Case Study 09 · Domestic Lighting

LED Downlight Retrofit: 12 Dimmable on 2 Zones — Bath BA2

A Bath flat owner refurbishing for letting. Single-storey extension, single-day downlight retrofit, 12 LEDs split across 2 dimmable zones, MK Click Deco Plus chrome plates, 6+ year LED lifespan, BS 7671 + Part P paperwork in the inbox by 6 pm.

By Dan Stevens, Director · DS Electrical · 4 May 2026 · Q1 2026 install
NAPIT
Approved 66245
CHAS
Accredited 158368
2391
City & Guilds
TrustMark
Government Endorsed
Part P
Building Regulations
BS 7671
18th Edition Compliant

Generic case study. We do not name the owner, the address or the agent — the value is the survey, the zone split, the kit specification and the single-day work pattern that means the flat is ready for letting the next morning.

The brief

A Bath BA2 ground-floor flat (single-storey rear extension forming the open-plan kitchen-diner-living, two original front rooms used as bedroom and study). The owner had bought it as a refurb-and-let project. Existing lighting was a single pendant on a rose in each room — flat, low-output, undimmable, dated. The brief was: bring it up to a modern lettable standard with even, dimmable LED downlights in the open-plan extension and over-bed reading lighting in the bedroom, all in a single working day so the flat could go straight to the agent for photos the next morning.

What we did

Survey + zone design (morning of install)

12 LED dimmable downlights

MK Click Deco Plus chrome plates

Open-plan kitchen-diner with even LED downlight wash from a 4x3 grid of fittings
Open-plan kitchen-diner with the new 4×3 LED downlight grid — evenly lit, no dark spots, dimmable per zone.

The kit

ComponentSpec
Downlights12 × LED, IP65, fire-rated, 2700 K, CRI >90, 600–650 lm, dimmable, chrome bezel
Dimmer plateClick Scolmore Deco Plus screwless chrome 2-gang trailing-edge dimmer
Other accessoriesClick Scolmore Deco Plus screwless chrome (consistent across the flat)
Cable1.5 mm² T&E to existing lighting circuit, joist-drilled in extension void
ProtectionLighting circuit on existing Type A 30 mA RCBO at the board
LED lifespan6+ year manufacturer rating (~50,000 hours)
StandardsBS 7671 (18th Edition Amd 2), Part P notified via NAPIT

Single-day install — 7:30 in, 6 pm out

  1. 07:30 — Arrival, dust sheets, marking out. Floor and worktops covered, downlight grid marked on the ceiling with masking tape and pencil dots (laser level used to keep the grid square).
  2. 08:30 — Coring. 12 downlight cores drilled with a hole saw, dust extracted at source.
  3. 10:00 — Cabling. Lighting circuit extended from the existing pendant rose, looped through the 12 fittings on two zones, terminated back to the dimmer plate position.
  4. 12:30 — Lunch.
  5. 13:00 — Second fix. Downlights set, MK Click Deco Plus dimmer plate fitted, all other accessories in the flat upgraded to matching chrome.
  6. 15:30 — Test. Insulation, continuity, polarity, Zs, RCD trip time on the lighting circuit. Each zone tested independently across the full dim range.
  7. 17:00 — Cleardown. Cores vacuumed, dust sheets out, ceiling marks cleaned off, every fitting wiped down for the agent's photos.
  8. 18:00 — Paperwork. Minor Works Certificate, Part P notification, photos and VAT invoice in the owner's inbox before the agent's morning visit.

Result

Open-plan extension transformed from a single dim pendant to a modern, evenly lit, two-zone dimmable space — ready for the letting agent's photographer the next morning. Owner reported the photos came back significantly brighter and the flat let inside two weeks at the asking rent. Lighting load on the extension circuit dropped from a single 60 W incandescent pendant to 12 × ~7 W LEDs (84 W total at full brightness, typically run at 40–60% dimmed), giving lower running cost than the old fitting at full output and dramatically more usable light. No callbacks since handover — LED lifespan rated for 6+ years before any of the 12 fittings should need attention.

Who it's for

Bath flat owners and Mid Somerset homeowners refurbishing a property to let, prepping for sale, or simply tired of single-pendant rooms. Particularly suited to single-storey extensions and ground-floor flats where the ceiling void above is accessible and the work can be done in a single day without disrupting the rest of the building. Typical target rooms: open-plan kitchen-diners, lounges, master bedrooms, family bathrooms (bathroom downlights are zone-rated separately).

BS 7671 cert + Part P

Handover paperwork:

Why this approach. A single-day downlight retrofit only works if the survey is done in the first hour and the kit is on the van. Mark the grid square with a laser, split into two zones at the dimmer plate not at the board, keep the accessories consistent through the flat, and test before the dust sheets come out. Flat looks ready-to-photograph by 6 pm, paperwork by 7.

Also see: downlights, lighting design, Bath area.

About the figures. The room mix (open-plan extension + two original rooms), downlight count (12 in a 4×3 grid), zone split (2 zones at the dimmer plate) and single-working-day duration describe a representative reference job. Downlight retrofits are priced on a survey: ceiling fabric, void access from above, existing circuit capacity and accessory schedule all change the work. Indicative starting price for a comparable single-zone-or-two-zone retrofit in an accessible single-storey ceiling: from £680 all-in (12 dimmable LED fittings + Click Deco Plus chrome accessories + cert). All prices on the DS Electrical website and in our quotes are subject to VAT at the current rate (20%). DS Electrical Installations (SW) Ltd is VAT-registered (GB 429 0409 05).

Downlight retrofit on the cards?

Survey, zone design and accessory finish agreed before any kit is ordered. Single-day installs across Bath, Wells and Mid Somerset only.

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