Last Updated on September 1, 2026 by Umar Farooq
A dehumidifier in bathroom use is a bad idea, and usually an impossible one. It is a mains appliance and a bathroom is a wet room — and in the UK the question mostly settles itself, because there is nowhere legal to plug one in. Electrical Safety First is unambiguous: standard socket outlets are not permitted in a bathroom or shower room unless they are at least 3 metres from the edge of the bath or shower zone. In an ordinary domestic bathroom, that is nowhere.
The good news is that the fix is easier than the machine anyway, and a dehumidifier on the landing does most of what you wanted from one inside.
Is a dehumidifier in bathroom use ever safe?
Whether a dehumidifier in bathroom conditions is safe is one of the few questions here where credible people say opposite things. The founder of Meaco, a UK manufacturer, has said plainly that it is not safe to use electrical appliances in a UK bathroom. Several US and international sites say the opposite.
Both can be right, because they are answering under different wiring rules. UK bathroom zoning under BS 7671 effectively removes the socket you would need. Elsewhere a properly RCD-protected outlet at a sensible distance may exist.
So the answer is jurisdictional: in the UK and Ireland, do not; elsewhere, only with a protected outlet well away from the bath, and check local regulations. What nobody disagrees about is that the landing is safer and nearly as effective.
The four things that actually fix a damp bathroom
1. Run the extractor fan properly. During the shower and for twenty minutes afterwards. Most bathroom fans go off the moment the light does, which is exactly when the room is wettest. A humidity-sensing fan or a timer overrun fixes that permanently for less than a dehumidifier costs.
It is the highest-value change and the one people skip because it is not a purchase. A working extractor beats a dehumidifier every time, because it takes moisture out of the building rather than moving it around inside.
2. Open the window, or the door onto the landing. Free, and ten minutes of cross-ventilation after a shower beats an hour of any appliance — provided the outside air is drier.
3. Squeegee the screen and wipe the tiles. Unglamorous, and it works. Every drop you remove by hand is a drop nothing has to condense back out of the air later.
4. Only then, a dehumidifier — on the landing. With the door left open afterwards, moisture migrates out to the dry spot it creates. Not a compromise: that is how placement works, and a landing unit dries a whole floor.
What a dehumidifier can and cannot do about bathroom mould
It holds the air below 60%, above which mould can establish on a suitable surface within 24 to 48 hours. That genuinely prevents new growth.
What it cannot do is deal with what is actually happening in most bathrooms: condensation on cold surfaces rather than high room humidity. Air at 20°C and 50% RH landing on a surface at 12°C sits at roughly 84% humidity at that surface, so a cold tiled wall runs with water even when the room reading looks respectable.
That is why the black speckling appears in the same three places every time — the window reveal, the ceiling corner, the grout in the coldest corner. Insulation, heating and ventilation change the surface temperature; a dehumidifier only changes the room reading. More on dehumidifiers and mould.
And it will not clean off mould that has already grown. That is a cloth-and-cleaner job, and above about a square metre, the EPA’s guidance is worth reading before you start.
The one thing that is fine inside a bathroom
Non-electrical absorber tubs. Calcium chloride crystals in a pot, with no cable and nothing to shock anybody. Perfectly sensible inside a bathroom cupboard, in a windowless en suite, or on a shelf in a small shower room.
Be realistic about capacity: a tub collects a few hundred millilitres over a month, against the litre or two a hot shower adds in ten minutes. Fine for a musty cupboard, hopeless for a family bathroom. The arithmetic on absorbers.
If you are going to put a machine near the bathroom anyway
- On the landing or in the hallway, not on the threshold where it gets splashed.
- Bathroom door open after showering, so moisture can reach it.
- 50% setting. Lower does not dry faster.
- 30 cm clear at intake and outlet.
- Never on a wet floor, or where a towel can fall over the outlet.
Never run an extension lead from a landing socket into a bathroom to reach a dehumidifier. That defeats the entire purpose of the wiring rules, and a trailing lead across a wet floor is exactly the hazard those rules exist to prevent. If the machine cannot reach from a safe socket, it goes somewhere else.
Frequently asked questions
Can you put a dehumidifier in a bathroom?
In the UK, effectively no — standard sockets are not permitted in bathrooms unless they are at least 3 metres from the bath or shower zone, which rules out most domestic bathrooms. Elsewhere it depends on local wiring rules, and the landing is safer regardless.
Where should I put a dehumidifier for a damp bathroom?
On the landing or in the hallway outside, with the bathroom door left open after showers. Damp air migrates towards the dry spot the machine creates, so it captures most of the moisture without a mains appliance in a wet room.
Will a dehumidifier stop mould in a bathroom?
It will stop the humidity that feeds new growth, but most bathroom mould is driven by condensation on cold surfaces rather than by high room humidity. Ventilation, heating and insulation change the surface temperature; a dehumidifier only changes the room reading.
Is an extractor fan better than a dehumidifier for a bathroom?
Yes, comfortably. An extractor removes moisture from the building; a dehumidifier moves it around inside and returns the heat. Run the fan during the shower and for twenty minutes afterwards, and most bathrooms need nothing else.
Can I use a moisture absorber tub in a bathroom?
Yes — non-electrical absorbers are perfectly safe in a wet room. Be realistic about capacity, though: a tub collects a few hundred millilitres over a month, which is far less than a family bathroom generates.
Why does my bathroom still get damp with a dehumidifier running?
Almost certainly because the machine is outside a closed door, or because the problem is condensation on cold tiles rather than humid air. Leave the door open after showering, and check whether the wet patches are always on the coldest surfaces.
Should I run a dehumidifier in an en suite with no window?
Not inside it. Fit or repair the extractor fan first — a windowless en suite legally needs mechanical ventilation anyway — and put any dehumidifier in the bedroom outside with the door open.
Related guides: Where to put a dehumidifier · Does a dehumidifier help with mould? · Natural dehumidifier methods · How to dehumidify a room
Sources
- Electrical Safety First — Are you allowed to have a socket in the bathroom? — the UK rule on socket outlets in bathrooms and shower rooms.
- Electrical Safety First — Bathroom safety — RCD protection and general bathroom electrical guidance.
- EPA — Mold Course, Chapter 2 — the 60% threshold and how surface conditions differ from room air.
- EPA — Mold Cleanup in Your Home — what to do about mould that has already grown, and when a job is too big to tackle yourself.
Where this guide and your appliance’s own manual disagree, follow the manual. And if your bathroom fan has never run for more than the length of a shower — go and look at whether it has an overrun timer. That one change fixes more bathrooms than any appliance I could sell you.
