A heated bathroom mirror, also called a demister mirror, has a thin heating pad fixed to the back of the glass. It comes on with the light and warms the mirror just enough that steam cannot settle on it, so you step out of the shower to a clear mirror with nothing to wipe. This guide explains how a demister pad works, what to look for, and when you can do without one.
What is a demister pad?
A demister pad is a flat heating element, usually a printed film, bonded to the back of the mirror glass. When the mirror is switched on, the pad raises the temperature of the glass a little above the air in the room. Condensation forms when warm, wet air meets a cold surface, so a glass that is slightly warmer than the air stays clear. The pad is hidden behind the mirror, there is nothing to see from the front, and it is wired into the same supply as the LED light.
Every mains-powered Sensio LED bathroom mirror and mirror cabinet has a demister pad built in. Our battery operated mirrors do not, because a heating pad would drain the battery, so if a clear mirror after a shower matters to you, choose a wired mirror.
Nebula Round LED mirror in black, demister close-up.
Does a heated mirror use much electricity?
Very little. A demister pad only needs to warm the glass by a few degrees, so it draws a small fraction of what a bathroom heater or towel rail uses, and it only runs while the mirror light is on. In practice the cost is pennies a week.
How long does it take to clear?
The pad starts warming the glass as soon as the light is switched on. If you turn the mirror on when you start your shower, the glass is usually clear by the time you finish. If you turn it on afterwards, the mist clears from the centre outwards over a few minutes without wiping.
Is a heated mirror safe in a bathroom?
Yes, provided it carries the right IP rating for where it is fitted. Sensio mains mirrors and cabinets are IP44 rated, which means they are protected against splashing water and are suitable for bathroom zone 2, the area around the basin and 600mm beyond the bath or shower. They are not for use inside the shower enclosure. All mains bathroom mirrors must be wired in by a qualified electrician. If you are not sure which zone your wall is in, read our bathroom zones and IP ratings guide.
What to look for when choosing a demister mirror
Size of the pad. On smaller mirrors the pad covers most of the glass. On larger mirrors it is usually a central panel, which is where you look, so the edges may mist while the centre stays clear.
How it switches. On Sensio mirrors the demister comes on with the light, using the touch or infra-red sensor on the mirror. There is no separate switch to remember.
Light colour. Most of our demister mirrors use TrioTone® or CCT, so you can set warm, natural or cool white. Natural and cool white show skin tone most accurately for shaving and make-up.
Shape and finish. Demister mirrors come in round, rectangle, arch, pill and oval shapes, frameless or framed in black, brushed brass and gunmetal.
Storage. If the mirror is above a basin with no cupboard space, a mirror cabinet with a demister gives you a clear mirror and somewhere to put things. Many of ours also have a shaver socket inside.
Maris Round LED bathroom mirror in gunmetal.
Do you need one?
If your bathroom has a shower and the mirror is anywhere near it, yes. A mirror that steams up every morning is one of the most common complaints about bathroom lighting, and a demister pad fixes it for very little running cost. If the mirror is in a cloakroom or a well ventilated bathroom with a bath only, you may never miss it, and a battery operated mirror becomes an option where there is no wiring.
Frequently asked questions
Can I add a demister pad to an existing mirror?
Retro-fit pads exist, but they need a mains connection behind the mirror and a qualified electrician to fit them. For most bathrooms it is simpler to replace the mirror with one that has the pad built in.
Does the demister pad stay on all the time?
No. It runs only while the mirror light is on and switches off with it.
Will the heat damage the mirror?
No. The pad warms the glass by a few degrees, well within what mirror glass is designed for. Sensio bathroom mirrors carry a 7 year guarantee and the mirror glass is guaranteed for 12 months, excluding accidental damage.
Do battery mirrors have demisters?
No. A demister pad needs mains power. Battery operated mirrors are for walls with no wiring where a clear-after-shower mirror is not the priority.
See all our heated and demister bathroom mirrors, or browse every LED bathroom mirror.
