Lighting FAQs
Answers to frequently asked questions about LED downlights, fire-rated fittings, dimming, colour temperature, and lighting installation requirements.
1
What is the difference between LED and halogen downlights?
LED downlights use up to 90% less energy than halogen equivalents, last 25,000-50,000 hours versus 2,000 hours for halogen, and produce significantly less heat. While LEDs have a higher upfront cost, they save substantially on energy bills and replacement costs over their lifespan, making them the preferred choice for virtually all new installations.
2
Do I need fire-rated downlights?
Yes, fire-rated downlights are required when installing into ceilings that form a fire barrier, which includes most domestic ceilings between floors. They maintain the fire resistance of the ceiling for 30, 60, or 90 minutes depending on the rating. UK Building Regulations require fire-rated downlights in most residential and commercial installations. Non-fire-rated downlights are only suitable for ceilings without a fire barrier requirement, such as ground floor ceilings with no room above.
3
What colour temperature should I choose?
Colour temperature is measured in Kelvin (K). Warm white (2700K-3000K) creates a cosy, relaxing atmosphere ideal for living rooms and bedrooms. Cool white (4000K) provides a bright, clean light suitable for kitchens and bathrooms. Daylight (5000K-6500K) is used in commercial settings, garages, and task lighting where maximum clarity is needed. Many modern LEDs offer adjustable colour temperature (CCT) so you can switch between settings.
4
What size hole do I need to cut for downlights?
Standard downlight cut-out sizes are typically 65mm, 70mm, or 85mm in diameter, depending on the fitting. Always check the product specification before cutting. The cut-out size must be accurate for a secure fit and to maintain fire rating integrity on fire-rated models. Some adjustable downlights accommodate a range of existing cut-out sizes, making them ideal for retrofit projects.
5
Can I dim LED downlights?
Yes, but only if the LED is marked as dimmable and you use a compatible LED dimmer switch. Trailing-edge (electronic) dimmers are recommended for LED lighting. Check the dimmer switch specifications for minimum and maximum wattage ratings, and ensure the total LED load falls within these limits. Using an incompatible dimmer can cause flickering, buzzing, or limited dimming range.
6
What IP rating do I need for bathroom lighting?
Bathroom lighting must meet specific IP ratings based on the zone. Zone 0 (inside the bath/shower) requires IP67. Zone 1 (above the bath/shower to 2.25m) requires IP44 minimum, though IP65 is recommended. Zone 2 (0.6m around the bath/shower) requires IP44 minimum. Outside zones have no specific IP requirement, but IP44 is good practice. All bathroom lighting work must comply with BS 7671.
7
What is a driver and do I need one for LED lighting?
An LED driver converts mains voltage (240V AC) to the low voltage (typically 12V or 24V DC) required by LED lights. Integrated LED downlights have a built-in driver, so no separate driver is needed. LED strip lighting and some commercial fittings require a separate driver. Ensure the driver wattage is sufficient for the total LED load, and use a dimmable driver if dimming is required.
8
How many downlights do I need per room?
A general guide is one downlight per 1.2 to 1.5 square metres of floor space. For a 4m x 4m room (16 sqm), you would typically need 10-12 downlights. Space them evenly, keeping at least 500mm from walls. The exact number depends on the lumen output of each fitting, ceiling height, and the desired light level. Kitchens and workspaces may need more, while bedrooms may need fewer.
9
What is the difference between fixed and adjustable downlights?
Fixed downlights project light straight down and are ideal for general ambient lighting. Adjustable (tilt) downlights can be angled to direct light onto specific features, artwork, or work surfaces. Adjustable models typically tilt 20-35 degrees from vertical. Choose fixed for uniform general lighting and adjustable for accent or task lighting where directional control is needed.
10
Do I need a qualified electrician to install downlights?
Yes. Installing downlights involves cutting into ceilings, running cables, and connecting to mains circuits, which constitutes notifiable electrical work under Part P of UK Building Regulations. A qualified electrician (registered with NICEIC, NAPIT, or similar scheme) must carry out the work to ensure safety, compliance, and that fire-rated integrity is maintained.