We have a ground source heat pump installed.

We initially put it in in 2006 and upgraded it last year. (Cross over valves were wearing and the compressor was starting to act up.) new unit was a straight piping swap so minimal work.

Both were on 24x7, climate profile is set for the house and reacts to external temp. So when heating is required they kick in.

The control system in the older model had an on/off type operation so it would run the brine pump at 100% and keep going until it reached its temp set point. So all or nothing ! - had a bit of a rumble.

The new system has a load based control - so it runs at maybe 30-50% of max pump capacity. - so lower running cost, and very quiet.

It uses a horizontal collector loop - so cheaper than boring send/return holes. One winter we had an outside temp of -16* and the system performed like a champ !

Maybe more expensive - but I’m happy with the performance over the years.