Heating advice for self build in Scotland

MikeJXE

I agree with the above 3 imo GSHP is the way t go, he could cut the cost by doing the trench as he has a 360 degree machine on site. Regarding the PV array the roof is not the ideal direction or slope however the ground can be perfect with zero shade 

ComicGeek

MikeJXE said:

I agree with the above 3 imo GSHP is the way t go, he could cut the cost by doing the trench as he has a 360 degree machine on site. Regarding the PV array the roof is not the ideal direction or slope however the ground can be perfect with zero shade 

The other issue with GSHP is that the heat pump units are really expensive compared to ASHP, just due to the limited numbers sold. Parts/repairs are going to be much harder in the future for the same reason. A Vaillant flexoTHERM 5 kW ground source unit is around £5k+VAT, where the 5 kW ASHP is around £3k+VAT. 

All the investment is going into ASHPs due to the larger market share, so the GSHP technology hasn't moved forward much in the last 10 years. Quite often you can get higher efficiencies from the latest cheaper ASHPs than you can from GSHP as a result. The Vaillant GSHP above is 3.64 at 45 degrees flow temp, the Vaillant ASHP is 3.65 at the same!

The main ASHP manufacturers (Mitsubishi, Daikin etc) publish their ASHP outputs down to -20 degrees, so shouldn't be any issues with the right spec and design.  

Sometimes the PV output on non-ideal roofs is still good enough. I'm just installing some additional PV on my garage's north-east facing roof, this time of year it gets sun until about 3-4pm!

MikeJXE

ComicGeek said:

MikeJXE said:

I agree with the above 3 imo GSHP is the way t go, he could cut the cost by doing the trench as he has a 360 degree machine on site. Regarding the PV array the roof is not the ideal direction or slope however the ground can be perfect with zero shade 

The other issue with GSHP is that the heat pump units are really expensive compared to ASHP, just due to the limited numbers sold. Parts/repairs are going to be much harder in the future for the same reason. A Vaillant flexoTHERM 5 kW ground source unit is around £5k+VAT, where the 5 kW ASHP is around £3k+VAT. 

All the investment is going into ASHPs due to the larger market share, so the GSHP technology hasn't moved forward much in the last 10 years. Quite often you can get higher efficiencies from the latest cheaper ASHPs than you can from GSHP as a result. The Vaillant GSHP above is 3.64 at 45 degrees flow temp, the Vaillant ASHP is 3.65 at the same!

The main ASHP manufacturers (Mitsubishi, Daikin etc) publish their ASHP outputs down to -20 degrees, so shouldn't be any issues with the right spec and design.  

Sometimes the PV output on non-ideal roofs is still good enough. I'm just installing some additional PV on my garage's north-east facing roof, this time of year it gets sun until about 3-4pm!

Thank you for the reply

Very interesting