High Efficiency Heat Pumps

More than 45,000 high efficiency ductless heat pumps have been installed in Maine homes and businesses over the past five years. Long used for cooling in warm climates, heat pumps are now one of the most popular technologies for heating in cold climates. Efficiency Maine offers rebates for high-efficiency ductless heat pumps for residential and commercial customers.

How do they work?

In winter, ductless heat pumps extract heat from outside air and deliver it indoors. Because they are moving heat rather than generating it through combustion or electric resistance, heat pumps can achieve efficiencies well above 100%. Long used for cooling in warm climates, heat pumps are now able to provide efficient heating in cold climates even at outdoor temperatures as low as -15 °F.

Ductless heat pumps consist of an outdoor unit connected to indoor air handlers by refrigerant lines, which carry heat between the two.

There are four types of indoor units:

What are the advantages?

• Low-cost heat – Heat pumps are one of the lowest cost sources of heat at current energy prices. Click here to compare heating costs of different heating systems.
• Comfort – With advances in controls, heat pumps can maintain very constant temperatures.
• Safety – Because heat pumps are electrically powered, there is no risk of combustion gas leaks.
• Air quality – Heat pumps filter indoor air all year and dehumidify it in the summer, improving air quality.
• Room-by-room control – When installed with multiple indoor units, heat pumps allow for room-by-room temperature control.
• Low-cost air conditioning – Today’s best heat pumps are twice as efficient as typical air conditioners.

What are other considerations?

• Cold temperature performance – Because heat pumps extract heat from outside to provide warm air inside during the heating season, as it gets colder outside, the heat pumps work harder to keep up, making them less efficient. For example, a system that delivers four units of heat for every unit of electricity at 50°F, may deliver only two units of heat for every unit of electricity at temperatures below zero. There is evidence of the highest performance units operating and providing heat even below -15 °F in Presque Isle. But if the temperature drops low enough, the system may turn off completely. Be sure to check out the minimum operating temperature listed for your heat pump. If you experience prolonged periods below that temperature, consider a secondary backup heating system to maintain your desired comfort level through the chilliest nights. If you use a backup system, just be sure to switch back to your heat pump once temperatures rise, or you could quickly lose your energy savings.
• Air movement – Heat pumps do not bring fresh air into the home, but they do recirculate air. Air blowing directly on you can increase comfort during the cooling season, but can be uncomfortable during the heating season. Take a look at Efficiency Maine’s ductless heat pump user tips for recommended fan settings for the heating and cooling season.
• Heat distribution – Ductless heat pumps rely on air movement to distribute heat. This can make it hard to get heat around corners and into dead-end spaces. Take a look at Efficiency Maine’s ductless heat pump user tips and installation considerations to learn how to get the most from a heat pump.
• Interactions with the primary heating system – If you are thinking about using a heat pump along with another heating system, make sure to locate the heat pump where it won’t conflict with the other system’s thermostat. This kind of conflict could result in one system preventing the other from running. This is not a risk if you are using a heat pump as your only heating system. Take a look at Efficiency Maine’s ductless heat pump installation considerations for tips on where to install your heat pump.
• Aesthetics – Indoor and outdoor units can be more visible than components of other heating systems.

Useful Ductless Heat Pump Links