Magnetic Filter Installation Costs UK — What to Charge to Supply and Fit a MagnaClean in 2026

What a Magnetic Filter Is and Why You Fit One

A magnetic system filter — a MagnaClean, Adey MagnaClean Professional, Fernox TF1, Spirotech or similar — is an inline canister fitted to the central heating pipework. Inside sits a powerful magnet that captures magnetite (black iron-oxide sludge) as the system water passes through. Over time, steel radiators and components corrode internally and shed iron oxide. That sludge circulates, settles in radiator bottoms causing cold spots, and clogs the heat exchanger and pump.

The filter strips that magnetite out of the water before it can damage the expensive parts. A clean magnet means a protected boiler, a longer-lasting pump and better radiator performance. There's also a commercial reason customers care: most boiler manufacturers now require a magnetic filter to be fitted (and inhibitor dosed) as a condition of the extended warranty. Under the Benchmark commissioning scheme, recording the filter and inhibitor on the logbook is part of validating that guarantee. No filter, and the homeowner risks a refused warranty claim down the line — which is a strong line to use when you're recommending one.

Where It Goes

The filter is almost always fitted on the central heating return — the pipe carrying water back to the boiler — as close to the boiler as practical and before it re-enters the appliance. That position catches the dirty water on its way back from the system before it passes through the heat exchanger again. It needs to sit vertically or horizontally depending on the model, with enough clearance underneath or to the side to remove the magnet and flush the canister during servicing.

On most installs the obvious spot is the 22mm pipe in the airing cupboard or under the boiler. The job is simplest when there's a straight, accessible run of pipe with room to cut in two isolation valves and the filter body. It gets fiddlier — and pricier — when the return is buried, boxed in, tight against a wall, or in plastic pipe that needs different fittings.

Typical Price Bands and Worked Examples

Magnetic filter pricing falls into a few clear tiers depending on access and whether the system needs draining. Here's how the jobs break down with worked examples.

Standard Supply and Fit — Accessible Pipe

This is the everyday job: a clear length of 22mm copper return, room to work, and only a partial drain-down of the immediate section needed (or a freeze kit used to avoid draining at all). You cut in the filter and its two service valves, fit it, refill, top up the inhibitor and check for leaks.

• Supply and fit on accessible pipe: £120–£250
• Typical time on site: 1–2 hours

Worked example: A customer wants a filter fitted on an exposed 22mm return in the airing cupboard. You buy the filter for around £75 trade, allow a bottle of inhibitor at roughly £10, and price 1.5 hours' labour. Quote £180 supplied and fitted. Parts cost you about £85, leaving roughly £95 of labour value — a tidy half-morning job.

Trickier Installs — Pipework Alterations or Full Drain-Down

When access is poor, the pipe needs re-routing, the run is boxed in, or the whole system has to be drained and refilled to make room for the filter, the labour climbs. You might be altering pipework, fitting elbows to bring the filter to an accessible position, or spending extra time draining a stubborn system and bleeding every radiator on the refill.

• Install needing pipework alterations or a full drain and refill: £250–£400+
• Typical time on site: half a day

Worked example: The return is buried behind a boxed-in section and the nearest accessible pipe is a foot away. You drain the system, alter the pipework to bring the filter out where it can be serviced, fit it, refill, re-dose inhibitor and bleed the rads. That's a 4-hour job with extra fittings — quote £320–£360. The filter and bits cost you around £100; the rest is labour for the access work.

As an Add-On to a Power Flush or Boiler Install

A magnetic filter is almost always done alongside a power flush — you flush the system to remove existing sludge, then fit the filter to keep it clean going forward. It's also a near-standard line on any new boiler install. When you're already on site with the system drained or open, the marginal labour to add a filter is small, so you can offer it keenly while still making good margin.

• Filter added to a power flush (system already open): £90–£160
• Filter added to a new boiler install: £100–£180

The filter unit and a power flush are separate things — the flush cleans the existing dirt out of the system, the filter stops new sludge causing damage. Customers often confuse the two, so be clear in your quote that you're recommending both: one cleans, one protects. Pricing the filter as its own line, even when bundled, shows the value and keeps the warranty paperwork clean.

The Cost Split: Filter Unit vs Labour

On a typical standalone install, roughly half the price is the filter unit and consumables and half is your labour. Knowing the split helps you quote confidently and explain the price if a customer queries it.

• Filter unit: £55–£110 trade depending on brand and size. Branded units (Adey, Fernox, Spirotech) sit at the higher end; budget filters cheaper but harder to defend to a quality-conscious customer.
• Service valves and fittings: £10–£30 — isolation valves either side make future servicing a five-minute job rather than another drain-down.
• Inhibitor: £8–£15 for a bottle of corrosion inhibitor dosed on refill (required for the warranty and good practice regardless).
• Labour: the balance — 1 to 4 hours at your hourly or day rate depending on access.

Don't forget the service valves. Fitting them at the same time as the filter costs you a few pounds and a few minutes now, but means every future filter clean — yours or another engineer's — is quick and clean. It's the mark of a tidy install and worth flagging to the customer as a feature, not a hidden extra.

What Affects the Price

Two filter installs are rarely identical. These are the factors that move your quote up or down — check them before you commit a number.

• Pipe size: 22mm is standard on most domestic systems and what most filters are sized for. A 28mm return (larger or older systems) may need a different filter variant or reducers, adding parts cost and time.
• Pipe material: Copper is straightforward to cut and solder or use compression fittings. Plastic pipe (push-fit) needs the right inserts and fittings and a different approach — factor it in.
• Access: A clear pipe in an airing cupboard is the easy case. Buried, boxed-in, low under a combi or jammed against a wall all add labour.
• Whether the system needs draining: A partial drain or a freeze kit keeps a job short. A full drain and refill — and bleeding every radiator afterwards — can double your time on site.
• Adding inhibitor: Always dose inhibitor on the refill. It's a small cost but essential for the warranty and the system's health, so include it in every quote.
• Filter brand: If the customer or the boiler manufacturer specifies a particular brand for warranty reasons, that can dictate which unit you fit and what it costs you.

Why It's a Strong Upsell

The magnetic filter is one of the best-value upsells in the trade, for both you and the customer. The marginal effort is low — especially when you're already on site for a service, a power flush or a boiler swap — and the benefits are easy to explain: it protects an expensive boiler, helps validate the warranty, keeps radiators hot to the bottom and extends the life of the pump.

The warranty angle is the closer. When a customer learns their boiler guarantee may depend on a filter being fitted and inhibitor recorded on the logbook, the £150–£200 spend looks like cheap insurance against a refused claim on a £2,000+ appliance. Frame it that way and most say yes. Offer it on every service and every install, present it as protecting their investment rather than an add-on, and it becomes a steady source of low-effort, high-margin work.

Quick Reference: Magnetic Filter Prices UK 2026

How to Quote It

A clean quote for a filter install wins the job and protects your margin. A few habits:

• Check the pipe first. Confirm size (22mm or 28mm), material (copper or plastic) and access before you price. A two-minute look in the airing cupboard saves you from a job that turns out to need a full drain-down.
• Itemise the filter and inhibitor. Show the filter unit, the inhibitor and the labour as separate lines. It justifies the price and keeps the warranty paperwork tidy.
• Lead with the warranty. Note on the quote that the filter and inhibitor help validate the boiler manufacturer's guarantee and are recorded on the Benchmark logbook. That reframes the cost as protection.
• Offer it as a bundle. When quoting a power flush or boiler install, include the filter as a line so the customer sees the full protected-system package.
• Price the access risk in. If you can't see the return clearly, quote the higher band or add a note that buried pipework may increase the cost — don't absorb a surprise drain-down.

FAQ

How much should I charge to fit a magnetic filter?

For a standard supply-and-fit on accessible 22mm copper, £120–£250 is the going rate in 2026. Jobs needing pipework alterations or a full drain and refill run £250–£400+. As an add-on to a power flush or boiler install, where the system is already open, £90–£180 is fair.

Is a magnetic filter the same as a power flush?

No. A power flush cleans existing sludge out of the system; the filter is a permanent unit that catches new magnetite to stop future damage. They're often done together — flush first, then fit the filter to keep it clean — but they're separate jobs and separate charges.

Where does the filter go?

On the central heating return, as close to the boiler as practical and before the water re-enters the appliance, with enough clearance to remove the magnet for servicing.

Does fitting a filter affect the boiler warranty?

For most manufacturers, fitting an approved magnetic filter and dosing inhibitor is a condition of the extended warranty, recorded on the Benchmark logbook. Without it, the homeowner risks a refused claim — which is exactly why it's an easy recommendation.

Should I fit service valves with the filter?

Yes. Isolation valves either side of the filter cost a few pounds and a few minutes now, but make every future filter clean a quick job with no drain-down. It's the mark of a tidy install.