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Heat & Cool: Heat Pumps

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Home Energy

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What is a Heat Pump?

Heat pumps are amazing electrical HVAC (Heating Ventilation Air Conditioning) devices that both warm and cool your home and function like a combined furnace and central air conditioner while also reducing your household’s overall carbon footprint!  Heat pumps are exceptionally energy-efficient and environmentally friendly compared with other home heating and cooling systems, because they absorb and move heat from the air (or the ground) and don’t have to create the heat (e.g., no burning oil or gas or using resistive electrical heating). This makes them significantly more energy-efficient than traditional furnaces or boilers. They can be used to heat and cool part or all of your home and you can also get separate units to provide your house’s hot water.

 

How Do They Work?

Heat pumps are similar to refrigerators and air conditioners because they use a refrigeration cycle involving a chemical refrigerant to absorb and release heat energy and are designed to both cool and heat.

  • Heating: In winter, the outdoor unit extracts heat from the outside air or ground (even in sub freezing temperatures!). The refrigerant absorbs this energy, is pressurized by a compressor to increase its temperature, and then releases that heat into your home via an indoor unit.
  • Cooling: In summer, the system acts like an air conditioner. It reverses the flow of refrigerant using a reversing valve, pulling heat from inside your home and dumping it outdoors to cool your space. In cooling mode, like for air conditioners, heat pumps will also act to dehumidify the air.

There are two main types of heat pumps when it comes to how the outdoor energy exchange happens:

  • Air-Source Heat Pumps (ASHPs) that transfer heat between the indoor air and the outside air. These are very common and easy to install. Mini-splits systems are one example.
  • Geothermal (Ground-Source) Heat Pumps that transfer heat between a building and the ground. These systems involve drilling a well and/or burying piping in the ground and so are more complicated to install and less common, but they are the most efficient type of heat pump system.

 

Why Use Heat Pumps? 

One of the most effective ways to reduce a household’s overall carbon footprint is to electrify the home’s heating — and cooling — with a heat pump system. Anyone who lives or has a business (or other concern) in Acton can contact a volunteer Acton Clean Energy Coach (using this Coaching Request Form) and they will help you understand heat pump technology for heating and cooling (and for hot water heating), available rebates, and answer any other questions you might have. Every house is unique. So when you are ready, a coach can also look at the specifics of your house in order to consider what type of system might work best for you.

To see a short video from a homeowner in Acton who has installed two types of heat pumps and gone fossil fuel free, click on this link Virtual Carbon Free House Tour.

 

When To Make The Change

Ideal times to install a heat pump include:
• when you need to replace your existing heating or cooling system;
• when you want to add air conditioning (because heat pumps provide cooling as well as heating); and
• when you are installing on-site solar (because it can offset the heat pump’s electrical use).
The exciting news is that heat pump technology has advanced rapidly, and there are plenty of options to meet your comfort needs efficiently in both summer and winter. Planning ahead is important!

 

Impact

Average household carbon emissions will be reduced by approximately 2–3 tons annually with full conversion to a heat pump system from an existing fossil fuel system — depending on the size of the home and the nature of the existing heating system, as explained in the Deep Dive tab.

 

Financial And Other Benefits

If you’re switching from an oil heat system, or adding central air conditioning to your home, you might see immediate financial savings by switching to a heat pump system. If you currently burn natural gas, it’s possible that the switch to a heat pump system might result in a small increase in cost to operate, given current, relatively low “natural” gas prices — unless you generate on-site solar electricity, which will reduce what’s needed from the grid. (That said, gas prices are expected to rise in the longer term.) Nevertheless, you may find that a heat pump system is an affordable way to cut carbon emissions substantially right away. As gas prices rise, heat pumps are expected to become cheaper alternatives to natural gas. Other important climate and health benefits of electric heat pump systems include reductions in:

  • the routine release of methane (and other products of combustion) inside your home,
  • the risk of dangerous gas leaks, and
  • carbon and methane emissions being released into the atmosphere.

(See the separate Switch to Induction Cooking Action for information on eliminating gas from your kitchen.)

 

Make A Plan

A more-gradual way to get started with heat pumps and reduce the fossil fuel you burn is to make the switch for only one or two rooms in your home. You can do this by having a “mini-split” heat pump system installed that covers those rooms, while the existing system heats the rest of the home. A great “target” for this strategy is any room(s) or area(s) that tend to be uncomfortably cool or warm, depending on season.

Start by developing a “Heat Pump Plan” before your existing heating system needs to be replaced. An Acton Clean Energy Coach can help you create a plan and all consultations are free. See our action, “Create a Zero Emissions Plan,” for suggested checklists and formats to help with planning. Because choosing an installer and equipment can be a time consuming and confusing process, waiting until you are out of heat in the winter to start researching heat pump options can potentially result in choices that are not fully informed.  By developing a plan in advance, you will have time to consult with your current HVAC dealer or to find a new heat pump installer.

 

Incentives

There are several incentive programs for heat pumps to sweeten the deal.  State incentives, and point-of-sale rebates, can be significant for homeowners! Some programs can mix and match for additional savings. Massachusetts has some of the best renewable energy promotions in the country including rebate structures that aim to support lower income households, non-profit organizations, and municipalities. Below please see the information related to heat pump incentives as of January 2026, but check to see if they have changed since.

 

MASSACHUSETTS PROGRAMS

Mass Save Programs This site includes everything related to heat pumps and energy efficiency, but you must be a traditional utility customer; that is, municipal electricity customers–Concord, Littleton, etc.–do not qualify.

Mass Save HEAT Loan 0% financing for 5-7 years. –  Up to $25,000

Air Source Heat Pumps (ASHPs) rebates for Mass Energize qualified products

  • Whole home conversion – $2,650  per ton. Up to $8,500 total
  • Partial home conversion – $1,125 per ton. Up to $8,500  total
  • Basic – $250 per ton. Up to $2500 total
  • Income based enhanced incentives – up to $16,000 or up to no cost through Turnkey Services.

Air to Water Heat Pumps rebates for Mass Energize qualified products

  • Whole home conversion – $2,650 per ton. Up to $8,500
  • Income-based enhanced amount – up to $16,000

Ground Source Heat Pumps (GSHPs) rebates for ENERGY STAR certified products.

  • Whole home conversion – $13,500 per home
  • Partial home conversion – $2000 per ton. Up to $13,500 total
  • Income-based enhanced amount (whole or partial-home) – up to $25,000

Heat Pump Water Heaters rebates for certain ENERGY STAR certified products.

  • $750 per unit
  • $1500 for a split system heat pump water heater (i.e., where the condenser is outside of house)
For eligibility, most of these incentives REQUIRE A HOME ENERGY AUDIT from MassSave!

Plus, you should do everything you can to add the maximum insulation and reduce drafts significantly. To get started with this, sign up for a no-cost Home Energy Assessment and also go to the Insulate and Weatherize to the Max Action).

 

FEDERAL PROGRAMS

There are no longer any federal tax credits for residential clean energy investments. While originally extended through 2034 by the 2022 Inflation Reduction Act, the “One Big Beautiful Bill” enacted in July 2025 rolled back its expiration date to the end of 2025.

For more information, see the Steps to Take and Deep Dive tabs.

Steps to Take

  1. Assemble basic information about your existing heating system, especially the date when it was installed and a record of service indicating any emission tests or efficiency measurements. Also, review the quantity of oil or natural gas you have used each year, or the costs you have paid; this will help determine the size your heat pump system needs to be. Your energy use data will also be a useful input into a Home Energy Assessment or a plan to Insulate and Weatherize your home so as to reduce your heating requirements as much as you can before seeking a quote on a heat pump system. This will allow you to buy a smaller, less-expensive system (see Step 4).
  2. Schedule an appointment with a professional to get advice.  You can sign up for free consultation from an Acton Clean Energy Coach with this Coaching Request Form (specify you need help with heat pumps). To find out more about the coaches see “The Clean Energy Coaching Program” on the Town of Acton Sustainability Office website. You can also use Mass Save to get Home Performance Contractor (HPC) through their Home Energy Assessment program but be sure to select one with experience in heat pumps and related technologies. FYI, as of March 2026, the Town of Acton’s Sustainability Office was in the process of trying to select and contract with a single HPC who would be dedicated to serve Acton, so check with them to see if that has happened yet.
  3. Look for heat pump contractors/installers with plenty of heat pump experience. The Clean Energy Coaches or HPCs will share names of contractors that may have experience most relevant to your type of home and situation. Schedule visits to your home to get to know potential contractors, and ask them for local references. Ask for suggestions for size, configuration, and types of equipment, and request initial pricing, but make it clear that before you make any decisions you will be considering all the elements that could affect your heat pump purchase (see the next step). A Clean Energy Coach can suggest key questions to ask any HVAC contractor. Make sure that the heat pump installer you ultimately hire is eligible to access all the heat pump incentives from MassSave and other sources.
  4. Get information about other energy measures that could affect your heat pump decision, starting with any remaining opportunities to reduce your “heat loss” with insulation and weatherization (thereby reducing the size of the heat pump you would need, and thus, the cost).  Ensuring that you’re reducing heat loss could also involve getting a Home Energy Assessment from Mass Save and/or contacting a MassSave HPC, as described in the Insulate & Weatherize to the Max Action. And/or it might also involve contacting a solar installer or looking into making your next car an EV and charging it at home. To install a whole-house heat pump system, you may need to upgrade your electrical service and panel, so you might as well design the new electrical supply to accommodate EV charging and/or a solar array.
  5. Compare and choose between different types and configurations of heat pump system. If you have not yet consulted with a Clean Energy Coach, their feedback could be very helpful comparing these options! Determine whether a ground source heat pump is feasible in your location and for your budget. If so, this will be the most efficient type of heat pump with the lowest electricity use. The high initial price for installation may be an obstacle unless you take out a loan for it ( 0% HEAT Loans are available). Alternately, air source heat pumps are much less expensive to install, and offer the choice of installing one central air source heat pump to replace your existing furnace and use your existing air ducts, or configuring one or more “mini-split” heat pump units to serve one or two rooms each. Configuration options are discussed further under the Deep Dive tab.
  6. Get Quotes. Once you have identified what heat pump configuration will work best for you, get price quotes for a range of heat pump capabilities. For example, make sure you are looking at “cold climate” heat pumps that will work well in Acton’s cold winter weather. Look for the highest Heating Season Performance Factor HSPF) ratings, as well as a high SEER (Seasonal Energy Efficiency Ratio) rating; ask for model numbers so you can research independent information on the equipment. Ask your contractors to show you the NEEP (Northeast Energy Efficiency Partnerships) ratings of each heat pump model you consider. See additional information under the Deep Dive tab. One more thing, if you are planning to retire your oil tank (first of all – congratulations!), but also try to include that in the work quote.
  7. Evaluate your bids with a Clean Energy Coach! Once you have some options priced out, talk them over with independent sources of advice. This is probably the most important time to speak with a coach. He or she can help you spot any question areas that need follow-up before signing a contract. The Coach’s job is to help you find the best option for your home. If you used an HPC Energy Specialist for your Home Energy Assessment, they should be able to suggest heat pump experts. If your HPC provided both the assessment and the heat pump quotes, then get competing quotes from other installers and ask questions of their competitors. Note Acton’s Clean Energy Coaches are available to help you all the way to the end of your installation and project.
  8. Get Your System Installed – and work with your contractor to get your Mass Save rebate paperwork submitted.
  9. Congratulations on heating and cooling with your new heat pump system! Are you all finished consulting with your coach? Not necessarily. Getting used to new technology can sometimes be a challenge. A Clean Energy Coach can help you post-installation, by suggesting optimal settings and other tricks of the trade.
  10. Once you’ve transitioned to a heat pump system for your home, please write a Testimonial for this site with your story: what worked, what was difficult, how well contractors met your needs, and how comfortable and affordable your heat pump system has been. Thanks!

Deep Dive

What Are Heat Pumps?

Traditional heating systems burn fuel to create heat; heat pumps work by “pumping” heat into or out of a building or home. Though they require electricity to operate, heat pumps use only 20–50% of the electricity that would be used by traditional electric resistance heaters. A heat pump can supplement your existing heating system or completely replace it. Changing to heat pumps provides the greatest economic benefit if your home is currently heated with oil, propane, or electric baseboards, but many will find it affordable to replace gas heat now or in the near future. Here are some more-detailed resources on heat pumps:

• Energy Sage
• Massachusetts Clean Energy Center (MassCEC)

 

How Important Are Heat Pumps For Meeting Acton’s Net Zero Carbon Goal?

For most Acton residences, the single most impactful Action to cut carbon emissions is to stop burning oil, gas, or propane for heat, and switch to an electric heat pump system. As the table below shows, this can cut an average of 3.2 metric tons of carbon dioxide equivalents (MTCO2e) every year. The reduction will be a little greater for homes previously heated with oil, and a bit less for those using gas.

Heat pumps are even more impactful when the electricity to power them is 100% renewably sourced — in Acton a renewable supply is readily available through Acton Power Choice GREEN. The additional emissions reduction realized by using 100% renewable, zero-emission electricity for your heat pump system will average about 2 tons annually.

The Top 6 Actions for Cutting Household Carbon Emissions:
Average Reduction in Tons of CO2e per Action per year

Switch to Heating & Cooling with Heat Pump(s) 3.2 tons
Opt up to APC GREEN for heat pump use 2.0 tons
Opt up to APC GREEN for charging use by 1 EV 1.5 tons
Opt up to APC GREEN (at average household use) 1.5 tons
Insulate & Weatherize to the Max 1.5 tons
Drive Electric (1 car) 2.6 tons
Install On-site Solar 2.5 tons
Eat More Plant-Based Meals 0.6 tons

Sources: MassEnergize Carbon Calculator Methodology, Energize Acton conversions to metric tons based on 2,204.62 pounds/metric ton.

Reductions will vary from one household to the next, but if a household’s members can do all the things in this table (there are 6 Actions listed; all the APC Green actions are counted as one), they would eliminate approximately 13 tons of carbon from their emissions each year. This is eliminating roughly 74% of the average 17.5 tons of emissions per household counted in the 2019 Acton Greenhouse Gas Inventory from home energy use and passenger cars in Acton. (Note: on-site solar was omitted from the 13 ton total because most of solar’s potential emissions reduction is achieved in this scenario by APC GREEN.)

 

What Is The Basis For The Estimate of 3.2 Tons/Year Emission Reduction?

This estimate of emissions reduction is intended as an approximation of typical, average, or potential results in order to convey relative magnitudes of various Actions; this is not a prediction of actual results of individual heat pump installations. Using MassEnergize Carbon Calculator Methodology, MassEnergize estimated a 7,199 pounds/year reduction by assuming that an oil furnace is partially displaced by a high-efficiency, central ducted air-source heat pump, with energy savings from the Technical Reference Manual used for evaluation of MassSave programs. For this partial displacement scenario, it appears that this MassSave analysis had assumed HSPF (Heating Seasonal Performance Factor) values for heat pumps from 8.2–9.6, which are relatively inefficient (i.e., lower than the HSPFsfor ductless mini-split heat pumps [ductless mini-split heat pumps/DMSHP] which can be up to 12).

Source: Energy Optimization Study, October 9, 2018, Table 3, page 7. More generally, it may be possible to achieve better emission reductions if existing oil burners are removed, even if electric resistance heat is used for backup during very cold hours/days.

 

What Incentives Are Available For Heat Pumps?

All homes qualify for heat pump incentives from Mass Save. Some homes may qualify for additional incentives from Massachusetts state agencies. There are typically higher incentives for low- and moderate-income customers. The incentives as of 2026 are shown in the introduction section but make sure to check for the most-current information on incentives because they may change.

 

What Is The Difference Between “Air Source” and “Ground Source” Heat Pumps?

There are two basic types of heat pumps:

  • Air-Source Heat Pumps (ASHPs) exchange heat with the air outside your home. Some ASHPs are efficient down to sub-zero outdoor temperatures. ASHPs for homes that already have ducting are called central heat pumps, while so-called ductless “mini-splits” are suited for homes that don’t have existing ducting. All ASHPs provide energy-efficient heating and cooling for your home. ASHPs use 30–50 percent as much electricity as traditional electric resistance heaters, such as electric baseboards. Download the NEEP Air-Source Heat Pump Buyers Guide for more information.
  • Ground-Source Heat Pumps (GSHPs) can provide highly efficient heating, cooling, and water heating by utilizing the nearly constant temperature underground to heat or cool your home. GSHPs are typically the most efficient type of heat pump, but installation is more complex and the initial cost is somewhat higher than for ASHPs. See more about GSHPs here.
 What Are The Different Configurations For Heat Pump Systems?

There are three main options. Experienced heat pump professionals can help you compare the pros and cons of these configurations.

  1. Install one central heat pump (air-source or ground-source) to take the place of your existing furnace and use your existing air ducts.
  2. Configure a heat pump system with one or more “mini-split” heat pump units to serve one or two rooms each.
  3. Retain your existing furnace or boiler (if it’s not too old) and start by installing one mini-split to supply one or two rooms that are used frequently. This will provide you some experience with heat pumps, and may help when you eventually complete your heat pump system by removing your fossil fuel heating equipment — at which time you can install a central heat pump and/or multiple mini-splits, as appropriate.

Once you have an idea what general heat pump configuration you think will work best for you, dig into the following details before getting price bids:

  • Be sure you are looking at “cold climate” heat pumps that will work well in Acton’s cold winter weather. Look for the highest The heating Seasonal Performance Factor (HSPF) ratings, as well as  a high Seasonal Energy Efficiency Ratio (SEER) rating, and ask for model numbers so you research them and get independent information.
  • If you are retaining a fossil fuel heating system (at least temporarily as a backup), make sure you get careful estimates of how much fuel will be used, and ask for a set of smart or “integrated” controls that will manage the multiple heat pump(s) and other systems (to prevent potential inefficiencies).
  • If you are not retaining your old system, ask if your new heat pump(s) will include internal electric resistance heating for the coldest hours of the winter, or whether the heat pump(s) will operate at our coldest temperatures (e.g., 0°F or below).
  • Make sure any price quotes specify that the outside compressor unit(s) will be located appropriately for air flow, elevated to protect them from snow, and kept out of the way of any dripping water or ice.

Last Updated 3/14/26

Testimonials

We had a whole-house air-source heat pump installed during construction of our new Acton house in 2019 (pictured here), based on our 6 years of…
Heat pumps are amazing
Submitted by: Fran Cummings
I added a whole house heat-pump to get off gas and to add air-conditioning and was pleasantly surprised how much quieter it was without the…
Pleasantly Surprised
Submitted by: Paul Reisberg

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