How to measure for a radiator cover

A radiator cover lives or dies by its measurements. Get them right and the cover slips over the radiator, clears the valves, sits flat to the wall and lets the heat through. Get them wrong and you are left with a cover that fouls a valve, traps the heat or stands proud of the skirting. The good news is that measuring is straightforward once you know what to record: three main dimensions, a clearance allowance, and a note of the pipes, valves and skirting. This guide walks you through all of it, so you order the right size first time and avoid the cost and hassle of sending a cover back.

What you'll measure

Start with the radiator itself and take three measurements, in millimetres if you can, as covers are usually sold that way:

• Width. The full width of the radiator, measured to the outside of the valves at each end, not just the radiator body.
• Height. From the floor to the top of the radiator, including any valves or pipework that sit below it.
• Depth. How far the radiator stands out from the wall, including the brackets and the valves at the front if they protrude.

Write each one down as you go. The single most common mistake is measuring the radiator body alone and forgetting the valves, which usually add width at the ends and height below, so always measure to the outside of everything that sticks out. If you have more than one radiator to cover, label each set of measurements by room, since it is surprisingly easy to mix up two similar-looking radiators once you have several figures on the page.

Add clearance for airflow

A cover should never touch the radiator. It needs a margin all round so air can move and the cover stays cool, which protects both your heat and the cover itself. As a rule of thumb, allow a clear gap on each side, above the radiator and at the front, commonly a few centimetres, though the exact allowance varies by product.

That clearance does two jobs: it keeps the warm metal away from the cover, and it leaves room for the convection current to flow up and out. When you choose a stock cover, compare its internal dimensions, not just its outside size, against your radiator plus this clearance.

Remember the airflow openings as well. The cover wants a gap at the bottom for cool air to enter and a vented or open top for warm air to leave, so do not plan to seal it tight against the floor or fit a solid shelf flush to the wall. Fit and airflow go hand in hand.

Clearance also makes a cover easier to live with. A little room around the radiator means the cover can be lifted off or swung open for cleaning, bleeding the radiator or reaching the valves, and it stops the heat discolouring or warping the panel over time. So the margin is not wasted space; it is what keeps the cover working and looking good for years. When in doubt, err towards a touch more clearance rather than a tight squeeze.

Measuring around pipes and valves

This is where most covers come unstuck, and where a careful measurement pays off. Note where the pipes rise out of the floor or wall, and where the valves and any thermostatic valve (TRV) sit at each end. Measure their positions: how far in from each end, and how high from the floor.

A stock cover may simply clear them, but if a valve or pipe sits where the cover's side or frame would go, you have two choices: a larger stock size that clears it, or a made-to-measure cover built with a cut-out or extra clearance in exactly the right place.

Pay special attention to the TRV. A thermostatic valve shut inside a cover reads the warm air trapped around it and turns the radiator down too early, so the aim is to keep it exposed to the room or allow proper airflow around it. Record its exact position so a made-to-measure cover can be built to leave it clear.

For why TRV placement matters so much, see should TRVs be inside or outside a radiator cover?

Scribing to skirting

If your radiator sits above a skirting board, as most do, the cover has to deal with it. A flat-backed cover pushed against the wall will stand proud by the depth of the skirting, leaving a gap at the bottom and sides that looks unfinished and lets the cover rock. The tidy solution is scribing: the bottom and sides of the cover are cut to follow the skirting profile so the cover sits flush to the wall. Stock covers rarely scribe neatly, which is one of the main reasons people move to made-to-measure for a built-in look. Measure the height and depth of your skirting so the cover can be cut to clear or follow it.

The same goes for any other obstruction along the wall: a window sill that overhangs, a power socket, a TV cable or a run of pipework. Note anything that sits in the footprint the cover will occupy, with its position and size, so it can be accommodated rather than discovered on fitting day. A few extra measurements here are what turn a cover that almost fits into one that looks like it was always meant to be there.

Before you start

Measuring takes only a few minutes, but a little preparation makes it accurate. You will need a steel tape measure (a fabric one sags and misreads), a pen and paper or your phone to record each figure, and ideally a second pair of hands for a wide radiator so the tape stays level. Work with the heating off and the radiator cool, so you are not measuring near hot metal. Take each measurement twice and write it straight down; it is far easier to check a number now than to discover a cover does not fit after it arrives. If you can, measure in millimetres throughout, since that is how covers are usually specified.

Common measuring mistakes

Most ill-fitting covers come down to the same handful of slips, all easy to avoid:

• Measuring the radiator only. Forgetting the valves, which add width at the ends and height below, is the classic error; measure to the outside of everything.
• No clearance. Buying a cover the same size as the radiator means it touches the hot metal and traps heat; always add a margin.
• Ignoring the skirting. A flat-backed cover stands proud of skirting, so note the skirting depth or plan to scribe.
• Outside vs inside size. Comparing your radiator to a cover's external size, not its internal dimensions, leaves no room inside.
• Rounding or mixing units. Switching between centimetres and millimetres, or rounding up, stacks up into a poor fit.

Run through this list before you order and you will catch almost every problem while it is still just a pencil mark on a notepad rather than a cover that has to go back.

How to measure, step by step

1. Measure the width of the radiator to the outside of the valves at each end.
2. Measure the height from the floor to the top of the radiator, including valves and pipework below.
3. Measure the depth from the wall to the front of the radiator, including brackets and front valves.
4. Add clearance on each side, above and at the front, so the cover never touches the radiator.
5. Note the pipes and valves: where they rise and sit, measured in from each end and up from the floor, plus the TRV position.
6. Note the skirting height and depth so the cover can be scribed or cut to clear it.
7. Compare or order: match your figures to a stock size's internal dimensions, or send them for a made-to-measure cover.

Measure	Don't forget
Width	To the outside of the valves, not just the body
Height	Include valves and pipework below the radiator
Depth	Include brackets and front-facing valves
Clearance	A margin all round so nothing touches
Pipes, valves, TRV	Their exact positions for cut-outs
Skirting	Height and depth, to scribe or clear it

Measuring FAQs

How do I measure for a radiator cover?

Measure the radiator's width, height and depth (to the outside of the valves), then add clearance so the cover does not touch it, and note any pipes, valves, the TRV and skirting. For awkward results, order made-to-measure built to your figures.

How much clearance does a radiator cover need?

Allow a margin around the radiator, commonly a few centimetres on each side, above and at the front, so air can move and the cover is not touching hot metal. This protects both the airflow and the cover. The exact allowance varies by product, so check each cover's internal dimensions.

How do I measure around pipes and a TRV?

Note where the pipes rise and where the valve and TRV sit, and measure their positions in from each end and up from the floor. A made-to-measure cover is then built with the right cut-outs and clearance (linking when live).

Should I measure in millimetres or centimetres?

Either works, but millimetres are best, because covers are usually specified in millimetres and it avoids rounding errors. Whatever you use, keep every measurement in the same unit and write them down as you go, so nothing gets mixed up at the order stage.

What if my measurements fall between stock sizes?

That is the moment to go made-to-measure. Forcing a stock size that is slightly too small or too large means a poor fit and often trapped heat. A made-to-measure cover is built to your exact figures. Compare stock options first on radiator covers by size.

Do I need to measure the wall as well as the radiator?

Yes, both. Measure the radiator so the cover clears it, and measure the wall space so the cover fits the spot without fouling a door, window, sill or socket. The cover has to be larger than the radiator yet still suit the wall, so the two sets of measurements together point you to the right size.

Can I measure for a cover myself, or do I need a fitter?

Most people can measure their own radiator with a steel tape in a few minutes by following the steps above. A fitter or joiner is only really needed if the space is unusually awkward, or if you want a cover scribed and fixed for a flush, built-in finish; even then, accurate measurements from you make their job quicker.

Order made-to-measure radiator covers built to your measurements, or browse radiator covers by size if a stock size fits. Free UK delivery and 365-day returns. Big brands, small prices.