When you start researching your heat pump options

How do heat pumps work?

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.

Can heat pumps really provide enough heat to keep us warm 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.

How do I determine what size heat pump I need?

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.

How can I find a trusted installer?

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

How much do heat pumps cost to install?

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.

Will a heat pump increase my heating costs?

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. 

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 this interactive calculator from Efficiency Maine: Residential Heating System Cost Calculator | Efficiency Maine.

My home has a hot air furnace. Can I replace this with a central heat pump?

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).

My home has electric baseboard heating and I use window units for air conditioning or have no air conditioning. Can I save money by replacing both with heat pumps?

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).

My home has central air conditioning. Can I add a heat pump?

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.

I have a boiler and central A/C. Can I replace both pieces of equipment with 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.

My home has a boiler and no ductwork. Can I replace my boiler with a heat pump?

For now, there are no simple heat pump replacements for boilers. Unless you increase your insulation or add wall radiators, currently available air-to-water heat pumps are not be able to provide as much heat as your current boiler can provide.

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 120 degrees. (One air-to-water heat pump – Artic’s high temp cascading design – is able to achieve temps of 180 degrees but it uses refrigerants that will not be permitted in the U.S. after Jan. 1, 2025.)  

Converting your current hydronic distribution system to a low-temperature – 80 to 120 degrees – 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).

I have radiant flooring/I am considering adding radiant flooring. Can I use a heat pump for that?

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).

What if I want to keep my current heating system for back up?

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.

I have an old house with many small rooms. What size heads would be appropriate?

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.

What is the expected average lifespan of a heat pump?

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

Are ground source heat pumps better than air-source heat pumps?

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).

What do I need to consider in the placement of the outdoor unit?

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.

I live in a condominium association. What are the options for siting the condenser?

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.

How many amps do heat pumps need?

Generally, you need a 200-amp service to support heat pumps.

Will my heat pump function in a power outage?

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.

Do certain companies offer a smartphone app to control the heat pump remotely?

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.

What maintenance is required for heat pumps and how can mold be prevented?

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).


Is my heat pump eligible for a federal tax credit?

Yes! A federal tax credit of $2,000 is available for installations of heat pumps made on or after January 1, 2023. You can claim an additional $600 for upgrading your electric panel. Find more details at Home Energy Tax Credits | Internal Revenue Service (irs.gov).

Is my heat pump eligible for a federally-funded rebate?

Federal rebates for heat pumps are not yet in effect.  As soon as we have more details, we will update this page. For more general information about the federal rebates, go to How much money can you get with the Inflation Reduction Act? — Rewiring America. You can sign up to receive updates about Massachusetts roll-out of the IRA rebate program at: Sign up (e2ma.net)

Are there state-sponsored financial incentives for homeowners who install heat pumps?

In Massachusetts, the whole home heat pump incentive is $10,000 per home. The partial home rebate is based on heating capacity installed and is $1,250 per ton of heating capacity. A ton of heating capacity equals 12,000 BTUs, roughly enough to heat a room 20 ft x 30 ft, or about 600 square feet.  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. Rebates are sent to the consumer after they pay the contractor and submit receipt and other application paperwork to Mass Save.

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:https://cleanheatri.com/.

What is the process for applying for a whole- or partial-home rebate for the installation of heat pumps?

Massachusetts homeowners must fill out the rebate form, found here:  >Mass-Save-Air-Source-Heat-Pump-Rebate-Form.pdf (masssave.com).

Rhode Island’s rebate forms can be found here:  Heat Pump Incentives | Rhode Island Energy (rienergy.com).

If your electricity is provided by a municipal power company, check with your town about its rebates.

For Mass Save's Whole Home rebate, what evidence is needed that the heat pump system will serve the whole house?

Homeowners and installers must fill out and sign Mass Save's Whole-home heat pump verification form, found here:  Mass-Save-Whole-Home-Heat-Pump-Verification-Form.pdf (masssave.com).

Do I need to use an approved installer in order to qualify for rebates?

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: Rhode Island Heating and Cooling Program Participating Contractor List (rienergy.com).

How do I find out what state rebate applies to my heating upgrade project?

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.

Can I apply for any no-interest or low-interest loans to finance my heat pump installation?

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. Go to Heat Pump Incentives | Rhode Island Energy (rienergy.com) for more information.

For Massachusetts residents, Mass Save offers zero-interest financing opportunities for energy-efficient home upgrades, including up to $50,000 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).

What is the maximum number of units in a condo association eligible for the Mass Save whole home rebate?

In a condo association with four or fewer units, each unit may qualify for the whole home rebate.  Condos in larger buildings would need to apply to the multi-family program, which has a different incentive structure. See Mass Save | Multi-Family.

Are there incentives for the purchase of heat pump water heaters?

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.  For more information on incentives for heat pump water heaters and other appliances and equipment, go to Rebate Programs | Rhode Island Energy (rienergy.com).  The rebate form can be found here:  rie-2680081-rebate-form-hpwh.pdf (rienergy.com).

The Inflation Reduction Act also incentivizes heat pump water heaters. The $2,000 tax credit for heat pump water heaters came into effect on January 1, 2023, and will last 10 years. There will be federally funded rebates for heat pump water heaters too, but we don’t yet have the details. We’ll update this site when more information becomes available.

I purchased my energy-efficient appliance/equipment before January 1, 2023, but it was not delivered until after that date. Does it still qualify for a rebate?

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

What’s the process of applying for state rebates for energy-efficient upgrades and appliances generally?

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.

You can download the forms from Mass Save website, Residential Rebates & Incentives for Homeowners, Renters, & Landlords (masssave.com)

If you get your electricity from a municipal electric company, contact your utility for the appropriate forms.  

Rhode Island’s rebate program page is here:  Rebate Programs | Rhode Island Energy (rienergy.com).

My boiler supplies my domestic hot water (for showers, dishwasher, etc.).  To qualify for a Whole Home Heat Pump Incentive, do I have to buy new domestic hot water equipment?

No, you can continue to use your pre-existing heating system for hot water.  However, the space heating must be disabled if the heating system is retained for domestic hot water.  For Massachusetts residents, this information is contained in the Whole-home Heat Pump Verification Form, Mass-Save-Whole-Home-Heat-Pump-Verification-Form.pdf (masssave.com).  Rhode Island residents can go to Homeowner - Clean Heat Rhode Island (cleanheatri.com) to schedule a virtual consultation and learn more.

After you have installed a heat pump

What maintenance is required for heat pumps and how can I prevent mold forming inside the indoor units?

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).

Does it ever make sense to turn down my heat (or cooling), such as overnight or when no one is home?

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. 

For more information and tips on maximizing the benefits of your air source heat pump, go to Getting the Most From Your New System - Massachusetts Clean Energy Center (masscec.com). 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.

I live in Eversource territory. How do I apply for the discounted electric heat rate?

If you get your electric bill from Eversource in eastern Mass, you may request a change to a slightly discounted electric heating rate. Eversource currently has four residential rate classes:

  • R1 - Residential 
  • R2 - Residential Assistance 
  • R3 - Residential Space Heating  
  • R4 - Residential Space Heating Assistance

The MA Department of Public Utilities (DPU) sets the rates that Eversource can charge their customers, and this changes twice a year for winter rates (January - June) and summer rates (July - December). The current Eversource Delivery charges – the lower half of your bill – are nominally lower for customers using electricity as their primary heating source. You can contact Eversource by phone or through your online account to change your rate class to reflect electric space heating; although you will only save fractions of a cent per kWh, in the future the DPU may authorize further discounts for those with electric space heating. Plus, changing to the electric heating rate class may be helpful for local or statewide data collection/analysis — to identify customers who have converted to heat pumps and those who still need to electrify.

At present, no other utility in the state offers this reduced rate. This discounted rate is not available to households that still have fossil fuel heating for part of their home.

Heat Pump Water Heaters

How does a heat pump water heater work?

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.

Is a HPWH more efficient than other types of water heaters, such as gas-fired and electric resistance water heaters?

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.

Is a HPWH more expensive than other types of water heaters, such as gas-fired and electric resistance water heaters?

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

How can I find the latest information on incentives to help with the cost of installing a HPWH?

MassSave offers a $750 rebate for installing a HPWH, Heat Pump Water Heater Rebates I Residential I Mass Save.   

Similarly, Clean Heat Rhode Island also offers a $750 rebate, Incentives - Clean Heat Rhode Island (cleanheatri.com) 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, Rebate Programs | Rhode Island Energy (rienergy.com).

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.  Therefore, if you are thinking about getting both heat pumps and a HPWH, you may want to consider installing them in two separate calendar years.


How do the operating costs of a HPWH compare to other options?

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.

If I get a HPWH, will I need to install a 240-volt line to serve it?

Not necessarily.  120 volt HPWHs are being manufactured and used around the country.  However, in cold climates, such as the Northeast, it is not clear whether 120-volt HPWHs are the best choice. 

If I get a HPWH, will I need to upgrade my electric system?

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.  Also, there are incentives to do so.  For example, 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.   See 25C Electrical Panel Tax Credits: A Guide for Homeowners (rewiringamerica.org)  Clean Heat Rhode Island offers a $500 rebate to upgrade electrical service, 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: Energy Saver Home Loan Program (masshousing.com).

I’ve heard that a HPWH cannot be installed in a small utility closet. What kind of space is needed for a HPWH?

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.

I have a finished basement heated with air source heat pumps. Will installation of a HPWH lower the temperature of the basement and cause the heat pumps to run less efficiently?

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.

Where can I learn more about heat pump water heaters?

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).