Heat pump wiring

Electrical installation for air-source and ductless heat pumps in Edmonton: load calculations, dedicated circuits, disconnects, backup heat and thermostat wiring.

Heat pumps in a cold climate

Cold-climate heat pumps can keep extracting heat from outdoor air well below freezing, and they also cool in summer. In Edmonton they are usually installed alongside a backup heat source for the coldest nights: electric heat strips in the air handler, an existing gas furnace in a dual-fuel setup, or baseboards.

How the system is wired and controlled decides how much the heat pump does versus the backup, and that is what drives your bills. Good controls let the heat pump do as much of the work as it can before backup heat steps in.

Many Edmonton homeowners are moving to heat pumps when an old furnace or air conditioner needs replacing. Planning the electrical side at the same time as the equipment choice avoids surprises on install day.

The electrical work

A heat pump needs a dedicated circuit for the outdoor unit, sized from its nameplate, with a disconnect near the unit. A ducted system also needs a circuit for the air handler, and electric backup heat can need a large circuit of its own. Ductless mini-splits are fed through the outdoor unit, with interconnect wiring to each indoor head.

The outdoor unit should sit on a stand or wall bracket high enough to stay above snow and let defrost water drain. We route the circuit and disconnect so they are not buried by snow or hit by a snowblower, and seal every wall penetration.

Will my panel handle it?

This is the most common question. A heat pump alone often fits a 100 A service, but electric backup heat is a big load. Combine that with an electric range, dryer and an EV charger, and many homes run out of room.

A load calculation tells us what fits. Options include dual-fuel, smaller backup heat with load management, or a service upgrade. We explain each so you can decide with your HVAC contractor.

Controls and thermostats

Heat pumps need thermostats and wiring that match the equipment: staging, reversing valve control, backup heat lockouts and outdoor sensors. Many systems use proprietary communicating controls. We run the right cable during rough-in, often with spare conductors so future changes do not mean a new cable.

For dual-fuel systems, the controls decide when to switch from the heat pump to the furnace. That switchover temperature affects both comfort and cost, and your HVAC contractor sets it. Our job is to make sure the wiring supports the control strategy they choose.

Commercial heat pumps and variable refrigerant flow systems add more circuits and control networks, often with many indoor units. We coordinate closely with the mechanical design so every unit has power and communication cabling where it needs it.

What drives cost

We do not post prices. Cost depends on the size of the heat pump and backup heat, distance from the panel to the outdoor unit and air handler, panel space and capacity, the number of ductless heads, and whether a service upgrade is needed. Electrical work is usually a modest share of a heat pump project, but skipping the load calculation can turn it into a large one.

Questions we hear