Are Magnetic Filters Worth It? How Do They Work?



Magnetic filters are a common sight on most boiler installations nowadays. This post will answer all your questions. Are magnetic filters worth it? How do they work? Which magnetic filters are best? And, how much do they cost?

What are magnetic filters?

Magnetic filters are small cylindrical units, installed on the return pipe on a boiler. Magnetic filters help protect boilers from sludge and sediment. This can help add years onto the life of a boiler. According to Adey, sludge costs the nation over £700m per year in repair bills. Also, manufacturer research found that 87% of all call outs are to systems with poor water quality.

Why do we need magnetic filters?

Due to the materials, they’re made from, central heating systems deteriorate over time. Water in the system reacts with the steel in the radiators. This reaction causes sludge to form, a black oil-like substance.

Sludge can clog up pipes, radiators and parts inside the boiler. It can also make radiators rust, and eventually develop holes.

Furthermore, sludge can drastically reduce the efficiency of a system. Sludge build-up in radiators stops them from heating up properly. Plus the restriction caused by the build-up puts added pressure on the pump.

Eventually, when left untreated, pipework can become blocked. Leaving sections of the heating system unable to work. Plus if any sludge develops in the boiler it will cause the boiler to stop working completely. Pumps can get stuck, heat exchangers get blocked completely and sensors can get clogged up and stop working. Magnetic filters can help prevent this from happening.

How do magnetic filters work?

As their name implies, magnetic filters use magnets to clear the system. Created from the steel deteriorating, the sludge is highly magnetic. All magnetic filters have powerful magnets inside which collect the magnetic steel and iron particles. This stops them entering the boiler where they will do the most damage. And, gradually will help clear the system.

Should I get a magnetic filter?

Most gas engineers usually install magnetic filters as standard when installing a new boiler. They are a cheap and cost-effective way to prolong the life of a boiler and protect a heating system.

Manufacturers encourage installers to install filters to protect the boiler. Some boiler manufacturers offer extended warranties when their boilers are installed with their own brand filter.

Please note magnetic filters cannot be expected to clean the entire system. Also, to ensure as much sludge is removed as possible, the system should be flushed thoroughly.

If a system has a lot of sludge, the magnetic filter will reach its full capacity very quickly. And won’t be able to do its job.


When a new boiler is installed, inhibitor should be added. Inhibitor helps prevent corrosion from developing in the system. Sometimes, manufacturers will test for inhibitor level. If the inhibitor level isn’t adequate it may invalidate the warranty. The inhibitor can help prevent corrosion but isn’t a replacement for a filter. Inhibitor always works best in conjunction with a magnetic filter.

Can I add a magnetic filter to an existing system?

Provided the pipework is easily accessible, installing a filter should be a small job.

It would take a good engineer no more than a few hours to install and cost around £120 plus the cost of the filter.

Which magnetic filter is best?

Here are our five favourite magnetic filters and a short review of each one. Are magnetic filters worth it? These ones definitely are!

1. Adey Magnaclean Professional 2

Adey was one of the first companies to develop the idea behind magnetic filters. The Magnaclean Professional 2 was the replacement for their initial product, the Magnaclean Professional.

The Professional 2 is an inline filter and is extremely easy to install. It has a twin flow feature, meaning it the water can flow through either way. Multiple installation options are available due to the 360 • rotational valves.

The Professional 2 is a practical size, meaning it can fit in a variety of spaces. The valves are easily shut off with the tool provided.

Adey also makes a micro version for smaller houses with fewer radiators.

Adey Magnaclean Pro 2 System Filter

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2. Fernox Omega Filter Silver

Fernox is a leading company in developing products that help clean and protect your heating system.

Made from nickel-plated brass this filter feels extremely solid and durable. It comes with isolating valves, making cleaning very easy and can be fitted in any orientation. It has a very powerful magnet and particle separation technology.

TF1 Omega Filter by Fernox

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3. Fernox TF1 Central Heating Magnetic Filter 

The TF1 has been around for many years now and is a reliable filter. Easy to clean and isolate, t does its job well and. Due to its adjustable body, the TF1 can be installed on vertical or horizontal pipework.

But it’s awkward size and shape mean it can be difficult to install in tight spaces. Also, the location of the nuts behind the filter can make it difficult to tighten. On occasion they can leak from the lid, requiring a new seal.

Fernox tf1 filter

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4. Boilermag Domestic Heating System Filter 

A solid filter, the Boilermag will help protect your boiler from sludge. Its inline connection makes it easy to fit, but like the Fernox TF1 its awkward shape can make it impractical to install in smaller spaces. Cleaning the Boilermag isn’t as easy at the other filters.

With no proper drain point underneath, removing the nut can get messy. Also, the collection bowl can be awkward to reconnect after cleaning.

are magnetic filters worth it

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5. Altecnic Dirtmag IQ Magnetic Filter Air and Dirt Separator

A cheap but effective option. The Dirtmag IQ is easy to install with its inline connection and is relatively compact. Perfect for fitting in smaller spaces.

The magnets are located on the outside, meaning you don’t have to unscrew the lid to clean. The Dirtmag IQ also possess a dirt separator to help pull out non-magnetic particles from the system.  The lack of isolating valves can make cleaning the Dirtmag a bit more difficult.

Altecnic DirtMag IQ Prime 22mm Magnetic Dirt Separator

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Summary: Are magnetic filters worth it?

I think we have shown that magnetic filters are a must-have for any central heating system. A magnetic filter could save you hundreds of pounds over the life of your boiler. Cheap and easy to install, the question is why wouldn’t you have a magnetic filter?

If you found this post informative please share. Also, don’t hesitate to get in touch if you have any questions or need advice –

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