Do I need three phase for a large heat pump?

[PebbleSky]

We're redoing our large house (4,000sqft) and hoping to put in a ground source heat pump to meet the heating/hot water needs. We've had an energy consultant who has worked out our requirements and said we need three phase electricity to run the pump. Turns out it costs many tens of thousands to get 3 phase put in!

I've asked them if there's a single phase option but waiting to hear back, and I wondered if anyone else here has experience of heating a large house using a single phase heat pump?

Aiui this should mainly be covered by the supplier and you would just pay to upgrade your connection to the shared supply (recent change apparently ). Are you very remote? Who gave you the quote?

For that money you could probably do a lot to reduce the heat loss from your house, and you may not need such a big pump then. In fact another thing to check is whether the proposed unit is oversized. If you have big radiators/underfloor heating, reasonable insulation and importantly good airtightness, that will make a bit difference to the size of unit you will need.

Well ask yourself the question, is a specialist energy consultant likely to know, or a bunch of people who have never seen the house on mumsnet ?

If you don't trust the energy consultant, I would get another energy consultant to check their work.

The fact that you are going for a ground source pump and have a 4000 sq ft house means you are already in a pretty specialist area.

As for 3 phase being free, no I don't think so. And yes, it would cost a lot depending on the installation, as you might need to run cables back to the substation.

You might find two heat pumps are a better option if say you are using one for heating areas that you don't use much. But of course that means two pumps, two maintenance bills etc. A specialist consultant who has seen the problem is best placed to know.

It's Northern Powergrid. The estimate is over 65k which is ridiculous.

No I don't rate our energy consultants!