Magnetic Filter Guide: Why You Need One & What It Costs

If your home relies on a hydronic central heating system that circulates water through pipes, radiators, and towel rails, chances are that your system is susceptible to sludge problems. And one of the surest ways to prevent heating sludge from building up and clogging your boiler, pipes, and rads, is to install a magnetic filter.

In this post, we will explain how a magnetic filter works, why your central heating system and boiler sorely need one, and list the top 4 magnetic filter models on the market in 2024.

Why Your Heating System Needs a Magnetic Filter

Central heating systems are made up of various metals. Over time, the metals degrade and circulate through radiators, towel rails, pipe work, and eventually the boiler.

This debris build up is known as heating sludge, and over time, it accumulates throughout the heating system. One of the most common symptoms of heating sludge accumulation is radiators with cold spots at the bottom. That said, this goo-like substance can end up anywhere in the system, including the boiler’s expensive components (like a heat exchanger).

To prevent sludge from clogging up your pipework, radiators, and boiler, a magnetic filter hangs on the pipe that returns water to the boiler and catches this debris as it circulates with the flow of water. Some of the boiler’s parts are extremely expensive to fix, and a magnetic system filter is the best way to protect them.

To learn more about how magnetic filters can help, flick through this video from MagnaClean. It will show you the impact magnetic filters will have on the water in your central heating system, and how they’ll help you avoid a sludge problem.

Why a Magnetic System Filter Is Not an Alternative to an Inhibitor

An inhibitor breaks down sludge that’s accumulated in central heating, and a filter picks up this fragmented debris. As you can see, without the inhibitor, the sludge would build up instead of floating around freely, and the magnetic filter would not be able to catch it.

This is why it’s wrong to view an inhibitor as an alternative to a filter. The two are not interchangeable: you need a magnetic filter and the inhibitor to keep the boiler and central heating system free of sludge.

Top 4 Central Heating Filters [and What They Cost]

After speaking to a few engineers (and checking best sellers from local merchants) we’ve zeroed in on 4 magnetic boiler filter models. Prices below are for 22mm filters. Now, be aware that some gas runs will be 28mm, so note that the 28mm filters are slightly more expensive.

The MagnaClean Range from Adey

Price: from £70 for the MagnaClean Micro, and £85-90 for the MaganaClean Professional Chemical Pack. We’ve created a guide to MagnaClean Filters here, and a review of the MagnaClean Professional 2 here.

Adey are one of the most well-known brands in this space, and their prices are reasonable. For instance, the Micro magnetic filter is one of the cheapest on the market. However, if you have the budget for it, you should opt for the larger filter in their range — the Professional Chemical Pack.

Fernox TF1 Magnetic Filter

Considering that it’s a well-known brand, the Fernox TF1 filter is an excellent buy, and most reviewers seem happy with its performance.

You can check out our Fernox TF1 Boiler Filter review here.

Worcester System Filter

If you have a Worcester Bosch boiler, it’s wise to go with their own brand filter.

Likewise, if you’re thinking about getting a Worcester Bosch boiler, a magnetic filter from the same brand is a great add-on —  getting it will increase your boiler warranty by 1 year.

That said, if you’re looking for a new boiler from Worcester, be sure to check out Heatable. They’re an online boiler installation company that fits Worcester boilers at low prices and always includes magnetic filters with the purchase — at no extra cost to you. Heatable also offer 10-year warranties with all the boilers they fit, so you can rest assured that your appliance will last a while without additional expenses on your end.

You can get your own fixed priced boiler quotes from Heatable by filling in thier anonymous, 90-second questionnaire.

Instinct Eco-Mag

The Instinct Eco-Mag is an excellent magnetic system filter, and one of the better budget options.

Cost to Install a Magnetic System Filter

The cost to install a magnetic system filter will depend on your choice of filter, and whether you have a 22mm or 28mm gas run.  The accessibility of the installation area will also affect the price — the easier it is to install, the less you’ll pay.

Overall, though, you can expect to pay around £90-125 for the installation alone, so you’ll part with roughly £200-250 in total.

Magnetic Filter Maintenance

If you already have an annual boiler service, ask your Gas Safe engineer to include filter maintenance as part of the deal. All filters come apart quite easily and it’s a simple case of cleaning them out and checking for any wear and tear.

If you don’t already have an annual boiler service, it’s a worthwhile service that will help to protect your heating system. You can learn about the costs associated with a boiler service here.

What’s Next

We hope our guide to magnetic system filters helped you understand how these devices work, why you need one fitted, and how much you can expect to pay.

Is there anything that we missed? Do you have an experience with a magnetic filter that you’d like to share? If you do, or if you have any other questions, please leave us a comment below.