Lights and humidity: kitchen, bathroom, cellar, choosing well

Lights and humidity: that is the question to ask before lighting a kitchen, a bathroom or a cellar. A suitable IP rating, the right electrical class and a material that copes with steam are enough to get durable, safe light, without giving up on style.

Water and electricity never meet without precautions. But between a walk-in shower, a worktop next to the sink and a slightly chilly cellar, the constraints are not at all the same.

Here is how to read a light's specifications, choose according to the room and avoid the pitfalls of condensation.

1. Why humidity damages a light

Water vapour gets in everywhere: into the lampholder, the terminal blocks, behind the mounting cover. It can cause oxidation on the contacts, a leakage current that trips the RCD or, over time, stains and swelling on some materials. A light does not need to get wet to suffer: a room where the air stays laden with moisture is enough.

2. The IP rating: the first figure to read

The IP rating shows the protection against solid objects (first digit) and against water (second digit). For humidity, it is the second digit that counts. Our article understanding IP20, IP44, IP65 explains it in detail.

3. The electrical class: the other half of safety

The class tells you how the light protects you from contact with a live part. A Class I light must be earthed, a Class II light is double insulated, and a Class III light runs on safety extra-low voltage. The symbol is on the label: see what the class symbol means.

In a damp room, the class matters as much as the IP rating. A metal Class I light is only safe if the green and yellow wire is properly connected to the earth of the installation. In an older home without an earth, a Class II model avoids this problem, since its double insulation does not depend on any connection.

4. Bathroom: respecting the zones

The wiring regulations (BS 7671) divide the bathroom into zones around the bath and the shower. Each zone sets a minimum IP rating and class. The details are in our articles on bathroom zones and the key wiring rules.

For mirror lighting, which is often outside the zones, follow our guide to the bathroom wall light, and for the ceiling our bathroom ceiling light guide.

5. Kitchen: steam, grease and splashes

The kitchen does not have regulated zones like the bathroom. The constraints come from cooking steam, splashes near the sink and grease settling on the shades. Above the sink, a closed wall light or an IP44 model gives more peace of mind. Above an island, a standard pendant works very well if the cooker hood does its job. See our guide to the kitchen wall light.

6. Cellar, utility room and basement

The cellar combines coolness, little air circulation and sometimes damp walls. A light rated at least IP44 is the right reflex, ideally closed with a diffuser. In a utility room, steam from the tumble dryer and splashes from the sink call for the same precautions. Our guides to the cellar wall light and the utility room wall light detail suitable models.

A placement tip: fix the light to the ceiling or high on the wall, away from areas where you water, wash or where water runs down if there is a leak. And if the wall is constantly damp, deal with the damp first: no light is happy for long in a room that never dries out.

7. Condensation, the hidden enemy

Condensation appears when warm, moist air meets a cold surface: the glass of a switched-off light, an outside wall, a cellar ceiling. Droplets can then form inside the diffuser itself.

• Air the room after every shower and leave the extractor fan running.
• Avoid placing a light against a cold, poorly insulated wall in a damp room.
• If water appears in a diffuser, switch off the power and have the seal checked.

8. Which materials to choose in damp conditions

Stone deserves a mention: its porosity makes it sensitive to limescale marks, without stopping it from dressing a bathroom outside the zones.

9. Bulbs and LEDs in damp conditions

LEDs cope well with damp rooms provided the light is suitable. On a model with integrated LED, the sealing is designed in from the start. On a model with a bulb, the seal around the diffuser does most of the work. A bulb that flickers in a damp room means the lampholder should be checked: oxidation sometimes builds up there.

In a bathroom, also choose a warm shade of around 2,700 to 3,000 K: the light stays flattering on the skin, and a high colour rendering index helps with make-up or shaving.

10. Installation and care

An IP44 light is only watertight if it is fitted correctly: cable gland tightened, seals in place, fixings correctly oriented. On an exterior wall the same principles apply, see sealing and fixing on an exterior wall.

11. In short

Lights and humidity get along well with three reflexes: read the IP rating, check the electrical class and choose a material suited to the room. In the bathroom, the zones dictate the choice. In the kitchen and cellar, a closed IP44 model gives peace of mind.

Frequently asked questions