FAQs

Heat pumps use a highly temperature-sensitive refrigerant and a series of fans and compression and expansion valves to absorb heat and move from one place to another. Refrigerators and air conditioners use the same principles, but a heat pump can reverse the cooling process to provide heat in winter.

Yes, many heat pump models are built to provide 100% of New England’s heating needs. When you contact installers, request a quote for a “cold climate heat pump.” These models are designed to work efficiently in sub-freezing, even sub-zero, temperatures.

The size of your heat pump should be based on an accurate measurement of your home’s “heat load.” That’s the number of BTUs (British Thermal Units) of heat needed to keep the building cozy on the coldest winter nights. This measurement is called a “Manual J calculation.” When you meet with potential installers, ask them if they would perform a Manual J calculation or to explain how they would estimate your heat load. 

It’s important the installers do not oversize the equipment. Oversizing not only leads to higher installation and operating costs, but also to inadequate dehumidification in summer. You may be able to estimate your home’s heat load. This short video provides an overview of CoolCalc, a free software program that makes it easy for you to estimate your own home’s heat load: https://youtu.be/fnVZ884Tvdg.

You can find trusted installers through our partners at Heat Pumps: Get Advice and Shop Installers.

The cost of installing a whole home heat pump system in our region is averaging between $15,000 - $25,000, but the cost depends on what percentage of your heating the heat pump will provide, how large your home is, and how well-insulated it is. A heat pump for a relatively small, well insulated house might cost only $6,000, but a large, under-insulated home might cost $45,000.

Whether you will save money on heating costs depends on what you pay for electricity and for the fuel you’re currently using for heat. If you now use electric resistance baseboard, a heat pump will definitely save you money on operating costs. If you currently heat with oil or propane, heating your home with a heat pump will likely cost less. If you currently heat with gas, whether you save money will depend on the electricity and gas rates in your area. Starting November 1, 2025, all three major electric utilities in Massachusetts - Unitil, National Grid, and Eversource - will offer new lower winter electricity delivery rates for heat pump users. 

We recommend you consult with a building science expert from one of our partners to help you estimate relative costs based on the individual characteristics of your home, your current fuel and electricity costs, and other factors. 

You could also input your particular costs of electricity and the cost of your current method of heating into one or both of these interactive calculators: Mass Save | Heating Comparison Calculator and Residential Heating System Cost Calculator | Efficiency Maine.

Yes, if you already have ductwork for heating, you can likely plan to replace that equipment with a cold climate heat pump, pending an assessment of your existing ductwork. The heat pump can provide cooling as well as heating, giving you year-round comfort.  To read about a family that replaced its fuel oil forced air furnace HVAC system with air source heat pumps, go to Friedman Case Study_2.pdf (neep.org).

Yes, replacing your electric baseboard resistance heating system with heat pumps will save you money in winter because heat pumps are 2 to 3 times more efficient than electric baseboards. Heat pumps also provide efficient air conditioning with the same equipment.  To read about a homeowner who replaced her baseboard heating and window units with an air source heat pump, go to Nia's New Floor Mounted Air-Source Heat Pump - Massachusetts Clean Energy Center (masscec.com).

It is often possible to use existing ductwork with a heat pump, but you will need to have a professional inspect your home to confirm if your existing ductwork would be adequate for a heat pump.

Existing central A/C ductwork can often be used with a central heat pump, but you will need a professional assessment to confirm if that ductwork would be adequate.  In some cases, you might need to augment the central heat pump with one or more ductless heads.

Your boiler system was designed to use steam or very hot water – 180 to 200 degrees – to provide the heat needed to keep your home warm in winter. “Air-to-water" or “hydronic” heat pump technology is able to deliver water heated only as hot as 140 degrees. 

Converting your current hydronic distribution system to an air-to-water heat pump may be a good option if you already have radiant flooring, are able to add radiant flooring or wall radiators, or if you can increase your insulation and air-sealing. To find potential installers of air-to-water heat pumps, consult the Mass Save or Clean Heat Rhode Island website.

You can also replace your boiler or reduce the amount of time your need to rely on it by installing one or more ductless air source heat pumps. To read about homeowners who replaced their oil-fired boiler with air source heat pumps, go to Slack Case Study_4.pdf (neep.org).

If you have radiant floor heating already or are considering installing it, you could consider an “air-to-water” heat pump. Expect the process to take longer and the cost to be higher than the common air-to-air heat pumps, because, for now, there are not many installers in our region with experience installing these systems. To learn how air-to-water heat pumps work, go to 4BED0381F5C1422085B90A7C8A864B4B.ashx (masssave.com).

You can! Mass Save and other energy efficiency programs incentivize the use of a “smart control” thermostat to seamlessly toggle between the current system and the heat pump. Your heat pump installer will program the new thermostat with a specific set point – often around 30 degrees – above which the heat pump works and below which your current system turns on and the heat pump turns off.

The smallest capacity heat pumps produce 6,000 BTUs, roughly enough to heat a room about 15 ft x 20 ft., or about 300 square feet. If you have multiple small rooms next to each other, you might be able to use one head with short duct runs to serve those adjacent rooms. Depending on how a small room is used and how much heat it needs, you might be able to warm it sufficiently with a small strip of electric resistence heat or with a dual-hose portable heat pump or a window a/c with heating capacity. For more information on heat pumps for small spaces, see this 2023 webinar: Micro Heat Pumps - Window, Portable and Saddleback - YouTube.

The average lifespan of an air-source heat pump is about 15 years.

Ground-source heat pumps are generally more efficient than air-source heat pumps, and thus have lower energy demand and lower operating costs. They are more expensive to install, however, and not all properties are appropriate for ground source heat pumps.  A professional would need to inspect your property to determine if the installation of a ground-source heat pump is possible.  For more information on ground source heat pumps, go to Ground-Source Heat Pumps - Massachusetts Clean Energy Center (masscec.com).

A heat pump condenser (the outdoor unit) needs air flow in all directions. It is generally placed a foot away from the house and needs a foot clearance from the ground and any landscaping. It can be placed on or under a porch. It should not be put under a roof overhang where falling snow or icicles might damage it. The condenser can be up to 150 feet away from all indoor units.

You would need to work with your condo association to identify an appropriate place. Condensers can be located on or under a deck or on the roof.

You may need to upgrade to a 200-amp service to support heat pumps. Many older homes have only 100 or 60 amp service. If you're not sure what you have, check the main electrical shut off switch to see if there is a number embossed in the switch. Ask your electrician about an upgrade and if there are other ways to manage the various electrical devices in your home to avoid an upgrade. If you do need to upgrade your service and your main shut off switch and panels are currently in your basement, you will likely have to move those to a location on an outside wall (to meet modern fire codes). 

All modern furnaces and boilers rely on electricity in some way, so fossil fuel heating is no more reliable in a power outage than an electric heat pump would be. Heat pumps can be powered by a generator or by battery backup systems. Some consumers have chosen to have a wood stove as a back-up for power outages.

Most LG and Samsung equipment have wifi built in. For equipment from other companies, such as Mitsubishi and Fujitsu, a wireless module can be added to the unit, for approximately $250/unit.

Residents can easily clean the filters on the indoor units. Do this at least every season according to the owner’s manual. For the outdoor unit, remove leaves and snow from all sides. No other regular maintenance is required.

Heat pumps are vulnerable to mold in a way similar to all air conditioning systems. Warm air is pulled into the machine, then as heat is extracted, some of the moisture in the air, along with whatever microscopic impurities floating in the air, clings to the inside of the machine. Water is constantly being drained to the outside during cooling mode.

To prevent any mold growth during the cooling season, if the outdoor temperature is such that you do not need your heat pump to actively cool your home, switch the setting from cooling mode to fan only. That air flow will completely dry out the internal components and prevent mold proliferation.

If you see dust or mold in your indoor head, schedule a professional deep cleaning (which should be comparable in cost to an annual furnace tune-up).

This video by a heat pump expert offers a longer examination of this issue, Should I be worried about moldy mini splits (youtube.com).

Yes! A federal tax credit of $2,000 is available for installations of heat pumps made before Jan. 1, 2026. You can claim an additional $600 for upgrading your electric panel. Find more details at Home Energy Tax Credits | Internal Revenue Service (irs.gov).

If Massachusetts receives federal funding for heat pump rebates (funding has been allocated but may not be delivered), the Commonwealth intends to direct those funds to communities served by municipal power plants, as well as to extend other channels that are already served by existing programs. You can sign up to receive updates about Massachusetts roll-out of the IRA rebate program at: Sign up (e2ma.net)

In Rhode Island, you can see if you qualify for rebates at Homeowner - Clean Heat Rhode Island. In addition to Clean Heat Rhode Island, some consumers may qualify for additional incentives from their utility company. See this page for the appropriate links: Clean Heating & Cooling Incentives | Rhode Island Office of Energy Resources.

The Mass Save heat pump incentive is capped at $10,000 per home or apartment for air-source and $15,000 for ground-source. For more information on air-source heat pump incentives, go to Mass Save | Air Source & Air to Water Heat Pumps.  For more information on ground-source heat pumps, go to Mass Save | Ground Source Heat Pumps. 

Rhode Island’s rebates depend on the type of heating the homeowner is displacing and other factors. For more information on the incentives that Rhode Island offers, go to: Clean Heating & Cooling Incentives | Rhode Island Office of Energy Resources.

In Mass Save territory, homeowners are required to use a member of the Mass Save Heat Pump Installer Network for their heat pump projects to receive a rebate.  To find installers who serve Massachusetts, go to Mass Save | Heat Pump Installer Search.

For Rhode Island, you must use one of the installers on this list of participating installers: RIE-Participating-Contractors-1625.ashx

For homes in communities served by a Mass Save sponsor, you can email your rebate question to customer service at Contact Us | Contact Mass Save® | Mass Save

In Rhode Island, you will submit a proposal to CleanHeatRI before the heat pump is installed so you can know for certain what your incentive would be.

If you live in Rhode Island, you may be eligible for a zero-interest loan of up to $25,000 for approved high-efficiency heat pump systems that are displacing electric, oil, or propane heating systems.  To start the process, you need to call EnergyWise at 888-633-7947 to schedule a no-cost home energy assessment. 

For Massachusetts residents, Mass Save offers zero-interest financing opportunities for energy-efficient home upgrades, including up to $25,000 for the installation of air source and ground source heat pumps.  For more information, go to Mass Save® Heat Loan | Energy-Saving Loan Program.

Massachusetts Community Climate Bank offers low-interest energy efficiency loans of up to $100,000 to households with incomes up to 135% of AMI. For more information, go to Energy Saver Home Loan Program (masshousing.com).

In a condo association with separate heating systems for each apartment, each unit may apply for a heat pump rebate.  Condos with shared heating systems would need to apply to the multi-family program, which has a different incentive structure. See Mass Save | Multi-Family.

Mass Save offers an instant $750 rebate for qualified heat pump water heaters that are purchased from participating distributors.  For more information on heat pump water heaters, go to Heat Pump Water Heater Rebates (masssave.com).  The list of participating distributors can be found here: Master-Participant-Contact-List---HPWHs.pdf (masssave.com).

Rhode Island offers a $600 rebate on heat pump water heaters. The rebate form can be found here: Residential_Heat_Pump_Water_Heater_Rebate-Form_2025.

The Inflation Reduction Act also incentivizes heat pump water heaters. The $2,000 federal tax credit for heat pump water heaters remains in effect until January 1, 2026.

Eligibility for rebates and incentives are determined by installation date, not purchase date.

In most cases, rebates are paid to the homeowner, not the installer, but your installer may be willing to fill out and submit the rebate application for you, if you have signed the forms yourself.

To confirm that the heat pump equipment that your installer is proposing to install qualifies for Mass Save incentives, go to Heat Pump Qualified Product List (HPQPL) where you can search qualified equipment by brand and model number.  You can also download a spreadsheet with the entire list of eligible heat pumps and search for the equipment. Clean Heat RI can help Rhode Island residents confirm whether or not proposed equipment would qualify for rebates.

Residents can easily clean the filters on the indoor units. Do this at least every season according to the owner’s manual. For the outdoor unit, clean leaves and snow away from all sides. No other regular maintenance is required.

Heat pumps are vulnerable to mold in a way similar to all air conditioning systems. Warm air is pulled into the machine, then as heat is extracted, some of the moisture in the air, along with whatever microscopic impurities floating in the air, clings to the inside of the machine. Water is constantly being drained to the outside during cooling mode.

To prevent any mold growth during the cooling season, if the outdoor temperature is such that you do not need your heat pump to actively cool your home, switch the setting from cooling mode to fan only. That air flow will completely dry out the internal components and prevent mold proliferation.

If you see dust or mold inside your indoor head, schedule a professional deep cleaning (which should be comparable in cost to an annual furnace tune-up).

This video by a heat pump expert offers a longer examination of this issue, Should I be worried about moldy mini splits (youtube.com).

Generally, heat pumps work most efficiently at a steady temperature.  Turning a heat pump down when you're away or asleep may actually use more energy than leaving it on, because it has to work harder to come back to the desired temperature than it does to maintain it.  This is why most heat pump experts suggest that consumers “set it and forget it.”

If you have a heat pump with the capacity to gradually return to ideal temperature after a set-back, BetterBuilt NW suggests no more than a 2 degree set-back for nights or if no one is home for more than 6 hours during the day. If you are going to be away from home for at least 48 hours and you are able program your thermostat to increase the temperature just 2 degrees every hour, then you could potentially save energy with a 5- to 8-degree set-back. 

On mild summer days when you expect to need no air conditioning for at least 6 hours, you may save energy by switching your heat pump to the fan setting for 30 minutes and then shutting it off completely. When you turn it back on, set the cooling temperature to the outside temperature, then gradually reduce the cooling temperature every hour by a couple of degrees, until you reach your desired cooling temperature.

This article provides a case study with some data confirming the “set it and forget it” advice for heat pumps: Set It & Forget It: How Heat Pumps Resolved a Long Term Marital Dispute - CleanTechnica.

Starting November 1, 2025, all three major electric utilities in Massachusetts - Unitil, National Grid, and Eversource - will offer new lower winter electricity delivery rates for heat pump users. If you received a heat pump rebate through Mass Save, you should be automatically enrolled in the new rate, but you should call your utility provider in October to confirm. If you did not receive a Mass Save rebate for your heat pump, you’ll need to call your utility and ask to be enrolled.

There are a few measures you can take to optimize the efficiency of your heat pumps. Our thanks to Heat Pump User Tips - Efficiency Maine for many of these tips.

If your system is having performance issues, do not use “economy” mode (not all systems have this option). “Economy” mode caps the power of the heat pump at 70% of its capacity.

Check the batteries in your remote, if the batteries are drained, the remote may not be properly communicating with the air handler, also known as the head.

Leave your heat pumps running at a constant temperature (“set it and forget it”).  Big temperature adjustments when you’re away for short periods or asleep could use more energy than leaving the thermostat at a steady setting. This is because the heat pump has to work harder to come back to the desired temperature than it does to maintain it.

If you won’t need cooling or heating for 48 hours or more, turn off the system. Use “fan” mode when transitioning from “cool” to “off’ to prevent mold growing in the head. Running in fan mode before turning off allows the interior cooling elements to come to room temperature and dry out. The head uses very little power on a low fan setting, so it’s fine to leave the fan on for multiple hours. 

When you turn on a heat pump, adjust the temperature gradually; for example, in summer start 6 degrees hotter than your target temperature goal and decrease the temp a degree or two every hour.

Match the summer mode to your needs. “Fan” uses the least energy and may suffice when you need only a little temperature control. When it’s warm and muggy, “dry” mode reduces humidity and makes higher temperatures feel more comfortable. Use “cool” mode when “fan” and “dry” are not adequate for comfort.

Avoid “auto” mode, which allows the heat pump to alternate between the “cool” and “heat” modes to maintain a constant temperature. 

Optimize air flow direction. To maximize reach, air should be directed toward the open space that is the farthest away from the head, and away from any obstructions.

Clean your dust filters. As directed by your user manual, vacuum or rinse the dust filters in the head when they become visibly dirty or when the indicator light comes on. The frequency of cleaning can range from weeks to months depending on use and dust volume.

Follow your heat pump manufacturer’s recommendations for professional cleaning in addition to regular dust filter cleaning.

Keep your outdoor units clear of shrubs, leaves, snow drifts, and any other obstructions.

Just like an air source or ground source heat pump (and like an air conditioner or refrigerator), a heat pump water heater (HPWH) transfers heat from one place to another. In the case of a HPWH, heat is transferred from the space surrounding the unit, to the water in the unit’s tank. If the air temperature goes below 37 degrees or if your family uses a lot of hot water at once (like taking several showers in a row), there is a back-up electric resistance mechanism, so you don’t run out of hot water.

Yes, because the unit does not create heat, but instead transfers it from one place to another, it is three to four times more efficient than other types of water heaters.

Yes, but luckily there are financial incentives to assist you in purchasing a HPWH.

MassSave offers a $750 rebate for installing a HPWH, https://www.masssave.com/residential/rebates-and-incentives/water-heating/water-heaters/heat-pump-water-heaters. Similarly, Clean Heat Rhode Island also offers a $750 rebate, https://cleanheatri.com/resources/incentives, for residents replacing an oil, propane or natural gas water heater. For residents replacing an electric resistance water heater or for new construction, Rhode Island Energy also offers a $600 rebate, https://www.rienergy.com/RI-Home/Energy-Saving-Programs/rebate-programs. In addition, the federal Inflation Reduction Act provides a federal tax credit of 30% of the net cost of the HPWH (after applying the rebate), up to $2,000. The federal tax credit for heat pumps and HPWHs is limited to a total of $2,000/year, not $2,000 for each.

Compared to an electric resistance water heater, a HPWH is much more economical to run, and a HPWH is likely to be less expensive than propane and oil-fired hot water systems. Depending on electricity and gas rates, a HPWH may be only slightly more expensive to run than a gas-fired water heater. To determine the cost to run a HPWH based on your utility rates, go to Residential Water Heater Cost Calculator | Efficiency Maine.

While 120 volt HPWHs are being manufactured and used in some parts the country, in cold climates, such as the Northeast, 120-volt HPWHs are not yet commonly available, and are not recommended due to the cold temperature of our input water.

This depends on the electric load of your household—that is, the other electric appliances you run, the amount of electricity they use, and how often you use them.

 However, because eventually we will all be using all-electric appliances as we shift away from fossil fuels, it may make sense to upgrade your electric service to 200 amps, if you haven’t already done so. 

For projects completed by Dec. 31, 2025, the Inflation Reduction Act provides a tax credit of up to $600 for upgrading your electrical service if you do so in conjunction with installing a heat pump or HPWH. https://homes.rewiringamerica.org/federal-incentives/25c-electrical-panel-tax-credits 

Clean Heat Rhode Island offers a $500 rebate to upgrade electrical service https://cleanheatri.com/resources/incentives/ Incentives - Clean Heat Rhode Island (cleanheatri.com) 

Massachusetts Community Climate Bank offers low-interest loans for energy efficiency projects including electrical service upgrades to qualified residents: https://www.masshousing.com/mass-community-climate-bank/energy-saver-home-loan? Energy Saver Home Loan Program (masshousing.com)

Because a HPWH requires air flow for the transfer of heat, generally a HPWH is installed in a space of at least 750 cubic feet. However, if the only space you have is a small closet, there are two measures you can take that might allow placement there: (1) installation of a louvered door on the closet or (2) placement of a duct from the compressor of the HPWH to a larger room that will permit air to flow between the two. We recommend discussing this with your installer.

Because the HPWH is drawing heat out of the basement, you will see a small drop in temperature of a few degrees and this will cause the heat pumps to have to work a little harder.

For a webinar presentation about heat pump water heaters, we recommend: Getting to Zero 2024: Heat Pump Hot Water Heaters (youtube.com).

We also recommend visiting this Mass Clean Energy Center site: Heat Pump Water Heater - Massachusetts Clean Energy Center (masscec.com).