A dual-fuel system, also called a hybrid system, pairs an electric heat pump with a gas furnace. The heat pump heats your home when it is mild outside and cools it in summer. The furnace takes over when it gets too cold for the heat pump to heat efficiently. For many Minnesota homes with ductwork and natural gas service, this is the most practical way to add a heat pump without giving up reliable heat in January.
How a dual-fuel system works
The heat pump's outdoor unit replaces a central air conditioner. Its indoor coil sits on top of the furnace, and both share the same blower and ductwork. A thermostat or control board decides which one heats the house.
- Mild and cool weather: the heat pump moves heat from the outdoor air into your home using electricity.
- Deep cold: the controls lock out the heat pump and run the gas furnace instead.
- Summer: the heat pump runs in cooling mode like a central air conditioner.
The U.S. Department of Energy's heat pump systems page describes this setup as one where the furnace takes over during colder temperatures.
Switchover temperature: the most important setting
The switchover (or balance) temperature is the outdoor temperature at which the system stops using the heat pump and starts using the furnace. This one setting controls how much of your winter heat comes from each fuel.
- A higher switchover means the furnace runs more often. This can make sense with an older or smaller heat pump, or when gas is much cheaper than electricity for your home.
- A lower switchover means the heat pump does more of the work. Cold-climate heat pumps can heat at much lower temperatures than standard models.
Research from Minnesota's Center for Energy and Environment found that installers commonly set lockouts around 25–35°F on non-cold-climate heat pumps. In its field assessment of cold-climate air-source heat pumps, ducted systems were set to switch over at 10°F, and at 5°F in some colder homes. The report notes that a higher setting leaves some of a cold-climate unit's heating capacity unused.
Utility rules can also set limits. For 2026, CenterPoint Energy's ducted air-source heat pump rebate for Minnesota requires a gas furnace rated 92% AFUE or higher and a switchover temperature set at 40°F or lower.
The right setting for your home depends on your heat pump's capacity at low temperatures, your home's heat loss, and your electric and gas rates. Ask your contractor to explain how they chose it.
Equipment requirements and compatibility
Not every heat pump works with every furnace. Before you plan a dual-fuel system, know these points:
- Furnace blower: variable-speed heat pumps work best with a furnace that has a variable-speed or multi-stage blower. Many older furnaces have single-speed blowers.
- Brand matching: the Center for Energy and Environment report notes that manufacturers and installers often specify that the furnace and cold-climate heat pump be the same brand for proper control integration.
- Controls: you need a thermostat or communicating control that supports dual fuel and an outdoor temperature sensor.
- Coil and ductwork: the indoor coil must match the outdoor unit and fit the furnace cabinet. Undersized ducts reduce heat pump performance.
- Electrical: the outdoor unit needs its own circuit and disconnect.
If your furnace is near the end of its life, it may be simpler to replace both at once. If your furnace is newer, a contractor can check whether it can work with a heat pump.
Pros and trade-offs
Benefits:
- You keep a gas furnace for sub-zero cold snaps and power-outage planning with a generator.
- You use less gas through spring, fall and mild winter days.
- One outdoor unit handles both cooling and much of your heating.
Trade-offs:
- You maintain two heating appliances instead of one.
- The heat pump runs year-round, so it collects more operating hours than an air conditioner.
- Savings depend on your utility rates. Xcel Energy and other utilities may offer electric heating rates that change the math, so check your rates before you choose a switchover setting.
What you can safely check yourself
- Watch the thermostat display. Many dual-fuel thermostats show whether the heat pump or the furnace is running. Note the outdoor temperature when it changes.
- Replace the furnace filter. Both the heat pump and the furnace use the same blower and filter. Check it monthly in winter.
- Keep the outdoor unit clear. Remove snow from around and on top of the unit by hand or with a broom. Do not chip ice off the coil.
- Clear furnace vent pipes. Keep snow away from the high-efficiency furnace's plastic intake and exhaust pipes.
- Test your CO alarms. A gas furnace is still part of the system, so keep carbon monoxide alarms working on every level.
If you smell gas, do not touch the furnace or thermostat. Leave the house on foot, avoid light switches and phones inside, and call 911 and CenterPoint Energy once you are outside.
When to call a professional
Book a consultation when your air conditioner or furnace needs replacement and you want to compare a dual-fuel setup with a standard furnace and air conditioner. Call for service if the furnace runs on mild days when the heat pump should be heating, if the heat pump runs but the house cools down in deep cold, or if the thermostat shows a fault. Krinkie's can review your existing gas furnace and explain your heat pump options.
Common questions
What is a good switchover temperature for a dual-fuel system in Minnesota?
There is no single right number. It depends on your heat pump's cold-weather capacity, your home's heat loss and your gas and electric rates. CenterPoint Energy's 2026 heat pump rebate requires a setting of 40°F or lower.
Can I add a heat pump to my existing furnace?
Often, yes, if the furnace is in good condition and its blower and controls are compatible with the heat pump. A contractor should check the furnace model, coil fit and ductwork first.
Does a dual-fuel system still need furnace maintenance?
Yes. The gas furnace still burns fuel and needs an annual inspection of its burners, venting and safety controls, along with a check of the heat pump.