Summary
Downlight installation has become the default lighting upgrade in UK homes — replacing the central pendant in every room with a grid of 50–80mm-diameter LED downlights. Customers see them in TV property programmes and assume they're a Sunday afternoon job. The reality, particularly in occupied homes with finished ceilings, is that downlight installs are time-consuming, dust-generating, and pricing-sensitive in ways that aren't always obvious to the customer.
The cost drivers split into three: (1) the lights themselves (£8–£40 per fitting trade, £25–£80 customer), (2) the wiring (fast in a stripped-back loft, slow under upstairs floorboards), and (3) the fire-rating compliance (a downlight punched through a fire-rated ceiling without a fire hood is a Building Regulations breach that may also void building insurance). Tradespeople who quote per light without checking the ceiling construction get caught when the loft access reveals a compartment floor between flats — a £40-per-light job becomes a £100-per-light job.
This article gives the per-light and per-room pricing logic, the fire/IP/cable selection rules from BS 7671 and Approved Document B, and the install sequence. Pricing per-light + per-visit setup fee + cost of any required additional works (new circuit, switching upgrades, holes through fire-rated layers) gives the customer an honest breakdown they can compare across quotes.
Key Facts
- Primary electrical standard — BS 7671:2018+A2:2022 (the IET Wiring Regulations)
- Notification — Approved Document P; new circuits notifiable; bathroom downlights notifiable
- Fire safety standard — Approved Document B (fire safety); BS 476-21 / BS EN 1364 (fire-resistance test)
- Fire-rated downlights — Required where downlights penetrate floor/ceiling separating dwellings, compartments, or escape routes; typically 30/60/90/120 minute fire-rated hoods or integrated fittings
- Bathroom zones (BS 7671) — Zone 0 (inside the bath/shower): IPX7 minimum, SELV 12V or 50V AC max; Zone 1 (above bath/shower to 2.25m): IPX4 minimum; Zone 2 (0.6m beyond bath/shower to 2.25m): IPX4 minimum
- IP rating for kitchen splashback area — Typically IP44 for downlights within 1.2m of a sink
- Loft insulation interaction — Old halogen downlights required insulation to be cut back (fire risk); modern fire-rated LED downlights can have insulation laid over (check manufacturer's specific approval)
- Standard downlight sizes — 50mm, 65mm, 80mm cutout (smaller = more delicate fit; 65mm is the modern default)
- Beam angle — 36° wide / 24° narrow / 12° spot; choice affects spacing (wide for general illumination, narrow for accent)
- Spacing rule of thumb — Centre-to-centre = ceiling height for wide-beam general lighting; closer for accent or task lighting
- Driver location — Integrated (in fitting, easiest), in junction box above ceiling (serviceable), remote with leads (for low-voltage transformers)
- Cable — 1.0mm² or 1.5mm² T&E to BS 6004 / BS 7211; LSF/LSZH cable required in some commercial applications (BS EN 50525)
- Switching — Standard MK or similar 1-gang/2-gang switch; dimmer-compatible LED downlights need a compatible dimmer (leading-edge vs trailing-edge)
Quick Reference Table
Spending too long on quotes? squote turns a 2-minute voice recording into a professional quote.
Try squote free →| Job Type | Per-Light Customer Price | Per-Room Indicative |
|---|---|---|
| Replace existing downlights (like-for-like) | £35–£60 | n/a |
| New downlights, accessible loft, standard ceiling | £40–£75 | £200–£500 (5 lights) |
| New downlights, upstairs (no loft, board lift) | £80–£140 | £400–£800 (5 lights) |
| New downlights, fire-rated ceiling (flat/compartment) | £75–£130 | £450–£900 (5 lights) |
| New downlights, bathroom (Part P notifiable) | £80–£160 | £400–£800 (4 lights) |
| Kitchen, 8–10 lights, 1-gang dimmer, accessible loft | n/a | £550–£1,100 |
| Open-plan ground floor 15+ lights, 2-circuit | n/a | £950–£1,800 |
| Whole-house downlight install (3 bed, 35 lights) | n/a | £2,400–£4,500 |
| Component | Trade Cost |
|---|---|
| LED downlight, standard fire-rated, 65mm | £12–£25 |
| Premium fire-rated LED (Aurora, Collingwood, JCC) | £25–£50 |
| GU10 LED lamp (4-7W, replaceable) | £4–£10 |
| Integral LED (non-replaceable) — full unit | £18–£60 |
| 1.5mm² T&E cable per m | £1.20–£2.00 |
| Junction box (BS 5733 maintenance-free) | £3–£8 |
| Compatible dimmer switch | £18–£45 |
| 1-gang plate switch | £5–£15 |
| Fire hood for retrofit | £8–£20 each |
| Variable | Effect on Price |
|---|---|
| Fire-rated ceiling penetration | +£10–£30 per light (fire hood + extra labour) |
| Bathroom install (Part P notification) | +£15–£40 per light (admin + certificate) |
| New circuit run to CU | +£150–£350 (one new MCB, new T&E run) |
| Plaster reinstatement at downlight cuts | Typically minimal if neat; +£20–£60 if filler/redec needed |
| Customer-specified premium downlight | per fitting cost difference passed on |
| Smart/dimmable controls (Lutron, Crestron) | Quote separately as control system |
| Stainless / chrome / brushed-nickel finish | +£5–£15 per fitting over standard white |
Detailed Guidance
The Pricing Logic
Build the price from:
- Per-light fee for the standard install (cut hole, run cable, fit, test). This is the base unit. £40–£75 in standard work.
- Per-visit setup fee for vehicle, tools, dust sheets, vacuum, hand-over. £40–£100.
- Additional works — new circuit, dimmer swap, fire hoods, plaster reinstatement, ceiling repair. Itemised separately so the customer can see what they're paying for.
- Certification — Minor Works Certificate for additions; Electrical Installation Certificate for new circuits. Building Control notification fee where applicable.
A 4-light kitchen install on an accessible loft ceiling: 4 × £50 + £80 setup + £40 controls = £320 trade. Add markup and VAT. £400–£500 customer price.
The same 4 lights in a downstairs ceiling with no loft above (need to lift upstairs floorboards to run cables): 4 × £100 + £80 setup + £40 controls + £100 floorboard make-good = £620 trade. £750–£900 customer price.
Walk the customer through the difference. The £750 quote vs the £400 quote isn't a different trade ripping them off — it's the difference between an accessible install and a finished-floor install.
Fire-Rated Downlights — When and Why
Approved Document B requires fire-resistance in floor/ceiling assemblies separating:
- Dwellings (flats above/below each other)
- Compartments (commercial fire compartments)
- Escape routes (corridors below bedrooms in HMOs)
The ceiling's required fire-resistance period (typically 30 or 60 minutes for domestic, up to 120 minutes in commercial) must be maintained at every penetration. A downlight cut into a 30-minute fire-rated ceiling creates a hole; the fire-rated downlight (or a separate fire hood over a standard downlight) restores the fire-resistance.
In a single-family house: ground-floor downlights into the upstairs floor void are NOT through a fire-separating element — Approved Document B does not require fire-rated fittings here. Use of fire-rated fittings is a quality choice in this case (better acoustic performance, future-proof if the house is ever converted to flats).
In a flat: the floor between flats IS a fire-separating element — fire-rated downlights mandatory.
In a converted Victorian house with HMO licence: the floor/ceiling between bedrooms and the escape stairwell IS a fire-separating element — fire-rated mandatory.
Always check the building before specifying. A "we just need downlights in the lounge" job in a converted flat is a different job from the same in a freehold semi.
IP Rating in Bathrooms
BS 7671 specifies minimum IP ratings by zone:
- Zone 0 (inside the bath or shower basin): IPX7 minimum, SELV 12V or 50V AC limit
- Zone 1 (above Zone 0 to 2.25m): IPX4 minimum
- Zone 2 (0.6m beyond bath/shower to 2.25m): IPX4 minimum
- Outside zones in the bathroom: standard IP rating, with RCD protection mandatory
In practice for bathroom downlights: IP65 fire-rated LED downlights are universal — they suit all zones and avoid the complication of zone-by-zone specification. Cost is slightly higher (£20–£40 each trade) but cuts out a category of error.
Cable Routing — The Big Time Variable
Downlight install productivity is dictated by access:
- Loft above the room (typical ground-floor downlights in a 2-storey house with cold loft): fastest — drill holes, drop in light, connect cable in loft. 30–45 min per light.
- Voids above ceiling (downstairs with a habitable room above): cable runs from a switched point at a wall, across the wall to a stud cavity, up to the ceiling, then through the floor void from one stud cavity to the next via drilled joists. 45–90 min per light.
- Finished ceiling, no access (upstairs room with a finished loft, e.g. loft conversion): cable runs back to a switch point via a chase in the wall or a careful surface clip in a wardrobe; new joist holes drilled from below; existing pipework/cables avoided. 60–120 min per light.
Survey the access route before quoting. A blocked loft hatch, a finished loft conversion, or solid concrete first-floor construction can move a job from £40/light to £120/light.
Insulation Interaction
Modern LED fire-rated downlights are typically rated for direct insulation contact (no airgap required), but this is a manufacturer-specific certification — check the datasheet. Older designs (and most halogen downlights) required a 100–150mm air gap above the fitting with insulation cut back, both for thermal management and fire safety.
If you're installing into an insulated loft, the choice is either (a) modern direct-contact fire-rated LED downlights, or (b) standard downlights with formal insulation cut-backs and the resulting heat loss. Option (a) is the only sensible answer in 2026.
For Approved Document L compliance, the SAP/SBEM calculation for the dwelling treats downlight cut-backs as thermal bridges; cumulative effect on a whole-house downlight install can be significant.
Switching and Dimming
LED downlights need a compatible dimmer. Three pitfalls:
- Standard pre-LED dimmer with LED lights — flickers, hums, or refuses to dim. Replace with LED-compatible dimmer.
- Leading-edge dimmer with trailing-edge LED (or vice versa) — same symptoms. Match the dimmer type to the lamp driver type per manufacturer specification.
- Mixed dimmer + non-dimmable LED lamps — the non-dimmables blow within hours. Confirm all lamps in the circuit are dimmable.
A typical job specifies a Varilight V-Pro or similar LED-compatible dimmer (£18–£45) matched to integral-driver LED downlights of the same brand wherever possible. £15 per dimmer position in the cost.
Worked Example: Kitchen Downlight Install
Job: 4 × 65mm fire-rated LED downlights in a kitchen ceiling. Cold loft above; existing pendant on a 1-gang switch to be replaced with a LED dimmer. Customer arranging painting separately.
| Item | Cost |
|---|---|
| 4× Collingwood H4 Fire-Rated LED IP65 65mm | £88 |
| Varilight V-Pro Trailing-Edge dimmer | £30 |
| 12m T&E 1.5mm² | £18 |
| 4× junction boxes BS 5733 | £18 |
| Fixings, terminal blocks, cable clips | £15 |
| Materials subtotal | £169 |
| Labour 4.5 hours @ £55/hr | £248 |
| Setup, dust sheets, vacuum | £40 |
| Test, certificate, hand-over | £35 |
| Labour subtotal | £323 |
| Subtotal | £492 |
| Markup 20% | £98 |
| Net price | £590 |
| VAT 20% (if registered) | £118 |
| Customer price (VAT-reg) | £708 |
A non-VAT-reg sole trader would land at £590. In real markets this 4-light job competes against £400 (no loft access surcharge, cheaper lamps) and £900 (full system upgrade including new circuit). The honest quote sits in the middle.
Frequently Asked Questions
How many downlights do I need for a kitchen?
Rule of thumb: ceiling area in m² × 4–6 = lumens required, then divide by lumens per fitting. A 12m² kitchen at 400 lumens/m² needs 4,800 lumens; at 500 lumens per LED fitting that's roughly 10 lights. But practical layouts also consider task lighting over worktop, accent over island, and visual grid — most customers prefer 6–10 in a typical kitchen rather than 10–12 packed in.
Should I use mains-voltage or low-voltage downlights?
Mains-voltage GU10 LED downlights are the default in modern UK installs — they're simpler (no transformer), more readily replaceable lamps, and cheaper. Low-voltage (MR16 with transformer) was the standard in the halogen era but is now reserved for specific applications (decorative pendant transformers, certain feature lighting). For 95% of jobs, mains-voltage GU10 LED or integral-driver LED is the answer.
Can I retrofit fire hoods over my existing downlights?
Yes — fire hoods (intumescent cap that fits over the downlight body in the ceiling void) bring an existing non-fire-rated downlight up to fire-rated performance. Cost £8–£20 each. Useful in flat conversions where the existing downlights are non-compliant; the alternative is full downlight replacement.
How long do LED downlights last?
Manufacturer claims of 25,000–50,000 hours are common; in practice domestic use (3 hours/day average) gives 10–20 year life on quality fittings. Driver failure usually before lamp failure — buy fittings where the driver is serviceable (replaceable separately) rather than fully sealed throwaway units.
Do I need to notify Building Control to fit downlights?
Only if the work is in a bathroom (special location, always notifiable under Part P) or involves a new circuit. Adding downlights to an existing circuit in a non-bathroom room is not notifiable, though a Minor Works Certificate is best practice for record purposes. Notifiable work requires a registered installer (NICEIC / NAPIT etc.) or Building Control approval.
Regulations & Standards
BS 7671:2018+A2:2022 — IET Wiring Regulations
Approved Document P — Building Regulations Part P (electrical safety, notification)
Approved Document B — Building Regulations Part B (fire safety, including downlight penetrations in compartment floors)
Approved Document L — Building Regulations Part L (energy efficiency); fixed-internal lighting efficiency requirements
BS EN 60598-1 — Luminaires — General requirements and tests
BS EN 60598-2-2 — Luminaires — Particular requirements: Recessed luminaires
BS 476-21 — Fire tests on building materials and structures (fire-resistance test method)
BS EN 1364 — Fire resistance tests for non-loadbearing elements
BS EN 60529 — Degrees of protection provided by enclosures (IP code)
BS 5733 — General requirements for electrical accessories (junction box standard)
Aurora Lighting technical guide — Major UK downlight manufacturer
Collingwood Lighting — Fire-rated specialist
Approved Document P — Building Regulations Part P
Approved Document B — Building Regulations Part B
bathroom zones — Bathroom zone classification
lighting controls — Switching and dimming options
spur vs radial vs ring final — Circuit selection for new lighting circuits
internal wall insulation — Insulation-downlight interactions