LED Downlight Buying Guide: Fire Ratings, Colour Temperature & IP Ratings Explained

Downlights are the workhorse of modern home lighting. The difference between a great result and a disappointing one comes down to a handful of specifications most people never learn. This guide covers fire rating, colour temperature, brightness, IP rating and dimming.

Fire-rated or not? (Start here)

A downlight needs a hole in the ceiling. The hole breaks a fire barrier. A fire-rated downlight seals the hole during a fire and restores the ceiling's 30, 60 or 90-minute rating. UK Building Regulations require fire-rated fittings in most ceilings between floors of a dwelling.

Unless you know your ceiling needs no fire rating, choose fire-rated. The price difference is small. Browse our fire-rated downlight range.

Quick recommendations

• Best fire-rated, CCT-switchable downlight: 7W SMD Fire Rated Downlight IP44, 3CCT. Fire-rated as this guide recommends, with a switch to choose colour temperature at install.
• Best for a bathroom or wet zone: GU10 Holder Downlight IP65. Rated for bathroom zones where moisture resistance matters.
• Best budget standard downlight: GU10 Holder Downlight IP20. The simplest, lowest-cost option for a standard dry ceiling.
• Best decorative fitting: Kanlux MORTA B CT-DSO50 GU10 Ceiling Spotlight. A design-led fixture for a feature room.

Colour temperature: the number with the biggest effect

Measured in Kelvin (K), colour temperature decides whether a room feels cosy or clinical:

• 2700K to 3000K (warm white): living rooms, bedrooms and anywhere you relax
• 4000K (cool white): kitchens, bathrooms, utility and work areas
• 6000K and above (daylight): garages, workshops and commercial spaces

Many of our downlights are CCT switchable. A switch on the fitting sets the colour temperature at installation, so one product covers every room and reduces over-ordering.

Brightness: lumens, not watts

LED efficiency varies, so lumens tell you brightness. Wattage does not. As a rule of thumb for a 2.4m ceiling:

• General living space: one downlight per 1.2 to 1.5 m², around 400 to 500 lumens each
• Kitchen worktops and task areas: aim higher, 500 to 700 lumens per fitting

IP ratings: what you need where

• Bathrooms (zones 1 and 2, near showers and baths): IP65 rated fittings
• General bathroom areas: IP44 minimum is common practice
• Living areas: no IP requirement. Standard fittings suit.

Dimming

Not all LED downlights dim, and not all dimmers suit LEDs. Check the product page states dimmable. Pair the fitting with a trailing-edge LED dimmer for flicker-free performance. Mixing dimmable and non-dimmable fittings on one circuit is a common cause of flicker callbacks.

Recessed or surface-mounted

No ceiling void? A concrete soffit? Prefer the look? Surface-mounted downlights give the same light without cutting in. For everything else, recessed remains the cleanest finish. See the full downlight collection.

Trade electrician?

Vertex Supplies stocks Integral LED, Ener-J and Kanlux downlights at trade-friendly prices with fast UK delivery from Bradford. Register for a trade account or call 01274 955353 for bulk pricing on larger jobs.