Heat Pump Advice

Ask Alexis

Is a heat pump right for your home?

Alexis Troschinetz

Heat pumps have received a lot of press as new and existing incentives draw attention to their role in improving home energy efficiency and reducing energy costs for Minnesotans.

Most Minnesota electric utilities offer rebates on heat pumps and the federal government currently offers a tax credit for up to 10% of project costs.

Beginning in 2023, heat pump projects will be eligible for tax credits and rebates through the Inflation Reduction Act. Visit our Guide to the Inflation Reduction Act to learn about emerging incentives for clean energy projects as we learn more about them. 

But is a heat pump right for your home? Ask Alexis tackles some common heating and cooling situations that folks ask about, and you can submit your question to Alexis for a future segment of this feature. 

DECEMBER 2022

HOME ENERGY ASSESSMENTS + WEATHERIZATION

Q: I noticed something among the more than a dozen folks asking about heat pumps for their homes: About half have not had a home energy assessment to understand whether their home could use more insulation or sealing leaks to improve air tightness. You might have wondered whether a home energy assessment and weatherization are necessary before getting air source heat pumps for your home. As is the case many times, it depends.

A: The time is right: Before upgrading or making significant changes to a home’s heating and cooling equipment is a great time to improve home insulation levels and make the home more air-tight. By doing so, it may save on the initial cost of heating and cooling equipment by being able to go with a smaller sized system than you might have without any weatherization.

There are many benefits to home energy assessments and weatherization: A home energy assessment uncovers energy waste you may not have known was happening in your home and gives you clear steps you can take to make improvements. Weatherization will not only improve your home’s comfort, reduce drafts and cold spots, and have lasting benefits in both heating and cooling seasons, but it can prevent structural damage from ice dams, too.

There are definite money-savings for homes heated with electric and/or propane: If your home is currently heated with electricity, with a cold climate air source heat pump, you could see 55% bill savings. For propane, it’s 30% bill savings or more. So, while a home energy assessment and weatherization is what I would typically recommend ahead of an air source heat pump for heating purposes, you will see operating cost-saving benefits if your home is heated with electric and/or propane, even if assessing and weatherizing are skipped.

Home energy assessments and weatherization are strongly encouraged for homes heated with natural gas: For Xcel Energy and/or CenterPoint Energy customers, home energy assessments are available through Home Energy Squad. For all others, check with your gas or electric utility to see what home energy assessment programs they have available. As we turn to heating more homes with electricity in Minnesota, we want to be sure we are doing so in a way that is beneficial to your own energy bills and also to the energy system as a whole. That’s why the Inflation Reduction Act (IRA) includes home energy audits and weatherization. Since the IRA incentives will be in place for 10 years, you can take the time needed to get your home looked at and improved before adding air source heat pumps for heating.

Do-It-Yourself is great, too! If you don’t have access to a home energy assessment where you live, you may want to do a self-assessment. Or, simply see what you can do to improve your home’s air tightness by taking steps yourself [PDF] like adding weather stripping around doors, re-sealing windows, spraying foam around openings into the house with gaps, and insulating dryer vents.


RADIATORS + WINDOW AIR CONDITIONING UNITS

Q: “My 1912 home has a natural gas-fueled boiler for radiators. In the summer, I use window air conditioning units. From a home energy visit, I learned that my home’s insulation levels and air tightness needed to be improved and I’ve since made changes. What are my options for air-to-water heat pumps that could utilize my existing radiators?”

—Turn-of-the-(last)-century homeowner

A: I have a “now and later” response for you.

For now, the proven system that works in Minnesota for your home type is a ductless or mini-split air source heat pump. This would be a good time to assess with a contractor where to place the indoor heads of a mini-split system. You likely will want an indoor head in the main living area and in occupied bedrooms. Mini-splits will either save you a lot of effort each spring and fall installing and removing window A/Cs, or if you leave the window A/Cs installed all year, you will not have those heat losses adding up all winter. Mini-splits also are much quieter and offer better dehumidification than window A/Cs.

Illustration of a mini-split air source heat pump

When it is 35 degrees or warmer outside, you could cost-effectively operate the mini-splits as your primary heating system (depending on the efficiency of each heating system and the costs of natural gas and electricity). So, this would be best in the fall or spring, offering you the ability to run your boiler heating system a few weeks less each year. (If operating in fall and spring only, you wouldn’t necessarily need a cold-climate air source heat pump.)

Based on current energy prices, your boiler will be the more cost-effective primary heating system once it drops below 35 degrees outside. The boiler can be made the primary heating system by setting it up to 4 degrees cooler than the temperature setpoint of the mini-splits (for example, set the boiler at 67 degrees and the mini-splits at 70 degrees). If you plan to operate the mini-splits in this way and through the winter, you’ll want a cold-climate air source heat pump. Operating the two systems in this way also makes “zoned heating” possible–keeping areas that are seldom used a little cooler. Since the mini-splits and boiler will have separate thermostats, you can also ask your contractor the best strategy to cost-effectively operate both systems to keep your home comfortable.

For later, there may be air-to-water heat pump equipment that would be compatible with your radiator. A study is currently underway to assess how air-to-water heat pumps may work in Minnesota with radiators and the results are expected in 2023. The most comprehensive list of air-to-water heat pump product specifications is from the Efficiency Vermont rebate program [PDF] and Otter Tail Power is currently offering rebates on this type of system in Minnesota (thanks to the MN ASHP Collaborative for sharing this information).

Also for later, you may be able to replace window A/Cs with window heat pumps, which is currently being tried in New York City’s public housing. This hasn’t yet been studied or tried in Minnesota, but it is something to keep eyes on.


NOVEMBER 2022

ELECTRIC BASEBOARD + WOOD-BURNING STOVE

Q: “I heat my home with electric baseboard heat. It can get expensive and so I also heat with a wood-burning stove. Is an air source heat pump right for my home?”

—Minnesota Northwoods resident

A: Yes! By converting your home’s primary heating system to an air source heat pump, you could save 55% on the portion of your electric bill that goes to heating your home. Since your home doesn’t have ductwork, the type of air source heat pump you would have installed is called a mini-split or ductless system. 

Illustration of a mini-split air source heat pump

Depending on the size of your home, there would be one or two outdoor compressor units. Multiple indoor units (sometimes referred to as “heads”) will be connected to the outdoor unit(s). A connection between the indoor units and outdoor unit(s), called a line set, runs on the outside of your home and looks like gutter downspouts. The indoor units can be mounted on the upper part of a wall, or there is another style that sits closer to the floor and is about the size of a radiator. Indoor units would be installed in spaces like the living room, bedrooms, and any other rooms that may not be very well connected to these spaces. 

Ideally, you’ll want to get 2-3 bids from skilled contractors. These contractors will be able to identify a set-up that will strike a balance between performing well for your home and keeping the total project costs reasonable. You would keep your electric baseboards in good working order for use on the coldest days of the year and you would get to use the wood stove only when you wanted to and not feel as much like you need to use it. As an added bonus, the mini-splits will be able to cool and/or dehumidify your home in the summer months. 

Visit the Air Source Heat Pump Collaborative Preferred Contractor Network for help finding an experienced HVAC contractor in Minnesota. 

Preferred Contractor Network


AIR SOURCE HEAT PUMP VS CONVENTIONAL AIR CONDITIONER

Q: “My home has a 25 year old air conditioner and a 5-10 year old forced air, natural gas furnace. I mostly want more efficient cooling, since my air conditioner is not going to last much longer. Should I be buying an air source heat pump instead of a conventional air conditioner?”

—Minnesota State Fair EcoExperience Enthusiast

A: Yes! Since your home has ductwork that is already being used for your forced air heating system, you most likely will want to replace your very old central air conditioner with an air source heat pump. 

The heat pump will provide cooling in the warm months of the year. You will be getting a new piece of equipment that looks like the current outdoor compressor, but it will be a lot more efficient. Bonus: The heat pump can also provide efficient heating in the spring and fall! Heat pumps cost roughly the same as a natural gas furnace when outdoor temperatures are between 25°F and 45°F.

Since your furnace hasn’t yet reached the end of its life, ask heating and cooling contractors whether there are any outdoor compressor units that would be compatible with your furnace’s air handling system.

illustration of an outdoor compressor unit for an air source heat pump

If not, this may mean replacing equipment in addition to the outdoor compressor, in order for the entire system to work together. I recommend that you get 2-3 bids from skilled contractors.) Once all compatible equipment is installed, two heating systems (forced air furnace and central heat pump) will be controlled through a single thermostat for your heating and cooling needs throughout the year.

Visit the Air Source Heat Pump Collaborative Preferred Contractor Network for help finding an experienced HVAC contractor in Minnesota.

Preferred Contractor Network