Cost to Power Flush Central Heating – How Much Should You Pay?

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This page is all about central heating power flushing.

Central heating systems can become clogged with rust, sludge and scale from the water that’s pumped around the pipework.

Common symptoms and problems are:

  • Cold spots on radiators
  • Noises coming from the system
  • Slow warm-up times
  • Inefficiency
  • Wear and tear on the pump and other parts

Our Guide to Power Flushing Prices

In 2014 and again in 2018 we sent out quote requests to central heating engineers and specialist firms.

We asked each of them to provide us with a price to power flush a central heating system in a 3-bed house.

Below you’ll see the results of our research, we think this information is very insightful and should give you a very good idea of how much central heating power flushing will cost.

The last time we updated our prices was on the

You can arrange a custom quote for yourself by filling out the form on this page.

How Many Firms Responded to Our Request?

We sent out a total of 29 requests but only 23 firms responded and provided us with prices for power flushing.

The lowest price we were given was £225 while the highest was an eye-watering £700.

What You Get For Your Money

Power flushing is a technique used to clear out sludge from central heating system pipes, radiators, coils and heat exchangers.

These are areas where scale and corrosion are most likely to collect and cause problems.

Blocked central heating system

This is how a power flush is done (we based this list upon the written quotes provided to us):

  1. Note the temperature of each radiator (so we know which ones are clogged)
  2. Record TRV settings for each radiator
  3. Take a water sample
  4. Open all valves and remove the TRVs
  5. Bridge any valves or equipment that may prevent a reverse flow, for example, a pump
  6. Isolate the boiler
  7. Connect the power flushing unit
  8. Power flush the system and loosen any stubborn particles from the radiators with a vibrating tool
  9. Take the temperature of individual rads and compare to original radiators
  10. Test water the water for purity
  11. Add a rust inhibitor
  12. Refit the radiator valves and the apply original settings

Cost to Power Flush – Updated Prices For 2018

Below you can see the results of our research into power flushing prices.

As we sourced prices from both small and large firms from various locations around the UK, we have tried to display the average prices by business size and locale.

The average price we received was around £450. This is slightly less than the average price we sourced in 2014 which was £475.

LocationSmall Business /TraderLarger Business (5+ employees)
London Area£425.00£600.00
South, SW and Midlands£425.00£525.00
Outer Region and North£350.00£500.00
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We think our research is insightful but if you would like to arrange a fixed written quote for a pro to power flush your heating system, just tap the button below.

  • Send in details about your central heating system
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How Long Does This Project Take?

When sourcing prices, we asked our chosen firms how long they thought it would take to power flush our central heating system.

Obviously, the time it takes will depend on how many radiators there are and how clogged the system is, no two houses are the same.

We were told that for a typical three-bed house, it would take anything from 5 to 7 hours.

Frequently Asked Questions

We sourced the following answers from the information packs given to us and from the websites of several of the firms we contacted.

Q: Will the radiators need to be removed?

A: In some cases, compacted sludge can only be removed by removing the rads and manually cleaning them with a powered pressure washer/hose but most of the radiators shouldn’t need to be removed.

Q: Instead of having the system flushed can I not just install a magnetic filter?

A: Sludge and rust trapped inside the radiators will not circulate with the water, so won’t be captured by a magnetic filter. These filters work well as a preventative solution but won’t remove any existing sludge.

Q: I have had my rads repeatedly flushed, but they keep blocking up with sludge, why is this?

A: This might be because your heating system is allowing air into the pipework, this will accelerate the corrosion of the pipes and radiators. We suggest you have your heating system checked by a qualified engineer before you flush the system again.

Q: How often should I have the system power flushed

A: Firms suggest every ten years but most consumers wait much longer.

Q: Can all types of central heating systems be flushed?

A: Yes, all types of water-based central heating systems can be flushed.

Q: Are TRVs (radiator valves) an issue?

A: No, the pins can get stuck as a result of the sludge, but this is easily fixed and these valves are also easy to replace.

Q: I have received a quote for £150, is this a fair price/cost?

A: For this price, we would not expect a complete and thorough power flush, although the water may run clear after a power flush it may be because the water is flowing over compacted sludge.

Q: Should I have the central heating system drained and refilled every year?

A: No. This will only add oxygen and other impurities to the water; this will accelerate the corrosion. You’ll also need to top up the inhibitor which will just add to the cost.

Q: What is the sludge made from?

A: It is mostly rust that corrodes from the metal pipes and radiators, but also contains contaminants and scale from the water.

Compare Quotes For Your Power Flushing Project Today

As with any home improvement project, we always recommend getting at least three quotes for comparison.

With that in mind, we recently teamed up with Rated People.

They can supply you with up to three written quotes from local tradespeople, you can read reviews created by recent customers and take your time making a decision.

Tap the button below and fill out the form. Rated People is a free and popular service:

  • Fill out the form
  • Get your quotes in a timely manner
  • Compare ratings and reviews created by past customers
  • Leave your own feedback and rating when the power flushing job is complete
Click Here to Get Your Free Plumbing Quote

Not ready to get quotes? See all of our cost guides here

10 Responses to “Cost to Power Flush Central Heating – How Much Should You Pay?”

  1. Michael QuinlanApril 20, 2016 at 5:06 pm #

    When was this written?

    • QuotationCheck AdminApril 23, 2016 at 5:41 pm #

      Hi, this page was last updated November 2014. Thanks, Admin.

  2. D P ColeAugust 31, 2016 at 10:04 pm #

    You do not warn that with the removal of sludge some radiators may leak. Then presumably they wpuld require replacing.
    In this area HA6 would you give the names of specialised Power Flush Engineers. ***************.com

    I have some 20+ radiators!!

  3. johnOctober 5, 2016 at 11:08 am #

    My system is under mains pressure so I do not have a tank in the roof, does this make any difference to the price

  4. Rob ScottDecember 14, 2016 at 4:36 pm #

    I have been quoted £1000-£1100 to flush the system in my four bed house and replace the four radiators upstairs with more efficient ones, does this seem reasonable?

  5. Ron AndersonMarch 21, 2017 at 10:35 am #

    My brother just had his central heating system power flushed by Chas Stewart Plumbing & Heating Ltd and was charged £1250 for the job. 7 radiator system. Rip off merchants of the highest order. Should be featured on rogue traders. Disgusting.

  6. Mr SpinettoFebruary 2, 2018 at 3:21 pm #

    Quote for a Power Flush for a 3 bedroom semi with a combi boiler having 8 radiators of various sizes.
    Location: Stafford ST17

  7. MarcusNovember 4, 2018 at 7:44 am #

    My dad has been told that a 12 radiator set up would take 15 hours and 30mins to complete the flushing and they are charging a couple of grand for it, is this legit?

  8. Gina MooreFebruary 9, 2019 at 11:20 pm #

    We have been quoted £685 today by British Gas for a 3 bedroomed semi with 8 radiators

    • Hannah DavisonMarch 9, 2019 at 11:14 am #

      Hi Gina,
      *First off my husband is a gas engineer with 28 years experience, so i have some knowledge of what im talking about.*
      In my opinion you’d be far better off getting a local firm to do it for you.
      Probably pay somewhere in the region off £450 give or take. It should take them 4 hrs upwards depending on issues. Be warned though if you have any pin holes in pupework or radiators, when the chemical does it’s magic this may disturb the magnatite and cause small leaks (only in very rare cases)
      BG are always a fair bit more expensive as they have such large overheads and shareholders. Just for the record, most of the time they sub the work out to small firms and pay them a fraction of what they charge you…
      As I said at the beginning I know where I’d prefer to spend my money.

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