Air source heat pumps can provide efficient cooling and heating for many Minnesota homes

April 15, 2021

Published April 15, 2021

Over the last few years, CUB has fielded an increasing number of calls from consumers interested in learning more about air source heat pumps. This blog provides an overview of resources for those interested in learning more about this technology and whether it could be a good option for their homes. We also have additional information in our online resource library.

What is an air source heat pump?

Your first question may be: what is an air source heat pump (ASHP)? Simple answer: It is a very efficient type of combined heating/cooling system that operates with electricity. The Clean Energy Resource Teams describes them this way: “ASHPs work like air conditioners to cool, and work in reverse to move warmth from outside air into your home to heat.”

Air source heat pumps are becoming more common in Minnesota due to technology improvements. The technology has been popular in other parts of the country that have mild to warm weather because they typically have been capable of heating a home when the outside temperature is 20 degrees or above while also acting as an air conditioner during warm weather. Luckily for Minnesotans, technology has improved, and now there are heat pumps that can operate in much colder temperatures. These “cold climate” air source heat pumps can work in below-zero conditions (some models down to -13 degrees). With our cold climate, it is necessary to have a backup system for times when it gets colder than their operating ability. A backup system could be a furnace, boiler, electric baseboard, wood stove, or other options capable of sufficiently heating a home when the temperatures are too low for an ASHP to work effectively.

Additionally, ASHPs can work with or without a central ducted heating/cooling system. For those who currently have central heating and/or cooling systems with duct work, an ASHP can be added to that system. Homes without ductwork, such as those who may heat with a boiler, electric baseboard heat, or a wood stove, can add what’s called a mini-split. Separate mini-splits can be installed on walls in strategic places to heat or cool the home effectively.

Right to left: a mini split verses ducted air source heat pump

Is an air source heat pump a good option for your home?

There are several factors to consider regarding whether an ASHP is a good option for your home. Saving money, being more comfortable, and reducing environmental impact are typically the key motivations we hear from consumers interested in ASHPs.

Saving money

Whether or not an ASHP pump will reduce your energy costs will depend on how you plan to use it: for heating, for cooling, or for both.

If you plan to use it for heating, and you currently heat your home with electric resistance heat (electric furnace or baseboards) or with propane, an ASHP will be less expensive to operate than those existing systems. A study conducted here in Minnesota by the Center for Energy and Environment found that, in most cases, an air source heat pump plus any type of backup system will be less expensive than solely relying on electric resistance or propane heat. They estimate a household that switches to an air source heat pump could save between 30-55% on heating costs depending on the fuel being replaced. Those currently using propane will be on the lower end of savings and those with electric resistance heating will realize the higher range of savings.

If you currently use natural gas, you should not expect to save money by switching to an air source heat pump for heating, due to the generally low cost of natural gas. Some households who have natural gas choose to install an ASHP for environmental reasons, which we will discuss later.

For cooling, the US Department of Energy explains that ASHPs are better at reducing humidity than traditional air conditioners and as a result will need less energy to cool a home effectively. As a result, they can be a good replacement for a central air conditioning system. How frequently you feel the need to cool your home will impact your costs as well. If you previously didn't have air conditioning and add an ASHP for cooling, you’ll end up spending more money on electricity than before, but you will be more comfortable.

Air source heat pumps can be expensive up front, so it’s helpful to understand how much money you can save using it that can help offset the purchase expense over time. Many electric providers offer rebates on air source heat pumps to help lower the upfront cost of purchasing high-efficiency equipment. Some electric utilities also offer special electric rates to reduce the expense to heat a home. Additionally, energy purchased to power primary heating sources is also exempt from sales tax between November and April so the electricity used to run your heat pump, if it is considered your primary heating source, will be exempt from sales tax.

Comfort

For homes without central air conditioning or the ability to install it, heat pumps can be a good option to cool a home and will likely improve the comfort of a home compared to relying on window AC units. As mentioned previously, heat pumps also do a better job of removing humidity than standard central air conditioners. When in heating mode, the air heated by an air source heat pump will be warm but not hot, and it will feel somewhat cooler than the air that you may be accustomed to from a forced-air system heated by a traditional furnace.

Environmental considerations

Heat pumps run on electricity. For those interested in reducing their carbon footprint, understanding the source of your electricity is key. The cleaner the electricity source, the less carbon is being used to run your heat pump for heating or cooling. If you are looking to decrease your carbon footprint further, many consumers have renewable energy options through their utility to purchase renewable energy beyond what their utility provides to offset their electricity usage. An air source heat pump powered by renewable electricity can be a good option for customers seeking to reduce their environmental impacts.

Other considerations

If you are thinking about an air source heat pump, consider how to best time the installation. In some cases, it’s ideal to install it when you might already need to replace a heating or cooling system.

If your current heating system is very expensive to operate, it may be advantageous to replace it and supplement it with an air source heat pump sooner than later.

For more information, we typically refer consumers to three sites that provide a good overview: The Clean Energy Resources Team, Center for Energy and Environment, and the U.S. Department of Energy.

Finally, we encourage people to talk to multiple contractors and get multiple bids. They can help you understand what options will work best for the physical characteristics of the home and your goals around installing an air source heat pump.

Please reach out to us if you’d like to talk through your situation. You can call 651-300-4701 ext. 2 or email me at carmenc@cubminnesota.org. We’re happy to refer to resources to help provide the information you need to make a good decision for your household.