The standard supply for a new house seems to be circa 18KVA single-phase. I have a client who needs to make application for a supply for a new build house at 400m2 with the only certain information being that an air source heat pump is to be used for heating. The client simply does not know what the electrical loading might be. The house is only coming out of the foundations but the DNO supply may take many months as the house is in a relatively remote rural location, thus loading details are required before the DNO will consider progressing the proposal. It is a big house, but that is what it is, just a big house. I am inclined to advise a standard supply but 3-phase as with a large AS heat pump, maybe shower, cooking and perhaps an EV or two, 18KVA wouldn't be long being gobbled up. As we move towards a higher reliance on electric as a power source for some heavy current-using equipment, it might be that 18KVA is no longer a realistic standard supply for even the smaller property.
I also think these heat requirements are far too low. Ventilation of this property of 1 air change per hour will need far more than Andy has allowed, and zero changes per hour is generally fatal for anyone with lung problems. I think a 3ph 100A supply is quite reasonable, and if it is never all used, well thats that. I see a COP of 4 is being used for the heat pump, this is too high too, At -5 to +25 it is unlikely to make 3 for an air excahnge unit (including the fans necessary to make it work properly). I love the idea of never opening a door or window, you can loose 1kWh in a few seconds on a cold day because the postman came, and it takes at least 20 minutes of the described system to get the temperature back to that required. -5 is not the English outside temperature either, it is more like -20 when it snows and the Wind gets going. This is severely underdesigned. If in upland Scotland it is criminal!
I also think these heat requirements are far too low. Ventilation of this property of 1 air change per hour will need far more than Andy has allowed, and zero changes per hour is generally fatal for anyone with lung problems. I think a 3ph 100A supply is quite reasonable, and if it is never all used, well thats that. I see a COP of 4 is being used for the heat pump, this is too high too, At -5 to +25 it is unlikely to make 3 for an air excahnge unit (including the fans necessary to make it work properly). I love the idea of never opening a door or window, you can loose 1kWh in a few seconds on a cold day because the postman came, and it takes at least 20 minutes of the described system to get the temperature back to that required. -5 is not the English outside temperature either, it is more like -20 when it snows and the Wind gets going. This is severely underdesigned. If in upland Scotland it is criminal!
