Learn About Air-Source Heat Pumps

Heat pumps can provide cost-effective and energy-efficient heating, cooling and water heating for homes and businesses. While traditional heating systems burn fuel to create heat, a heat pump instead works by moving heat into or out of a building. Though they require electricity to operate, efficient heat pumps can provide the same amount of heating for a third of the electricity needed to power traditional electric heating.

Heat pumps circulate a liquid, called a refrigerant, between an indoor unit and an outdoor unit. When heating a building, the heat pump heats the liquid by pressurizing it, pumps it from outdoors inside, and then circulates it through the home or building's heating system. After the liquid transfers the heat into the building, it is depressurized and cooled. The liquid then travels to the outdoor unit, where the ambient temperature warms the refrigerant, and the process begins again.

Heat pumps can also be used to cool buildings through a similar process. In this case, the warm air inside a home or building is cooled by the liquid, which has been depressurized. The refrigerant is then sent outside and pressurized, which heats it up, and the ambient outdoor temperature cools it. 

Advances in technology over the past few years have made air-source heat pumps an efficient source of heating in cold climates like Massachusetts. Models on the market today can operate efficiently even when it is below zero degrees Fahrenheit.

Much like air conditioners, air-source heat pumps can be installed either as central units or split units. Central units utilize a building’s heat distribution system to heat and cool a building and can also be used for water heating. Ductless air source heat pumps can provide heating and air conditioning without the need for central ductwork. Each ductless system includes one outdoor unit connected to one (single-zone) or more (multi-zone) indoor wall, floor or ceiling air distribution units. Ductless ASHPs are often referred to as ductless mini-splits. 

VRF units are customized systems that are typically larger, provide greater control and efficiency, and support a commercial-scale building’s entire heating and cooling demands.

Air-to-water heat pumps transfer heat to or from a hydronic distribution system such as radiant floors, radiators, fain-coil units, or baseboard water circulation systems.Air-to-water heat pumps have been selected to receive the 2019 ENERGY STAR Emerging Technology Award

Economics & Incentives 

Efficient heat pumps can reduce heating costs when replacing or supplementing an oil, propane, or electric resistance heating system. In fact, air-source heat pumps can heat your home or building for half to one third the price of traditional electric heating. 

MassCEC currently provides grants to support VRF projects and whole-home air-source heat pump projects. Please see our ResidentialBusiness, and Government/Non-Profit Clean Heating and Cooling websites for more details on how to apply for funding.

A summary of incentives is outlined below:


Incentive Amount
Mass Save 0 Percent Interest HEAT Loan  0% for 7 years; up to $25,000
MassCEC Whole-Home Air-Source Heat Pump Rebate $2,500 standard rebate per residence; up to $5,000 income-based rebate per residence
Mass Save Heat Pump Rebate $1600 per ton for projects replacing oil, propane, or electric resistance
Alternate Energy Credits Varies



Commercial includes projects owned by both businesses and government/non-profit entities. 

Incentive Program Amount
Mass Save Custom Measures Varies
Mass Save Upstream $50-$125/ton
Alternate Energy Credits Varies
MassCEC VRF Grant $600-$1,000/ton, up to $150,000

Next Steps for Installing an Air-Source Heat Pump 

Visit our Residential, Business, and Government/Non-Profit Clean Heating and Cooling for more information on finding an installer and starting the process of getting a system installed. 


Best Practices for Installing and Operating Air-Source Heat Pumps

Northeast Energy Efficiency Partnership offers resources for installers and consumer on sizing, selecting, installer, and operating air-source heat pumps in a climate like Massachusetts'.

MassCEC and MassSave collaborated to produce the following tips for operating your air-source heat pump: