The electrical side of a heat pump install

Heat pumps are going into Lower Mainland houses at a pace we haven’t seen before, and a pattern has come with them. The HVAC quote covers the equipment and the install. Then someone looks at the panel, and there’s a second conversation nobody budgeted for.

It’s an avoidable surprise. Here’s what the electrical side actually involves and how to find out where you stand before you sign anything.

Two loads, not one

The heat pump itself is usually the smaller half of the story.

The outdoor unit needs a dedicated 240-volt circuit, and the size depends heavily on what you’re installing. A single-zone mini-split can be modest. A ducted whole-home system draws considerably more. The unit’s data plate gives the required circuit ampacity and maximum overcurrent protection, and those numbers are what the circuit gets designed around, not a rule of thumb.

The part that catches people is the backup or auxiliary heat. Many ducted systems include electric resistance heat strips in the air handler for the cold snaps when the heat pump alone can’t keep up. Those strips can pull more than the heat pump does. If your install includes them, that’s the load that decides whether your service is big enough, and it’s the one that gets glossed over in a quote that just says “electrical by others.”

Ask your HVAC contractor for the full electrical requirement including auxiliary heat, in writing, before you get pricing on the wiring. If the answer is vague, that’s your signal to slow down.

Whether your service can carry it

This is the actual question, and it’s arithmetic rather than opinion. A load calculation adds up your existing service load and the new equipment against the capacity of your service.

Roughly speaking: a 200-amp service in a house that isn’t already stacked usually absorbs a heat pump without drama. A 100-amp service often can’t, particularly if you already have an electric range, an electric dryer, and an EV charger, or if you’re adding a charger next. We went through how that math works in how many amps does my house need.

There’s a middle case worth knowing about. Sometimes the service is adequate but the panel is physically full, or it’s an older panel with a poor track record. Neither of those is a capacity problem exactly, but both mean panel work before the heat pump lands. If yours is a Federal Pacific or Zinsco, you’ll want to deal with that regardless.

When the answer is that the service needs to grow, that’s a panel and service upgrade, typically $4,000 to $6,000 depending on the service size, where the panel sits, and what BC Hydro’s side of it looks like. It’s a real number to fold into the project rather than a surprise at the end.

What the wiring job includes

For a straightforward install with capacity available:

• A dedicated 240-volt circuit from the panel to the outdoor unit, sized to the data plate.
• An outdoor-rated disconnect within sight of the outdoor unit, which is both a code requirement and the thing a service tech will thank you for.
• A separate circuit for the indoor air handler, and additional circuits for the auxiliary heat if it’s included, since strip heat is frequently fed independently.
• Low-voltage control wiring between the thermostat, the indoor unit, and the outdoor unit, usually coordinated with the HVAC crew.
• Weather-rated cable, boxes, and penetrations for the outdoor portion.

The run matters here the same way it does for any large outdoor load. A unit tucked beside the panel is a short job. A unit at the back of the house with a finished basement between it and the panel is a longer one.

Permits, and the rebate paperwork

New circuits mean an electrical permit and an inspection. Depending on your city that’s either a municipal permit or one through Technical Safety BC, which we mapped out in who pulls your electrical permit in BC.

The permit is also worth caring about because of the rebates. Heat pump incentive programs in BC have real paperwork requirements, and the money moves through documented, permitted, properly inspected work by licensed contractors. Programs and amounts change, so check the current terms at the source before counting on a figure, but the general rule holds: undocumented work is how a rebate gets denied, and the denial is almost always a paperwork problem rather than an eligibility one.

Do it in the right order, and plan for what’s next

The sequence that works is boring and it saves money. Get the equipment spec including auxiliary heat, have the panel and the load looked at, get the electrical priced, then book the install. Doing it the other way around means finding out about a service upgrade with a crew already on site.

One more thing worth doing while you’re in the panel. If a heat pump is going in this year and an EV charger is a realistic possibility in the next few, size for both now. Doing one service upgrade instead of two, and pulling the second circuit while the panel is already open, is meaningfully cheaper than coming back. We make the same point in do I need a panel upgrade to install an EV charger, and it applies with more force when the two projects land within a couple of years of each other. Our EV charger installation work runs $500 to $1,500 for the charger side when the panel is already sorted, which is a very different number than doing it cold.

We handle this across the region, and the answer often tracks the housing stock. The postwar and 70s homes through Burnaby and the older parts of Coquitlam are the ones most likely to need service work first.

The short version

The heat pump is rarely the problem. The auxiliary heat and the panel are. Get the full electrical requirement in writing, have the service checked before you commit, and if an EV charger is anywhere on the horizon, size for it once. Send us your panel photo and the equipment spec and we’ll tell you which of those you’re dealing with.