How much does a power flush cost in the UK?
A power flush costs £300 to £1,000 in the UK, typically around £500 for the system. What moves the price most is number of radiators, so a simpler job sits near the bottom of that range and a larger or higher-spec one near the top. Prices reviewed June 2026.
A power flush clears sludge and debris from a central heating system. It is priced mainly by how many radiators you have, with a magnetic filter often added at the same time.
Power flush cost calculator
Use the calculator to price your power flush in 2026. Adjust the options and area for a UK cost range. Nothing is sent anywhere.
Power flush cost breakdown
Typical power flush costs, by option:
| System size | Typical UK cost |
|---|---|
| Small system (up to 6 radiators) | £300 to £500 |
| Standard (7 to 10 radiators) | £450 to £700 |
| Large (10+ radiators) | £600 to £1,000 |
| + Magnetic filter fitted | add £100 to £250 |
What's included in the price?
Typical power flush prices include:
- Flushing the whole system with a pump and chemicals
- Cleaning each radiator
- Adding inhibitor to protect the system
- Checking the system runs clear
What changes the price?
The things that move power flush prices most:
Number of radiators
How sludged the system is
Access to all the radiators
Whether a magnetic filter is fitted at the same time
Does where you live change the cost?
In London, a power flush typically costs around £650 for the system, about 30% above the UK average of £500. In the North, Scotland and Wales the guide figure is nearer £460.
| Region | From | Typical | Up to |
|---|---|---|---|
| Midlands / East (UK average) | £300 | £500 | £1,000 |
| London | £390 | £650 | £1,300 |
| South East / South West | £350 | £580 | £1,200 |
| North / Scotland / Wales | £280 | £460 | £920 |
Guide prices for the system, scaled with the same regional multipliers as the calculator. Not quotes.
Power flush cost in major UK cities
| City | From | Typical | Up to |
|---|---|---|---|
| Belfast | £260 | £430 | £850 |
| Birmingham | £290 | £490 | £980 |
| Bristol | £330 | £550 | £1,100 |
| Cardiff | £280 | £470 | £940 |
| Edinburgh | £290 | £490 | £980 |
| Glasgow | £270 | £450 | £900 |
| Leeds | £280 | £470 | £930 |
| Liverpool | £280 | £460 | £920 |
| London | £390 | £650 | £1,300 |
| Manchester | £290 | £480 | £960 |
| Newcastle | £270 | £450 | £900 |
| Sheffield | £280 | £460 | £920 |
City guide estimates, scaled by local labour costs. Indicative averages for power flush, not quotes.
London and the South East run above the national figures on labour.
Common questions
How much does a power flush cost?
A power flush costs roughly £300 to £1,000 in the UK, typically around £500. A small system of up to six radiators is £300 to £500, a standard seven to ten radiator system £450 to £700, and a large system with more than ten radiators £600 to £1,000. Fitting a magnetic filter at the same time adds £100 to £250 and is well worth it.
What are the signs you need a power flush?
The usual signs are radiators that are cold at the bottom but warm at the top, patches that never heat up, a noisy boiler or pump, and dirty black water when you bleed a radiator. These point to sludge building up in the system. A power flush clears it, restores even heating, and protects the boiler, which is why installers often insist on one before fitting a new boiler.
Is a power flush worth the money?
If the system is genuinely sludged, yes: for £300 to £1,000 it restores heat, cuts running costs and can add years to the boiler and pump. It is also often a condition of a new boiler's warranty. Where it is not worth it is on a clean, well-inhibited system with no symptoms, so ask the engineer to show you the evidence rather than flushing as a default.
Do you need access to all radiators for a power flush?
Yes. The engineer connects the flushing pump and works through the system radiator by radiator, so every radiator needs to be reachable and its valves operable. Furniture may need moving and seized valves can add time or cost. If a radiator cannot be reached or isolated, that part of the system will not flush properly.
Is a chemical flush cheaper than a power flush?
Yes, a simple chemical clean or a mains flush is cheaper at around £150 to £300, but it is less thorough than a full power flush with a pump. For a lightly dirty system it may be enough; for a properly sludged one a power flush shifts far more. A good engineer will recommend the right level rather than upselling, so ask which your system actually needs.
Can I power flush my heating system myself?
You can hire a flushing machine, but it is fiddly and most people are better paying the £300 to £1,000 for a proper job. You need to move the pump around every radiator, handle the chemicals and refill and rebalance the system afterwards. If your boiler is under warranty, doing it wrong can affect the cover, so a heating engineer is the safer route.
These are independent guide prices based on typical UK jobs in 2026. Your actual cost depends on your property, spec, access and where you live. Always get at least three written quotes before committing.