[theluketaylor]

30K would be on the higher end for air source. My install this year was 25k CDN including a lot of duct work.

40K is also on the low end for geothermal. I'm guessing you were able to trench instead of drill?

If you can afford ground source it's by far the best option in cold climates. Steady ground heat means you get the same efficiency all year round. The install can be eye-watering though.

[glxxyz]

Yes horizontal loop, 200 metre trench ~2m deep with 6 pipes at the bottom. Took 3 days for a 20 ton excavator to dig and fill in the trench. Maybe I got lucky with the installer but it wasn't eyewatering. Vertical loops do cost a lot more. Repairing the lawn with turf or professional landscaping would have cost more than the install, so I did it myself with a tractor, some spare topsoil, and a few bags of Costco grass seed.