Geothermal vs. Air Source Heat Pump

Geothermal is better known, but an air source heat pump is what your house needs. Find out more.

Geothermal is better known, but an air source heat pump is what your house needs. Find out more.

Choosing geothermal or heat pump

We find that most folks have heard of geothermal or ground source heating systems, and many have good associations with them. But they aren’t the answer for any single dwelling, whether conventional or passive.

Canada and many of our neighbours globally are moving to more sustainable home building and heating technologies. Net zero is the watch word we’re all hearing more and more.

If you own a conventionally built home and your furnace is nearing the end of its life (typically around the fifteen year mark), heat pumps have become the main replacement option.

We want to be sure that anyone researching this option understands that air source heat pumps are the answer, and not ground source. We’ll explain more — read on.

Click to learn more about our net zero bungalow in Ottawa, Canada.
EkoBuilt’s passive (and net zero) model home makes use of the technology we recommend for most of our homes – an air source heat pump in combination with an ERV or fresh air machine.

Heating for scale

Don’t get us wrong, geothermal heating systems are capable of pulling huge amounts of heat energy from the ground, proportionally much more than an air source heat pump.

In very broad terms, a ground source heat pump can pull roughly ten times the energy compared to a similarly sized air source heat pump, but the system required to do this will also cost roughly ten times that of an air source heat pump system.

It’s simply a question of scale. A ground source heating system is fantastically well suited to large commercial applications and to large residential applications, such as a townhome or condo development.

In the case of a community of a dozen town homes, it would be more efficient to have a single geothermal system as compared to a dedicated air source heat pump for each individual unit.

Click to learn about EkoBuilt's multi-unit house plans.
A designed community of a dozen or so townhomes would be a great candidate for a single geothermal system. If you were retrofitting a single unit, an air source heat pump system would be a better, far more affordable option.

Running the numbers

The other factor here is that air source heat pumps have become more powerful and more robust in recent years.

There are now several options on the market that are suitable for cold climates, like our own home patch of Ottawa, Canada. These units have frost protection and reheating cycles built into them.

A passive home, which requires only a fraction of the heating / cooling energy of a conventional home, would typically require a 10,000 BTU heat pump.

Conventionally built homes will more typically require systems in the 60,000 to 100,000 BTU range. In terms of purchase / installation cost, the heat pump system for a conventional home will cost up to three times more than the ones needed for our passive homes. In terms of running cost, the savings keep adding up!

A fully passive home like our 1,600 sq ft, four bedroom model home in Ottawa, Canada, needs only a small air source heat pump to handle heating for the entire home.

Go passive to go net zero

It’s a simple equation. If you’re looking to cut your energy requirement, a passive home is the strongest option. It’s the most affordable and quickest way to reach net zero.

Low energy retrofits are also a responsible approach for owners of older homes in mature neighbourhoods, but be aware of the cost. Retrofitting will cost more.

If you’re looking to start your own passive house journey anywhere in Canada or the US, give us a shout!

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