£9,700 to £14,300, then £7,500 comes off.

A typical 8 kW install in a three-bedroom house. The line that moves most is the radiators — which is another way of saying the line that moves most is your flow temperature.

Heat pump, 8 kW monobloc£6,200 – £7,400R290 propane refrigerant, 60 °C capable, 5-year parts and labour

Cylinder, 210 l unvented£1,100 – £1,500Most homes need one. If you have no space for it, say so now rather than at survey

Radiator changes£180 – £320 eachTypically 4 to 9 of them. This is the line that varies most between houses

Pipework, controls, commissioning£1,800 – £2,600Including the weather compensation controls that make the whole thing work

Scaffold, electrics, making good£600 – £1,400A new consumer unit way is common. So is a small amount of plastering

Typical total

£11,800

8 kW, 6 radiators changed, 210 l cylinder

Grant

−£7,500

Applied to the invoice by us

You pay

£4,300

Half on start, half on commissioning

Running cost, honestly

Against gas it is close. Against oil it is not.

At a 45 °C flow temperature and 2026 prices, a heat pump and a modern gas boiler cost within a few pounds a month of each other in most houses. Get to 40 °C and the heat pump wins clearly. Stay at 55 °C and it loses. That is the whole story, and anybody promising you a halved bill has skipped it.

Questions

Will it work with my existing radiators?

Some of them, usually. A radiator sized for 70 °C water gives out roughly half as much heat at 45 °C, so the ones in your coldest rooms get bigger. The survey tells you exactly which — typically a quarter to two-thirds of them, depending on the house.

Is it cheaper to run than gas?

At 45 °C flow and 2026 prices, roughly the same. At 35 °C it is meaningfully cheaper. At 55 °C it is dearer. This is why the flow temperature slider on this site exists rather than a claim.

How loud is it really?

About 42 dB at a metre, which is a fridge. It is not silent, it runs at night in cold weather, and if your neighbour's bedroom window is three metres from the best position we will find a worse position that keeps the peace.

Do I need a hot water cylinder?

Almost always, and it needs about 60 × 60 cm of floor and 1.8 m of height. If you have a combi and no airing cupboard, this is the constraint that decides the job, not the heat pump itself.

What if it breaks?

Five years parts and labour on the unit, two on our workmanship, and we hold the common spares. We are twenty minutes from most of Bristol; that is the actual reason to use a local installer rather than a national one.