Are you thinking about having your central heating system cleaned? What are the benefits of this procedure and how much will it cost?
This page was created by Paul, a central heating engineer with over 20 years experience.
Don’t forget: this is just one of many dozens of price guides we have created. Join the many thousands of other people who have saved money by exploring our full price list here.
Continue reading this page and you will discover:
- common problems that can be solved by powerflushing
- the best time to have this work carried out
- a price guide with some examples for typical houses
- a step-by-step guide to powerflushing so you can see what work is done
- a link so you can arrange a quote for your property
Before You Proceed
Before we reveal the cost to powerflush, we would be grateful if you could answer the question below.
This question is entirely optional and you can, of course, skip it if you wish.
We are conducting research into how much homeowners think certain home improvement projects should cost.
We may publish the results of this poll at a later date.
Why Powerflush – What Are The Benefits?
Powerflushing can solve many common issues:
Inefficient radiators – blockages in radiators can result in cold spots and general inefficiency of the system. Flushing out those blockages can and will reduce heating bills.
Stress on the boiler – an inefficient blocked system requires more time to warm up, putting extra stress on the boiler and your wallet.
Stress on the pump – if the system is blocked, the pump could be working extra hard just to keep the water moving, thus reducing the life expectancy of the pump. A new pump isn’t cheap and this extra cost could be avoided by removing the sludge in the system by powerflushing.
Noises – a blocked system can result in knocks, vibrations and other sounds as the pump struggles to push the water around the system.
Powerflushing ensures you are still covered by your home insurance – some insurers, including “Home Care” or similar policies are now refusing to pay out if the homeowner has knowingly refused to maintain the central heating system and this has led to a failure of the system.
How Does it Work?
The 2-part video below explains how the powerflushing system is used to clean out radiators and pipework:
Below is a typical works schedule, most powerflushing companies will carry out most of the items listed here.
While this list isn’t exhaustive, it covers the primary steps:
Can This Work Be Done “DIY”?
Powerflushing requires expensive equipment and chemicals so is usually done by specialist companies or plumbers with experience of central heating systems.
It is possible to remove the radiators in a house and give them a flush through.
While this isn’t nearly as effective as a professional clean, it can remove a lot of debris in the radiators and solve some issues such as cold spots.
See the video below:
Powerflush Cost Guide:
Below is our cost guide for powerflushing a heating system:
|6 Rads (2bed house)||£400|
|8 Rads (3bed house)||£475|
|10 Rads (4bed house)||£525|
The prices above assume you go with a local company. The big nationals always charge more and British Gas have been known to charge over £700 for this type of work.
How Long Does it Take to Complete?
This depends on how clogged the system is. Some heavily blocked systems on a typical 3-bed house could take all day to unblock.
But for an average system of 8 radiators in a 3-bed house, expect the work to take around 5 hours.
If you are having a filter fitted, then add an extra half hour to the project.
What if Powerflushing Doesn’t Work?
Powerflushing doesn’t always work and if the system is badly fouled it probably won’t.
The next step would be to try a powder flush.
This is a much more abrasive type of flush but works exceptionally well:
More information can be found on the Power Flushing Association website.
Another option is to fit a magnetic filter after the system has been powerflushed, this will collect any rust that forms.
As the sludge is a system is made from 80% + rust, this should protect your system from clogging again.
Prices vary but according to the Emergency Plumber website, you’re looking at around £300.
The British Gas Conundrum
As some of you will be aware, British Gas and several other well-known firms provide insurance for central heating systems.
They also offer, amongst other things, powerflushing services.
However, in recent years, many of these firms have refused to renew the insurance or to honour a claim if the system hasn’t been powerflushed recently.
Queue the upsell.
Here is a claim from a British Gas customer from way back in 2009:
Having been refused British Gas cover on CH system due to excessive iron oxide sludge, we were told £680 to get a powerflush by BG which we got told was a lifetime guaranteed one.
So, one could argue that British Gas are using their insurance policies to encourage customers to have costly maintenance work such as powerflushing done.
The more pessimistic of you may also choose to bet your last penny that they will try and flog you an overpriced filter too.
While there’s nothing illegal with this tactic, it does highlight issues with impartiality when they are an installer, repairer and insurer all in one.
Given that British Gas and many of the other big energy firms charge top rates for powerflushing, we suggest contacting a local business that can do the work at a more reasonable price.
Provided you get a letter or certificate of completion, you should be able to renew your insurance policies.
Beware of the Upsell
Rumours have been circulating for years that some of the big energy firms are paying their engineers a commission to recommend a powerflush.
While they have consistently denied this, British Gas have admitted to paying extra for what they describe as “earning time bonuses” for “giving best advice”.
In essence, they earn more money for recommending customers replace boilers or have the system powerflushed.
Jeff Howell, who writes for the Telegraph has been warning about this potential conflict of interests and upsell for years.
What is the Best Time of Year to Powerflush a System?
Some trades are very seasonal and the demand for their services fluctuates throughout the year.
A good example is landscape gardeners who often experience quiet spells during the winter months. As a result, they often reduce their prices, just to keep things ticking over until the busier summer months.
Central heating engineers and hot water plumbers also experience spikes in demand, usually during cold snaps of weather when boilers breakdown and need repairs.
Unlike roofers and gardeners though, we have found that powerflushing prices appear to stay the same, regardless of the time of year.
So while you may need to wait a little longer for a powerflushing firm to do the work in the winter, the price will most likely be the same as during the summer.
VAT – Did You Know That Not Everyone Pays It?
The VAT rate is currently 20% and some smaller firms that operate below the VAT threshold do not need to charge this.
This means you could make a significant saving.
Get a Quote
This page was created by our website contributor Paul, who has 20 years experience of central heating systems.
To get a quote for your heating system, hit the link below to see how we can help you:
The only way to know is to have the system tested by a professional. However, there is some mis-selling within the industry, with many companies carrying out the work when it wasn't needed.
We recommend reading this article from a heating engineer.
We are a home improvement cost guide website.
We have many years experience in this sector so we decided to put our knowledge on the web.
If you are researching prices, use our cost guides as starting point.
If your system is faulty and is drawing in air, then this can significantly increase the amount of rust produced and the system may need to be flushed again in 8-10 years.
Assuming you have a healthy system, then a powerflush every 15 years would be a good idea.
You should have the system flushed just before installing a new boiler, if you don't, you may find that your guarantee is invalidated.
Otherwise every 10-15 years depending on old your system is and how much use it gets.