Heat pump quotes

This is where the decision is actually made, and it is a bigger question than the price.

A heat pump suits a house with reasonably good insulation, manageable heat loss, and radiators able to keep rooms warm at lower water temperatures than a boiler runs at. You also need room for the outdoor unit, a hot water cylinder and the pipework between them. The house does not have to be perfect, but it does have to stay comfortable without the high flow temperatures a gas boiler relies on.

If that does not describe your house, a heat pump will not perform the way it is sold to you. The answer then is that it is not suitable yet, and the money is better spent on insulation and radiators first.

The heat pump cost calculator shows the figure after the grant. What moves it is the size of unit your house needs, whether radiators are being changed, and where the cylinder is going.

Grants are available and the calculator already takes them into account. In England and Wales that is the Boiler Upgrade Scheme, with a higher grant for properties off the mains gas grid replacing oil or LPG.

In Scotland it is the Home Energy Scotland Grant and Loan, which covers air, ground and water source heat pumps. There is an uplift for rural and island properties, and an optional interest-free loan on top to cover what the grant does not. The calculator applies the standard Scottish grant, because it has no way of knowing whether your address qualifies for the rural uplift, so check the scheme directly if you think it might.

Eligibility and amounts change. Treat the figure as current at the date shown on the page, and check before you commit.

Ask for a heat loss calculation for your house rather than a rule of thumb. Ask which radiators need changing and why. Ask what flow temperature the system is designed around. Ask where the outdoor unit goes and how loud it is. Ask who applies for the grant.

A quote with no heat loss calculation behind it. Anyone who says your existing radiators will be fine without having worked it out. Promises about running costs not tied to how you actually heat your house. Pressure created by a grant deadline.