A lot of heat pump quotes come with a surprise line: service upgrade to 200 amps. That can add thousands of dollars and weeks of waiting for the utility.
Sometimes it is needed. Often it is driven by oversized electric backup heat that a real heat loss would have shrunk. Here is how to tell the difference.
Needs its own 240 volt circuit. Most fit on an ordinary service.
The big one. A 10 kW strip draws roughly 42 amps at 240 volts. Oversize the backup and you oversize the electrical load.
Range, dryer, water heater, EV charger. A panel that was fine yesterday can be tight tomorrow.
Backup heat sized to the biggest kit available instead of the real gap at your design temperature. Right-size it and the panel question often goes away.
From a real heat loss, not the old furnace size.
Only the gap at design temperature. See balance point and backup.
A hybrid system uses gas for backup, not electric strips. See hybrid design.
Some devices let big loads take turns. Your electrician knows what is allowed.
A licensed electrician does the load calculation and decides what your service can carry.
Electrical work needs its own permit through the Electrical Safety Authority.
Gives the electrician the real heating numbers to work with.
Deciding whether backup is gas, electric or wood changes the answer.
Heat loss first. Then the heat pump size and backup size. Then the electrician’s load calculation with real numbers. Then decide on the panel.
Doing it backwards means paying for a service upgrade to carry backup heat you did not need. For the heat pump permit itself, the building department may also want the ventilation summary (RMVDS) and the design. See heat pump permits.
Quoted a panel upgrade? Get the heat loss first. It may shrink the backup heat and the upgrade with it.
Get Free Quote →Not always. Many heat pumps fit on a 100 amp service. What often tips the scale is oversized electric backup heat. A licensed electrician does a load calculation to decide. Right-sizing the heat pump and the backup from a real heat loss often avoids the upgrade.
A lot. A 10 kW strip heater draws roughly 42 amps at 240 volts. Size the backup to the real gap at your design temperature, not to the biggest kit the installer has.
A licensed electrician, using a load calculation under the electrical code. Electrical work needs its own permit through the ESA.
Sometimes. Right-sizing the heat pump and backup, keeping a gas furnace as backup, or using a load management device can all help. Ask your electrician what fits your house.
Yes. A heat pump, electric backup and an EV charger all on a 100 amp service can be a squeeze. Plan them together, not one at a time.
It tells you the real heating load, which sets the heat pump size and the backup size. Smaller, correct equipment means a smaller electrical load. See backup heat sizing.
Send a floor plan or drawings. We calculate the heat loss so your heat pump and backup are sized right before the electrician runs the panel numbers.