Do heat pumps work when it's really cold?

Yes — heat pumps do work in really cold weather, but how well they perform depends on the type of system and how cold it gets.

How they perform in the cold

Modern heat pumps (especially cold-climate models like Mitsubishi) are designed for places like Nova Scotia and can:

• Operate down to -20°C to -30°C

• Still provide heat, even in freezing temps

• Maintain good efficiency compared to electric baseboards

What changes when it gets very cold

When temperatures drop really low:

• The heat pump loses some efficiency

• It may run longer cycles to keep up

• You might rely on a backup heat source (electric heat strips or existing system)

Real-world in Nova Scotia

• Around -5°C to -15°C → works great, very efficient

• Around -15°C to -25°C → still works, but less efficient

• Below -25°C → still runs (on good units)

The key factor most people miss

A heat pump’s cold-weather performance depends heavily on:

• Proper installation (sizing, charge, airflow)

• Clean coils and filters

• Regular maintenance

A poorly installed or neglected system will struggle way sooner than it should.

Local insight

Around Halifax, we see a lot of systems underperform not because of the cold — but because they weren’t set up right or haven’t been serviced.

That’s why companies like Colgrove Air focus on:

• Proper cold-climate unit selection

• Correct installation for Nova Scotia winters

• Affordable maintenance to keep performance high year-round