Key Takeaways
- Good lighting uses three layers: ambient, task and accent, all dimmable.
- Specify lumens, not watts. A 60W incandescent gave about 800 lumens; an LED gives the same on 7W to 9W.
- CIBSE targets are 300 lux in a kitchen, 150 in a living room or bathroom and 100 in a bedroom, with 500 lux at a worktop.
- Use 2,700K in living rooms and bedrooms, 3,000K to 4,000K in kitchens, bathrooms and offices.
- Circuits and switching are set at first fix. Adding them later means chasing finished walls and replastering.
Lighting is one of the most underrated parts of a renovation, yet it shapes how every room looks and feels. Planned well and early, it costs little; added late, it means tearing into finished walls. Here is how to get it right.
Light in three layers
Great lighting combines three layers, ideally all dimmable:
- Ambient: general background light that fills the room, usually downlights or a pendant, and the layer people over-specify.
- Task: focused light where you work. Under-cabinet strips at the worktop, a mirror light at eye level in a bathroom, a reading lamp beside a chair.
- Accent: decorative highlights on artwork, shelving, a splashback or a stair, at roughly three times the surrounding level so the eye reads them as bright.
A single ceiling light does none of this well. It also puts the light source behind you at a worktop or a mirror, so your own body casts the shadow onto the thing you are trying to see, which is the single most common fault we are called back to fix.
How many lumens does a room need?
Work in lumens and lux, never watts, because wattage now tells you only what a fitting consumes. Lux is lumens landing on a square metre of surface, so multiply the target lux by the floor area, then add roughly a quarter for the light lost to fittings, dirt and pale-but-not-white surfaces. A 12m² kitchen at 300 lux therefore wants about 4,500 installed lumens in the ambient layer, with the task layer on top.
| Room | Target illuminance | Install roughly | Colour temperature |
|---|---|---|---|
| Kitchen, general | 300 lux | 375 lm per m² | 3,000K to 4,000K |
| Kitchen worktop, task | 500 lux | 400 to 600 lm per metre of run | 3,000K to 4,000K |
| Living room | 150 lux | 190 lm per m², split across layers | 2,700K |
| Bedroom | 100 lux | 125 lm per m² | 2,700K |
| Bathroom | 150 lux, 300 at the mirror | 190 lm per m² plus a mirror light | 3,000K to 4,000K |
| Home office | 300 to 500 lux at the desk | Task lamp of 400 to 800 lm | 4,000K |
Which colour temperature?
Warmer where you relax, cooler where you work. 2,700K is the domestic default, the warm light people associate with home, and it belongs in living rooms, bedrooms and hallways. 3,000K is the compromise for a kitchen-diner that does both jobs. 4,000K is neutral white, right over a worktop, mirror or desk and wrong over a dining table. Keep every fitting in one sightline to the same temperature, because a 2,700K pendant beside a 4,000K downlight looks like a fault, and specify CRI 90 or better anywhere you cook or dress.
Plan it at first fix
Lighting circuits and positions are set during first fix, before plastering, and that deadline is the whole point. Once walls are skimmed, adding a switch drop or a circuit means chasing the wall, replastering, redecorating and losing the room for a week. Before first fix you need a plan showing every fitting, switch position and dimmer, and which fittings sit on which circuit.
Split each room across at least two circuits so the layers control separately: downlights on one, pendants and accents on another. Put two-way switching at both ends of a hall, a stair and any room with two doors. Check dimmer and driver compatibility as a pair, since a mismatched trailing-edge dimmer is the usual cause of flickering LEDs. New circuits and any work in a bathroom are notifiable under Part P, so it needs an electrician on a competent person scheme or notification to building control. If the house is being rewired anyway, this is the moment: see rewiring costs, signs you need a rewire and the order of works.
Source: gov.uk, Approved Document P, Electrical safety, dwellings, and BS 7671 Requirements for Electrical Installations, 2026.Room by room
Kitchens need the task layer in front of you, not behind. Put continuous LED strip under the wall units at 400 to 600 lumens per metre, and if there is an island, hang pendants so the bottom of the shade sits 750mm to 900mm above the worktop, high enough to see across and low enough to light it. Downlights belong roughly 700mm out from the wall so they land on the worktop edge rather than the cabinet doors.
Bathrooms are zoned under BS 7671. Zone 0, inside the bath or shower, needs IPX7. Zones 1 and 2, above the bath to 2.25m and 0.6m beyond, need at least IPX4. Light the mirror from both sides at face height rather than from a downlight overhead, which shadows the eyes. Living rooms and bedrooms gain most from dimming and from lamps at low level, because a room lit only from the ceiling feels like a corridor. Plan five-amp lamp circuits on a wall switch if you want table lamps controlled from the door.
We design and install layered lighting as part of every home renovation in London and every kitchen, and it works only if the daylight is right first. To plan lighting for your project, contact us or call 07472 424 226.