heated water to carry you through until repairs can be made. In addition, a larger tank will enable the unit to operate at maximum efficiency.

You can find reviews of various heat pump water heaters here:

Other Considerations

  • One benefit of a heat pump water heater in your basement is that it helps to dehumidify air, but it can also make that space a bit colder. The HPWH will cool the air around it by 5-10 degrees F, and for this reason is usually placed in an area such as a basement where this isn’t a problem.
  • Heat pump water heaters can be noisy, so take care on where they are installed. Having them near a bedroom, for instance, can be a noise issue. When operating, they can be about as loud as a dishwasher running.
  • Many can be controlled from a smartphone.
  • Most units have an automatic leak detector. The best units can detect leaks anywhere in your home and help prevent water damage.
  • The only additional maintenance needed beyond a regular water heater is that you will need to periodically remove and wash the air filter with water and a mild detergent.
  • The heater will produce condensation while operating and this must be drained. If there is no floor drain nearby, an additional condensate pump will have to be installed.
  • Most of today’s HPWHs are hybrid models, as they have a conventional electrical heating method in addition to the heat pump technology that is used to heat the water. This can provide extra heat when needed.


Installation Costs: An HPWH unit and its installation may cost you more than a similar size gas or electric water heater and may also require electrical work; however, the price differential may be offset with available rebates and tax credits.

Operating Costs: HPWHs are extremely efficient with operating costs that can be up to 50% lower than the operating costs of an electric, oil, or propane water heater. Heat pump water heaters are robust, and can last much longer than conventional water heaters. A HPWH may cost more to install, but since it is 3 to 4 times more efficient, the savings in electricity will pay for the added cost in a few years.

Available Rebates and Tax Credits

The sponsors of Mass Save currently offer instant savings of $750 off the list price of an HPWH for residential customers that have a licensed plumber install a qualified heat pump water heater. Check Mass Save website for up-to-date information.

The newly passed Inflation Reduction Act (IRA) also includes rebates of up to $1,750 for heat pump water heaters, which will become available sometime in 2023-24. There may also be Federal tax credits. As these tax credits are constantly evolving, be sure to verify the latest information at Rewiring America.

How Your Brookline Neighbors Have Made the Switch

Story #1 – A North Brookline Homeowner

The existing hot water tank in this three-story Victorian had developed a crack and needed to be replaced. As someone who was very climate-focused, the owner wanted to replace it with the most climate-friendly option he could and focused on obtaining a heat pump water heater.

The owner had 200 amp service and did not need electrical upgrades. He found an installer he trusted and selected a Rheem HPWH with an 80-gallon tank. With their previous (natural gas) water heater, which was 50 gallons, the owner would occasionally run out of hot water. That never happens now, even when they have visitors.

Story #2 – A Homeowner Near Washington Square

The owner bought his current home about four years ago. At that time, everything – the heating system, the hot water heater, the clothes dryer – was powered with gas. His long-term goal was to electrify everything, and he’s actually completed that work – the gas service to his home has been completely turned off.

For his water heater, the owner chose the SANCO2 system (formerly called SANDEN), manufactured by a Japanese company. He purchased the system from 475 High Performance Building Supply, from Brooklyn, NY.

In this installation, the condenser is installed outside the house, while the tank itself is in the basement. The cost of the unit was about $5,500 – more expensive than other alternatives – but its greater efficiency and its use of CO2 as the refrigerant (CO2 has a lower global warming potential than other refrigerants) made the option appealing.

The "split" design of the SANCO2 HPWH is a feature that enhances the performance of the system. Traditional, integrated HPWHs, in which the compressor and the tank are co-located, draw heat from the interior of the building and therefore cool the interior year-round. The SANCO2 uses outside air instead, and the outdoor compressor can be as far as 50 feet from the interior tank. The homeowner has made several other related changes, including a system for returning warm water to the system as well as a backup electric option.

About Electrify Brookline

Electrify Brookline is a collaboration between the Town of Brookline’s Zero Emissions Advisory Board (ZEAB), Mothers Out Front Brookline and Climate Action Brookline.  Our goal is to provide clear information to guide the community on the path toward electrification — improving the energy efficiency, health and comfort of their living spaces while reducing climate-damaging emissions to preserve a livable future for all.

IMPORTANT: Verify with your installers that they have the proper licenses and insurance, and confirm that they have or will obtain all required permits and inspections from the Town of Brookline.

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