Electric air-source heat pumps are an energy-efficient way to heat and cool homes and businesses in moderate climates. Air-source heat pumps use electricity to move heat from a cool space to a warm space, making the cool space cooler and the warm space warmer. Because they move heat rather than generate heat, heat pumps can provide equivalent space conditioning at as little as one-quarter of the cost of operating conventional heating or cooling appliances such as baseboard heat and air conditioners.
In Western North Carolina, heat pumps are a good option for heating and cooling. However, when outdoor temperatures dip below about 30 degrees Fahrenheit, a traditional heat pump’s technology can’t keep up with heating needs. It relies on its auxiliary heat strips, which is a very inefficient method of heating – resistance heat, which is akin to using a toaster to heat a space. Variable-speed and ductless mini-split heat pumps’ technology reduces and can negate the need for these heat strips, making them a wise option in colder climates like WNC’s that experience a winter peak energy demand.
Variable-speed heat pumps work just like a traditional single-speed heat pump. Heat is pulled from either inside or outside and then dumped either inside or outside, depending on whether it’s heating or cooling. Whereas traditional heat pumps have one speed and are either on or off, variable-speed heat pumps can be turned on like a light with a dimmer switch – operating at a variety of speeds to meet the heating and cooling requirements. This enables it to meet the temperature demands set at the thermostat much more efficiently since they’re not stopping and starting as often. Starting up is when a heat pump uses the most energy. Variable-speed heat pumps often run for longer durations but at levels that use less energy such as 10-50% capacity, which can help with dehumidification and air filtration.
Ductless mini-splits are popular heating and cooling systems throughout the world, and are gaining popularity in the U.S. Ductless mini-split heat pumps utilize variable-speed technology but don’t rely on ducts. Instead, wall- or ceiling-mounted blower units are installed in the rooms where heating and cooling is needed. The ductless nature of these systems in itself saves significant energy; the Department of Energy estimates that more than 30% of the energy consumption used in heating and cooling is lost through ducts. Ductless systems use variable speed compressors to continuously meet the demand of the heating or cooling load. This avoids the inefficient on/off cycling of conventional electric resistance and central heating systems, which is commonly associated with uncomfortable temperature variations and high energy consumption.
Variable-Speed and Ductless Mini-Split Heat Pumps Support a Clean Energy Future
Because heating and cooling buildings and homes comprise 30-35% of our region’s energy use, and the fact that our mountainous region experiences a winter peak demand, utilizing variable-speed heat pumps is an important step toward a cleaner energy future. Traditional electric heat pumps use a tremendous amount of energy to heat when it’s below about 30 degrees Fahrenheit by relying on back-up resistance heat strips. Variable-speed and ductless mini-split heat pumps make use of inverter technology to allow them to heat efficiently down to temperatures as low as 5 degrees Fahrenheit in some cases. Reducing the energy we use to heat and cool our buildings, especially during times of peak energy demand, helps avoid the need for new power plants in our region.
Rebates and Incentives
Local Installers and Resources
- Any HVAC contractor in WNC should be able to provide you with options for variable-speed and mini-split heat pumps as well as any available incentives.
Links and Videos with More Information
For more detailed information on this technology, we recommend visiting
- Pick HVAC’s Heat Pump page
- The Department of Energy’s page on heat pumps
- Green Built Alliance blog post on variable speed heat pumps by Amy Musser
- Forbes article on mini-split heat pumps