Customer Service: (802) 865-7300   Monday-Friday 8am-5pm

Air-Source Heat Pumps

Or Cold Climate Heat Pumps

Air-source heat pumps (ASHPs) are a type of heat pump that exchange heat between a building and the outside air by circulating refrigerant between indoor and outdoor components, similar to a central air conditioner’s outdoor condenser and indoor evaporator.

Unlike a central air conditioner, ASHPs can reverse their refrigeration cycles to provide heating, too. In recent years, “cold-climate” ASHP technology has advanced so that many models can provide space heating without fossil fuel backup at very low outdoor temperatures. Sometimes ASHPs are referred to as cold-climate heat pumps, or "CCHPs."

Rebates for qualifying cold-climate ductless mini-split, centrally-ducted, and air-to-water ASHPs are available for all BED customers. If you have questions about ASHPs and our available rebates, please call us at (802) 865-7300.

Receive up to $3,350 toward the purchase of an eligible cold climate heat pump (CCHP).

Download the Rebate Form (PDF)

Learn more about other amazing rebate offers that are part of our Green Stimulus program.

Preferred Heat Pump Installer Network

Burlington Electric Department recognizes these important partners – all members of Vermont’s Efficiency Excellence Network – for their work and ability to deliver the highest-quality heat pump services to our customers.

If you would like your company to be included on our list of preferred heat pump installers, please contact Jennifer Green at (802) 865-7349 or

171 Leroy Rd
Williston, VT 05495
(802) 655-9191
34 Commerce Avenue
South Burlington, VT 05403
(802) 864-7156
1570 South Brownell Road
Williston, VT 05495
(802) 448-8552
416 Roosevelt Hwy
Colchester, VT 05446
(802) 655-1489
73 Prim Road
Colchester, VT 05446
(802) 860-4090
339 Red Rock Road
Colchester, VT 05446
(802) 893-9992
Swanton, VT 05478
(802) 782-5376
188 Krupp Drive
Williston, VT 05495
(802) 658-6055



  • ASHPs can provide an easy-to-install heating and cooling solution for buildings without ductwork and can provide a spot comfort solution for rooms that were not previously conditioned.
  • ASHPs can be more affordable than other heat pump system types, so can serve as a more accessible way for some building owners to strategically electrify and reduce their carbon footprint.
  • For cooling, an ASHP may cost 40% less to operate than room air conditioners of equivalent capacity.
  • For very well-insulated and air-sealed buildings, ASHPs do not require a fossil fuel backup for operation in extremely cold outdoor temperatures.
  • ASHP equipment can last 12 – 15 years, depending on the installation location and exposure of the outdoor unit. Refer to manufacturer’s manuals for specific preventative maintenance tasks for equipment.

NOTE: If you heat your building with natural gas - as most Burlingtonians do - you might not save money with an air-source heat pump; your electric bill could go up by more than your gas bill goes down. If you are considering an air-source heat pump, consider a ground-source heat pump instead, and also think about weatherizing first. 

Contact the BED Energy Services team (802) 865-7300 or e-mail us to get started with free, unbiased advice. We’ll walk you through the decision-making process and help you maximize your energy investments. 

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Ductless “Mini-Split” Systems

Split SystemDuctless, mini-split heat pumps are a common type of ASHP serving Burlington homes and businesses.

How They Work

Mini split heat pump systems pump refrigerant between an outdoor unit and an indoor unit (or multiple indoor units). As the name implies, these systems do not include ductwork for distribution; indoor units recirculate room air using the onboard fan.

Indoor units are sometimes called evaporator units and outdoor units are sometimes called condenser units, but since heat pumps can reverse their refrigeration cycle to operate in either heating and cooling mode, it is more accurate to keep it simple and call them ‘indoor’ and ‘outdoor’ units.

In cooling mode, the indoor unit serves as the evaporator and the fan blows air over cold coils to remove heat from indoor air using refrigerant. The outdoor unit serves as the condenser, and hot coils reject heat from the indoor spaces via the refrigerant loop into the outside air.

In heating mode, the heat pump flips its operation, and the indoor unit serves as the condenser and the fan blows air over hot coils to add heat to indoor air using refrigerant. The outdoor unit serves as the evaporator, and cold coils reject heat from the indoor spaces via the refrigerant loop into the outside air.

A fossil fuel source is usually maintained as a backup heat source to avoid heat pump operation during extremely cold outdoor conditions, when the equipment relies on electric resistance elements instead of the refrigerant loop to provide heat to indoor spaces.


Efficiency Vermont Heat Pumps Learn More
"8 Ways NOT to Use a Heat Pump" from Efficiency Vermont

  • How well an ASHP heats and cools your home depends on the number of inside wall units, the floor plan, and the insulation and air-sealing quality of the building. Field studies show that ASHPs work best in weatherized buildings. In some buildings it is more cost-effective to weatherize along with the ASHP installation or weatherize first and install heat pumps later.
  • Typically, ASHPs cannot serve as a full replacement of an existing heating system as they don’t condition every room in a building and may be unable to provide enough heat during extremely cold outdoor temperatures.
  • A single outdoor unit can serve up to four indoor units, and a single indoor unit can condition multiple rooms; these are called ‘multi-zone’ or ‘multi-head’ installations.
  • A building may be served by multiple outdoor and indoor units depending on the number and size of the spaces needing conditioning.
  • Consider locating indoor units less than 50 feet away from outdoor units to improve comfort and energy performance.
  • Variable refrigerant flow (VRF) designs offer enhanced comfort and energy savings by pumping refrigerant to match demand for both heating and cooling simultaneously from a group of indoor units which can result in increased energy savings.
    • BED can offer custom rebates for VRF systems serving commercial buildings. Call us at 865-7440 or write us to discuss potential energy savings and financial rebates.
  • Indoor units are usually hung on walls but can also be suspended from ceilings and mounted flush with drop ceilings.
  • Outdoor units are usually installed on curbs 4 to 8 inches above the ground, but can also be installed on flat roofs.
    • Avoid placing units near gutters as water may drip on unit in winter and freeze, restricting air flow through the unit and reducing its efficiency.
  • Refrigerant piping must be routed through walls and ceilings between outdoor and indoor units and should be insulated per Vermont’s residential and commercial building energy standards, as applicable.

Centrally-Ducted Air-Source Heat Pumps

Ducted ASHP systems use existing ductwork in a building to distribute conditioned air for both heating and cooling.

Heat pumps can be retrofit to work with your existing furnace. Customers considering these ASHP systems should work with HVAC contractors with controls systems experience to program a centrally ducted ASHP system for effective and energy-efficient operation.

Rebate: BED has increased the centrally ducted heat pump incentives to a maximum total today of up to $8,750 to support local projects through December 31, 2021. 

REBATE: Centrally Ducted Air-Source Heat Pump

Air-to-Water Heat Pumps

Air-to-water heat pumps integrate with hydronic distribution systems to circulate water for heating and cooling, and can provide domestic hot water. Hydronic distribution uses water as a heat transfer fluid to distribute heat.

Heat pumps can be retrofit to work with your existing boiler. Customers considering these ASHP systems should work with HVAC contractors with controls systems experience to program an air-to-water ASHP system for effective and energy-efficient operation.

Rebate: BED has increased the air to water heat pump incentives from a maximum total today of $5,000 to $12,500 to support local projects.

REBATE: Air-to-Water Heat Pumps