Ground Source vs. Air Source Heat Pumps: Which One is Better for Cold Climates?

When it comes to heating your home in freezing temperatures, cold weather heat pumps have become a game-changer. But should you go with a ground source heat pump (GSHP) or an air source heat pump (ASHP)? Both have their pros, but which one performs best in subzero conditions? Let’s get into it.

The Basics

A ground source heat pump (GSHP), also known as a geothermal heat pump, pulls heat from beneath the earth’s surface, where the temperature is stable year-round. It uses underground pipes filled with a heat transfer fluid to collect warmth and distribute it inside your home.

An air source heat pump (ASHP) absorbs heat from the outside air—even in subzero conditions—using a refrigerant cycle. It then compresses the refrigerant to increase its temperature and delivers warmth inside.

Both use the same refrigeration cycle, but different heat sources—one from the ground, the other from the air. So, which is better for cold weather heat pumps?

 

Cold Climates

Ground source heat pumps provide steady, reliable heating because the temperature underground is constant, around 10-15°C, even in winter. They aren’t affected by extreme cold, so great for cold regions.

Air source heat pumps, especially those designed for arctic climates, can extract heat from air as cold as -30 (-22f). But their efficiency drops as temperatures plummet, so they might need to work harder or use backup heating in extreme winter conditions.

For extreme cold, GSHPs are the way to go.

Energy Efficiency and Costs

GSHPs are highly efficient, often with a Coefficient of Performance (COP) of 4 or more, meaning 4 units of heat for every unit of electricity used. However, installation costs are high due to the underground piping.

ASHPs are cheaper and easier to install but less efficient in extreme cold, need more electricity to work and COP can drop to 2 or 3 in harsh winter conditions, so higher energy bills compared to GSHPs.

For efficiency, GSHPs are the winner, but for affordability, ASHPs win.

 

Installation and Space Requirements

GSHPs require excavation, either horizontal trenches which need a big yard or vertical boreholes which need drilling but less space. Installation can be costly and disruptive.

ASHPs are compact, easy to install and no underground piping—just an outdoor unit. Great for homes with limited outdoor space.

For easy installation, ASHPs are the way to go.

Which One Should You Choose?

If you live in an extremely cold climate and want long-term efficiency, a ground source heat pump is the best choice if you can afford the installation cost.

If you’re looking for a more affordable, easy-to-install option, an air source heat pump can still work well, especially with modern cold-climate models.

Both cold weather heat pumps offer energy-efficient, eco-friendly heating, making them excellent alternatives to traditional fossil fuel systems.