Heat pump basics
A heat pump is a piece of electric HVAC equipment that provides both heating and cooling to your home. Heat pump technology is an advancement of traditional air conditioning technology. Traditional air conditioning works by moving heat one direction to keep an area cool. A heat pump can move heat both directions. This feature allows heat pumps to either move heat out of an area to keep it cool or move heat into the area to keep it warm.
Air source heat pumps (ASHPs) are the most common type of heat pump because of their relative affordability and ease of installation. ASHPs, like traditional air conditioners, transfer heat between inside and outside air. Other types of heat pumps exist, such as air-to-water, ground source, and water source, but are less common and more expensive.
The difference is whether the heat pump uses ductwork to deliver heating and cooling.
Ductwork carries heated or cooled air throughout a house. The conditioned air is delivered to rooms by vents or grates. Homes that have ductwork may have a furnace and/or central air conditioning. A ducted heat pump is a heat pump that uses ductwork to deliver conditioned air. A ducted heat pump replaces a central air conditioner (if one was previously installed).
Ductless (mini-split) heat pumps, however, do not need ductwork. This makes them ideal for homes that are heated by a boiler or electric baseboards. Ductless heat pumps use indoor units that are installed in living areas to condition the air. The most iconic style of indoor unit is the highwall, which looks like a horizontal box near the ceiling. Other styles of indoor units, like floor-mounted options, are also available.
You can read more about ducted and ductless systems, as well as other considerations, in this blog post.
Yes, heat pumps work in Minnesota. A heat pump plus a secondary heating source is a reliable HVAC setup to keep you comfortable during our state’s hot summers and long winters.
A heat pump’s performance determines the lowest temperature to which it can operate. Modern, variable speed heat pumps are better suited to our heating needs in Minnesota. Cold-climate heat pumps are a type of variable speed heat pump designed for high heating performance. Some cold-climate models can continue to provide heat into negative outdoor temperatures. Standard heat pumps (single-stage or two-stage) have more limited heating capabilities in comparison.
Most homes in Minnesota that have a heat pump need a secondary heating source to maintain comfort all winter.
The secondary heating source can be a gas system or an electric system. In some cases, your home’s existing heating system can serve this purpose.
The need for a secondary heating source is due to our very cold climate and the typical capabilities of heat pump technology. Heat pumps provide heat by extracting energy from outside and moving it inside. This process is very energy efficient in mild to moderate weather. While there is always energy in the outside air, heat pumps must work harder to gather that energy as temperatures drop. This gradually increases operational costs and reduces the amount of heat delivered to the home. A secondary heating source controls these potential issues. In a system together, a heat pump and secondary heating source provide reliability and comfort year-round.
The switchover temperature is the temperature at which your heating switches from the heat pump to the secondary source. Once installed, a heat pump is the primary heating system and provides heat down to the switchover temperature. Below the switchover, the secondary heating source turns on to maintain your thermostat setting.
Consider this example to illustrate:
A home has a heat pump and a gas furnace. The switchover is set to 15°F. Cool fall weather is approaching.
- From when heating is first turned on for the season and down to 15°F, the heat pump provides heating.
- When outdoor temperatures drop below 15°F, the heat pump turns off and the gas furnace takes over heating.
Contractors will recommend different switchovers for different equipment options. If you want to change the switchover temperature after the heat pump is installed, discuss it with your contractor during a service call. You may also be able to change the switchover yourself through your thermostat controls.
You can explore our Annual Energy Costs Chart to see the potential bill impacts of different switchovers.
The average operational life span of a heat pump is 15 to 20 years. You can maximize the life and performance of your heat pump by scheduling regular service and conducting simple home maintenance.
The homeowner experiences with heat pumps
Modern, variable speed heat pumps provide comfortable heating. The delivered air from a heat pump does feel different than a furnace. A properly sized, variable speed heat pump delivers less hot air for longer periods of time than a furnace. Through this operation, variable speed heat pumps save energy and maintain a comfortable, consistent indoor temperature.
Yes, you can set your thermostat back for periods of time with a heat pump (called “setbacks” in this section). However, if you want to maximize the energy savings from your heat pump, we recommend minor setbacks only.
With a traditional heating system, setting the thermostat back at night or while people are out for the day can help save energy. It seems counterintuitive, but the most energy efficient way to use a heat pump is default to set a consistent thermostat point. Heat pumps operate best when maintaining the same temperature for long periods of time.
That said, you can still choose to make setbacks if you would like. Setbacks within a few degrees have negligible effects on the heat pump's efficiency. This can be an option if you like your house cooler at night and still want to maintain good energy efficiency.
The exception is if you are away from home for a few days or more. A larger setback will still save energy with a heat pump in these cases.
A properly maintained heat pump will operate more efficiently and last longer. The best way to maintain your heat pump is to make sure the outdoor unit has good airflow. Other repairs and maintenance should be left to a contractor. Maintenance steps you can take include:
- Regularly clean or change the filter for the system.
- Clean debris off the outdoor coils.
- Keep the outdoor unit clear of snow accumulation.
- Keep plants and other blockages away from the outdoor unit.
The filter location depends on whether you have a ducted or ductless (mini-split) system. If you have a ducted system, the heat pump uses the same filter that the furnace does. If you have a mini-split system, each head has its own filter that can be cleaned.
Airborne seeds and other debris can accumulate on the outdoor coils, preventing proper airflow. You can use a common hose (not a pressure washer!) to spray the debris off the coils.
The outdoor unit should have some separation from obstructions that limit its airflow. Plants and shrubbery should be trimmed back a couple feet from the heat pump. Take care not to install decking, masonry, fences, or other solid objects within five feet of where the outdoor unit discharges air. For a ducted unit, air is usually discharged up. For a mini-split, air is usually discharged sideways.
Finally, keep snow from piling up on the outdoor unit. Snow blocks airflow and can also encourage ice buildup on the coils.
A contractor will propose locations for the mini-split indoor units to meet your heating and cooling needs. Mini-split indoor units can vary in style and can be installed on the wall, floor, or ceiling.
Defrost cycles are a normal part of heat pump operation but can surprise people who are new to owning one.
Heat pumps enter defrost mode when there is a risk of frost buildup on the outdoor unit’s coils. Too much frost buildup can damage a heat pump by restricting airflow to the outdoor unit. Frost buildup is more likely during wintery precipitation and when the outdoor temperature is between 25°F and 45°F. Defrost cycles typically last 10 minutes and occur at most in 30-minute intervals.
There are a few new sights and sounds to expect during a typical defrost cycle. The outdoor unit will emit a metallic drone that is louder than typical operation. As the defrost cycle melts the frost, you may see water drip, icicles form, or steam rise from the outdoor unit. The sounds may peak as the defrost cycle completes and the heat pump resumes normal operation. Take care when walking around heat pumps in the winter, as there may be frozen meltwater from defrost cycles underfoot.
You can help reduce the need for defrost cycles by maintaining good airflow to the outdoor unit. Keep snow from piling up where it would block airflow.
If your heat pump seems to be in defrost too frequently or the behavior is atypical, contact your contractor for assistance.
Contractor recommendations and equipment options
A quality contractor will provide heat pump options tailored to your home and goals. We recommend you collect quotes from at least three contractors for a good slate of options.
The ASHP Collaborative Preferred Contractor Network can connect you with a quality heat pump installer. Preferred Contractor Network members have attended training courses, provided proper license documentation, and demonstrated quality installations.
Visit the Preferred Contractor Network to find the nearest member.
If you want to source bids from more contractors or do not have a Preferred Contractor Network member in your area, read our 4 tips blog post. You can also contact your local utility to ask if they have their own list of rebate-eligible contractors.
There are many reputable heat pump manufacturer brands available. However, rather than starting your search with brands, we recommend finding a few quality contractors to collect quotes from first. Contractors have a selection of brands they install and will offer a few model options for your home. This approach is easier than trying to weigh dozens of variations of brands, models, and specifications yourself.
Visit the Preferred Contractor Network to find the nearest quality contractor.
A heat pump’s performance has a lot to do with its type of compressor. Compressors allow heat pumps to move refrigerant and heat between the inside and outside. Generally, the more speeds a compressor can run, the more efficient the heat pump is.
Single-stage units can only run at one speed. They are either turned off or all the way on. Single-stage units are the most affordable upfront and can be compatible with most furnaces. However, they have higher operational costs and the least ability to provide heat.
Two-stage units have a low and high speed. This improves their ability to operate efficiently in a wider range of outdoor temperatures. The two speeds also allow for better indoor temperature stability, which is a key measure of comfort.
We refer to single-stage and two-stage heat pumps as standard equipment. Standard heat pumps may make sense if you:
- Want the lowest cost heat pump options
- Have natural gas and do not plan to use the heat pump for much heating
- Want a heat pump that can more easily integrate with your existing furnace
Modern, advanced heat pumps have variable speed compressors. "Inverter-driven compressors" and "variable capacity" are other names for this technology. Rather than having one or two speeds, variable speed heat pumps can modulate their speed in many small steps. This allows these heat pumps to maintain steady indoor temperatures for longer periods of time, for the least energy. Variable speed heat pumps can operate efficiently at the highest and lowest outdoor temperatures. Additional benefits of variable speed units include quieter operation and better dehumidification.
We strongly recommend inverter-driven heat pumps if you:
- Want the option to choose between electric and gas heating as prices change
- Have expensive heating, like electric baseboards or a propane system, and want lower heating bills
- Want to decarbonize your home as much as possible
The increased performance of a variable speed ASHP does come with a higher price tag. However, you can stack incentives together to greatly reduce upfront costs. Many incentives have efficiency specification requirements for eligibility. Variable speed heat pumps (especially cold climate units) are the most likely to qualify for the largest incentives.
The term “cold climate” describes heat pumps that are specifically designed to provide heating in very cold weather. A heat pump can qualify as cold climate if it maintains a high efficiency at 5°F and has a variable speed compressor.
However, cold climate is not an industry-standard definition. Asking a contractor to quote a cold climate unit can be a good shorthand if you want a heat pump with maximum heating capacity. Because of their high efficiency, cold climate heat pumps are likely to meet most incentive eligibility requirements. We still recommend you confirm with your contractor which incentives your intended heat pump can qualify for.
Heat pump sizing refers to the capacity of a heat pump to provide heating or cooling. This capacity is measured in tons. The more tons a heat pump has, the more heating and cooling it can supply. Common heat pump sizes for a single-family home range from 2 to 4 tons. However, more tons are not always better. The right sized heat pump for your home will do a better job keeping you comfortable at the lowest operational costs.
- A larger sized heat pump may make sense if you have:
- A large home
- An older home or one that is not well insulated or air-sealed
- A goal to use your heat pump for as much heating as possible
- A smaller sized heat pump may make sense if you have:
- A smaller home
- A newer home or one that is well insulated and air-sealed
A quality contractor will perform different measurements on your home to recommend a properly sized heat pump. Visit our Preferred Contractor Network to connect with a qualified contractor in your area. If you want to learn more technical considerations for discussing options with contractors, refer to our blog post, 4 Tips for Choosing a Heat Pump Contractor.
Yes. There are a few options for pairing a new heat pump to an existing furnace. Your options include:
- Single-speed heat pumps, which are compatible with many furnaces. Single-speed heat pumps have lower upfront costs, but also lower efficiency and performance.
- Variable speed heat pumps designed to integrate with any furnace. These heat pumps are likely to have higher efficiency and performance than single-speed units but less than a new, matched heat pump and furnace set. A couple examples are the Bosch IDS and Mitsubishi Intelli-HEAT.
- A heat pump that is the same brand as your furnace. Depending on your furnace brand and model, your contractor may be able to recommend one or more heat pump options that could pair with it.
Talk to a quality contractor for heat pump options that can work with your existing furnace.
There are a couple of scenarios when you may want to consider replacing your furnace when you add a heat pump.
- If your furnace is over eight years old. The average furnace lifespan is 15–20 years. If your furnace is getting close to replacement age, it may be worth replacing it sooner rather than later. Replacing your furnace when it fails is often an expensive hassle with limited options for equipment to choose.
- If you want to maximize the performance of a variable speed heat pump. Variable speed heat pumps are unlikely to operate at their peak efficiency when paired with an older furnace.
Electrification and carbon reduction
Yes. Over the typical lifespan of an HVAC system, a heat pump can significantly reduce your household emissions. In other words, heat pumps are the clear eco-friendly choice compared to fossil fuel equipment.
The core reason is because electricity is becoming a greener fuel for homes than gas. Thanks to recent legislation, Minnesota electric utilities are required to provide carbon-free electricity by 2040. This is a huge change and builds on momentum already at work. The electricity we get from power plants has been getting greener as we have retired coal plants. And the amount of renewable energy on the grid has quickly increased.
How green a heat pump is now, and the rate it gets greener, depends on your electric utility. Some utilities have cleaner grids than others. Some have plans to decarbonize quicker to reach the carbon-free 2040 mandate. Despite the variations, offsetting part (or all) of your heating needs to a heat pump is a highly effective way to cut household carbon emissions over time.
An all-electric system is possible in Minnesota. An all-electric system maximizes your potential to reduce emissions over time. You may save money on heating bills by switching to an all-electric system if you currently use propane. However, if you currently heat with natural gas, an all-electric system is likely to be significantly more expensive to operate.
The main components of an all-electric systems are a cold climate heat pump, supplemental electric resistance heating, and an air handler. The furnace is removed.
In an all-electric system, the heat pump operates to as low a temperature as possible. The electric resistance heating turns on to contribute more heat when needed. That said, electric resistance heating is expensive to operate. This makes it important to install a cold climate heat pump to maximize how much heating is supplied by the heat pump itself. Minimizing the need for resistance heating tempers winter energy bills.
Very energy efficient homes are the best candidates for all-electric systems. These homes need little heat to stay comfortable, which makes it much more viable for most or all heating needs to come from a heat pump. You can read about how to make your home more energy efficient in our blog post about preparing your home for a heat pump.
Cost and finance
Heat pumps are currently more expensive than standard air conditioners or furnaces. However, heat pumps will likely become significantly more affordable in the next couple of years.
New and increased incentives will eventually include:
- Tax credits (available now)
- Rebates from utilities (available now)
- Rebates from the federal government
- Rebates from the State of Minnesota
Pricing for heat pumps varies widely based on your home needs, the contractor, and the equipment. Getting estimates from multiple qualified contractors is the best way to review the cost ranges. Visit our Preferred Contractor Network to find a qualified contractor in your area.
A heat pump’s impact on your energy bills will depend on your current HVAC equipment, what fuel you use for heating, and the types of rates offered by your electric utility.
Some utilities offer attractive dual fuel electric rates for customers using a heat pump with a fossil fuel secondary system. Dual fuel electric rates are often significantly lower than standard rates. Some utilities also offer a special rate for electric space heating if the home’s primary heat source is electric. As an example, Xcel Energy allows customers to request their electric space heating rate if they have a dual fuel system with a switchover temperature at or below 35°F.
Heat pumps are most likely to save money if you currently use propane or electric resistance heat. Generally, the more you can cut propane or electric resistance use by heating with a heat pump, the better the savings.
Heat pumps are unlikely to save money if you currently heat with natural gas unless your utility offers a dual fuel rate. However, you can keep your heating bills similar to before if you use the heat pump down to between 45°F and 25°F.
The local price of electricity and fuel significantly impacts these general statements. Visit our interactive cost of heat comparison chart for more specific estimates.
There are a variety of incentives currently available now:
- Tax credits
- Utility rebates
- Manufacturer rebates (potentially)
Visit our Incentives and Financing page for the most up to date information on what is available in your area.
The State of Minnesota will contribute rebate dollars toward heat pump installations that have already earned a rebate from the Inflation Reduction Act. However, the Inflation Reduction Act rebates are not yet available, and the timeline is unknown.
We unfortunately do not know when the Inflation Reduction Act rebates will be available. You can read our blog post for commentary about whether someone may want to buy a heat pump now or wait.
The Inflation Reduction Act rebates are not retroactive. Heat pumps installed before the rebates are officially live are not eligible for rebates.