So… we’ve been living with our IVT Greenline HT+ E11 11kW ground source heat pump for another week or so now and I happy to report that it’s still performing admirably.

The outside temperature is just below 0°C and the house is nice and warm, with the new part of the house with underfloor heating at around 20°C.

The glycol based heat transfer fluid which collects heat from the ground is currently entering the heat pump at 1.3°C and after heat has been extracted from it, it is being returned to the ground loop at -1.9°C.

We currently have the hot water temperature set to 48°C but I’m going to try lowering that to 47°C in an effort to squeeze a bit more efficiency out of the system for no noticeable impact.

I’m also watching the electricity meter and compressor operating times like a hawk but so far my gut feel is that we’re using less electricity than we were over a similar period of cold weather last year.