Heat pumps work much the way your refrigerator does, by circulating a substance called a refrigerant through a cycle of evaporation and condensation. During the heating season, a heat pump moves heat from the outside air to your home. (Since the air outside always contains some heat, a heat pump can supply heat even on cold winter days.) During the summer, a heat pump cools just like an air conditioner, by transferring heat from inside to the outdoors.

Air source heat pumps have two parts: an outdoor condensing unit and one or more indoor air handling units, connected by a conduit through the wall. Some are ductless and some use ducts. Want to see it in animation? Watch the mini-split videos on Mass Save here: https://www.masssave.com/en/shop/equipment/electric-heating-and-cooling-systems.

I heard heat pumps don’t work in New England.

This used to be true, but now effective cold climate heat pumps are available and they work very well in New England. 

Doesn’t it cost more to heat with electricity?

No, because heat pumps move heat rather than generate it, they can heat and cool at a significantly lower cost than other systems. In fact, the Northeast Energy Efficiency Partnerships found that in the Northeast and Mid-Atlantic regions air source heat pumps save around 3,000 kWh (or $459) when compared to electric resistance heaters, and 6,200 kWh (or $948) when compared to oil systems. When displacing oil (i.e., the oil system remains, but operates less frequently), the average annual savings are near 3,000 kWh (or about $300).

Do I have to replace my entire existing heating system to use heat pumps? 

Heat pumps work with most heating systems, such as forced hot air, radiators, or radiant (floor) heat. They can also be “ductless,” in which case they transfer warm or cool air directly into the house. Some people choose to install heat pumps on top of their legacy heating system, so that the old system can kick in if temperatures get very cold. 

Types of Air-Source Heat Pumps

The different types of air source heat pumps are described below.

Ductless vs. Ducted vs. Short-Run Ducted

Ductless applications require minimal construction as only a three-inch hole through the wall is required to connect the outdoor condenser and the indoor heads. Ductless systems are often installed in additions.

Ducted systems simply use ductwork. If your home already has a ventilation system or the home will be a new construction, you might consider this system.

Short-run ducted is traditional large ductwork that only runs through a small section of the house.  Short-run ducted is often complemented by other ductless units for the remainder of the house.

Split vs. Packaged

Most heat pumps are split-systems—that is, they have one coil inside and one outside. Supply and return ducts connect to the indoor central fan.

Packaged systems usually have both coils and the fan outdoors. Heated or cooled air is delivered to the interior from ductwork that passes through a wall or roof.

Multi-Zone vs. Single-Zone

Single-zone systems are designed for a single room with one outdoor condenser matched to one indoor head.

Multi-zone installations can have two or more indoor heads connected to one outdoor condenser. Multi-zone indoor heads vary by size and style and each creates its own “zone” of comfort, allowing you to heat or cool individual rooms, hallways, and open spaces. This distinction may also be referred to as “multi-head vs. single-head” and “multi-port vs. single-port.”

How do I decide which kind of heat pump is right for my home? 

A qualified installer is your best guide, but if you want to learn more now, check out this buying guide.