How a heat pump gets installed, step by step

What happens before heat pump installation day?

Good installs are decided on paper, and the installation process starts well before anyone arrives with tools. The contractor visits the house, looks at the existing heating, ducts, insulation, windows and electrical panel, and measures what the system must deliver on the coldest design day. That is the heat-loss calculation, explained in our guide to heat pump load calculations. It sets the size, and a guess based on the old furnace usually sets the wrong one, which is why sizing for cold climates deserves attention.

Next come the quote and the permit. Check that the quote names the equipment and the work involved, using the tips in how to compare heat pump quotes. Most municipalities require electrical and sometimes mechanical permits, and a reliable installer will arrange them. If you are still choosing a company, start with how to choose an HVAC contractor.

Where does the outdoor unit go?

The outdoor unit of an air-source heat pump needs clear airflow, a firm base and a location away from bedroom windows and the neighbour's fence line. In Canada it also needs to sit above the expected snow depth, so installers often use a raised pad or wall brackets, and keep the unit clear of roof drip lines and drifting snow. Defrost water must drain away without freezing on a walkway, a point covered in defrost cycles and noise.

The indoor side depends on the system. A ducted system connects to an air handler or replaces the furnace and uses the existing ductwork, while a ductless system puts wall or ceiling units in chosen rooms. Either way, the two ends are joined by copper refrigerant lines, a condensate drain and control wiring, run through a small opening in the wall.

What happens on heat pump installation day?

1. Mounting. The crew sets the outdoor pad or brackets and mounts the indoor unit or air handler.
2. Connections. They run refrigerant lines, drain and wiring, and an electrician connects power and a disconnect switch. Some homes need a panel upgrade or a new breaker, which should show up in the quote.
3. Leak test and vacuum. The lines are pressure-tested and pulled into a vacuum to remove air and moisture before refrigerant is released.
4. Commissioning. The installer sets refrigerant charge, checks airflow and temperatures, programs the controls and sets how any backup heat takes over.
5. Inspection and handover. You get a walk-through, the manuals and warranty registration details.

If a furnace is coming out at the same time, the day looks like the one in furnace installation day, with extra refrigerant steps.

How should you prepare your home?

Clear a path to the indoor and outdoor locations and move anything fragile away from the work area. Plan for power to be off for a time. Pets and small children are better elsewhere, because doors will stay open. Agree on the unit locations and the route of the lines before the day, so that nobody drills a hole in the wrong wall.

Ask where the thermostat or controller will go and how the backup heat is set. In an older house, ducts, insulation and air leaks may need work for the system to perform; see heat pump installation in older homes.

What should you check after the install?

Run the system through a few days of normal use and confirm that each room reaches the set temperature, the unit is not unusually noisy and the outdoor coil defrosts and drains. Keep the commissioning report and the permit sign-off. Our maintenance checklist shows what to check every month or season, and a call-back to the installer in the first winter is normal if something is off.

Efficiency and energy efficiency claims on the quote should match the installed system. Costs depend on the system type, the electrical and ductwork needs and the region. The heat pump cost guide lists the drivers without quoting a single national price.

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