Electrical guide
What a heat pump needs from your electrical system in a Michigan winter
A heat pump changes how your house uses electricity in winter. Knowing what it needs from the panel before the equipment is ordered avoids the most expensive surprises.
- Panel capacity first
- Backup heat explained
- Ducted vs ductless
By Zachary Keating, Electrical Guides Editor
Updated September 2026
Quick answer
A heat pump needs a dedicated circuit sized from its nameplate, a disconnect within sight of the outdoor unit, and in most ducted systems separate circuits for electric backup heat strips. The deciding question is panel capacity: backup heat can be the largest load in the house, so a load calculation should come before the equipment is chosen.
Why heat pumps change the electrical picture
A gas furnace uses a small amount of electricity to run its blower and controls; the heat itself comes from gas. A heat pump moves heat with an electric compressor, and in a Michigan winter it runs long hours. In a ducted system it also carries electric resistance strips that switch on during defrost and the coldest stretches. Together, those loads can be more than an older service was ever sized for.
That is why the electrical side deserves its own conversation, separate from the efficiency numbers on the brochure. The equipment can be excellent and still disappoint if the circuits feeding it are wrong.
The circuits a heat pump needs
Every heat pump outdoor unit needs a dedicated 240-volt circuit sized from the minimum circuit ampacity and maximum breaker size on its nameplate, not from a rule of thumb. Ducted systems add a circuit for the indoor air handler and one or more circuits for backup heat strips. Ductless mini-splits usually need one circuit per outdoor condenser, with the indoor heads fed from it.
Code also requires a disconnecting means within sight of the outdoor unit, so a technician can shut it off safely while working on it. Our heat pump electrical page covers how those circuits and disconnects are installed.
Backup heat strips: the load people forget
Backup heat strips are electric resistance heaters inside the air handler. They are simple and reliable, and they can draw a great deal of power. A strip package of 10 kW or more is common, which by itself can be a large share of a 100-amp service. When the strips run alongside the compressor, a water heater, a dryer and a range, an older service can be pushed past its limit.
Smaller strip packages, staged strips, or a dual-fuel setup that keeps a gas furnace for the coldest hours can all reduce the peak load. The right choice depends on the house, and it is easier to decide before the equipment is ordered than after.
Is your panel big enough?
A load calculation adds up the existing loads in the house and the new equipment at their rated values and compares the total with the service size. Many homes with 200-amp service can add a heat pump without trouble. Homes with 100-amp service often can add a mini-split, and sometimes a ducted unit with careful choices about backup heat or load management, but not always.
If the numbers do not fit, the options are load management, a smaller strip package, dual fuel, or a service upgrade. Our panel upgrade page explains what an upgrade involves and why it is sometimes the cheaper long-term answer.
Ducted, ductless or dual fuel
A ducted heat pump replaces or works alongside the furnace and uses the existing ductwork; it brings the largest electrical change because of the strips. A ductless mini-split heats specific rooms, often an addition, attic or cold bedroom, and usually adds one modest circuit. A dual-fuel system pairs a heat pump with a gas furnace and lets the furnace take over in deep cold, which keeps the electrical load closer to what the house already handles.
None of these is right for every house. The electrical facts narrow the choice quickly, which is why it helps to have them on the table early.
Getting the timing right
The smoothest heat pump projects start with an electrical visit before the HVAC contract is signed. The electrician checks the service, confirms the circuits the chosen equipment needs, and pulls the permit, so wiring is done and inspected by the day the equipment is set. Coordinating the two trades this way means the walls are opened once and the system starts up on the planned day.
If the system is already installed and the house is cold in January, the first things to check are whether the backup strips are connected and whether their circuits are sized correctly; our dedicated circuit work often starts there.
Related services
Services this guide relates to
Straight answers
Questions about heat pump electrical needs
Still unsure? Call (616) 699-4794 and ask a technician.
Yes, outdoor units run on dedicated 240-volt circuits sized from the nameplate.
Often 10 kW or more in ducted systems, which is a large load on an older service.
Often yes, since a single-zone mini-split usually adds one modest circuit.
A heat pump paired with a gas furnace that takes over in deep cold.
Yes, so the service and circuits are confirmed before equipment is ordered.
Backup strips that were never connected or are on undersized circuits are a common cause.
