Replace an electric rooflight when the control system is no longer supported, when the actuator has failed more than once, when water tracks in at the sash in driven rain, when the sealed unit has misted, or when coastal fixings and brackets have corroded. Any one of those means the unit is at the end of its working life.
Most people arrive at that conclusion the long way round, usually after paying twice for a part that was never the real problem. An electric rooflight is a frame, a sealed glazing unit, a moving sash on a gasket, and a mechanism with electronics attached. Those parts do not wear out together, but they do wear out in a sequence, and once the second one goes the third is generally not far behind.
We are skylight installers. We survey, we diagnose honestly, and then we replace. We do not repair, reseal or patch, so nothing below is written to sell you a part.
The five triggers
1. Unsupported controls
The commonest one, and the least expected. Radio control systems have a life measured in product generations rather than years. When a manufacturer retires a protocol, the handsets, the receivers and the wall switches stop being made, and a paired system with a dead receiver cannot be re-paired to anything current. There is no adapter. You are not looking at a broken rooflight, you are looking at a working rooflight you can no longer operate, which amounts to the same thing at ceiling height. Our page on obsolete electric rooflight controls sets out how to identify what you have from the data plate.
2. Repeated actuator failure
A chain actuator that fails once at fifteen years old has done its job. The same actuator failing a second time inside two or three years is telling you something else: the sash is binding, the frame has moved, or the gasket has hardened enough that the motor is working against 300 newtons of resistance every time it closes. Replacing the mechanism again treats the symptom. If you want the mechanics behind that, why electric rooflight motors stop working covers the failure modes in detail.
3. Water ingress at the sash
Water at the flashing or the upstand is a weathering problem. Water appearing along the sash line, inside the opening, when the unit is shut and it is blowing hard from the east, is a seal problem, and seals are not serviceable items on a sealed opening unit. A hardened gasket no longer recovers its shape after the actuator compresses it. Once that has happened the unit will pass a still-day hose test and leak in a February gale, which is exactly the pattern people describe to us.
4. Misted glazing
Condensation between the panes means the edge seal of the sealed unit has failed and the cavity gas has gone. The visible misting is the least of it. The unit is now performing nowhere near its stated U-value, which matters under Part L, where a replacement rooflight in an existing dwelling has to achieve 2.2 W/m²K or better across the whole unit. On many electric rooflights the glazing is bonded into the sash rather than beaded in, so the sealed unit is not independently replaceable. Where it is, the cost of the glass plus the access usually lands close enough to a new unit that the ten-year guarantee decides it.
5. Corroded coastal fixings
Within about a mile of open sea at Felixstowe, Harwich, Frinton, Aldeburgh or Southwold, chloride pitting attacks fixings and actuator brackets specified for inland conditions. Grade 304 stainless is the usual culprit; it lacks the molybdenum content that resists chloride attack, and it stains within two or three winters. A seized fixing head or a pitted bracket is not a cosmetic issue, because the bracket is what holds the mechanism in alignment. We fit 316L throughout on coastal work. Estuarine properties at Woodbridge, Wivenhoe, Manningtree and Pin Mill carry moderate salt loading rather than open-sea exposure, and upgraded fixings there are sensible rather than essential.
| What you see | What it usually is | Realistic outcome |
|---|---|---|
| Handset does nothing, unit has power | Failed or unsupported receiver | Replace if the protocol is retired |
| Second actuator failure in three years | Sash binding or hardened gasket | Replace the unit, not the mechanism |
| Damp along the sash in driven rain only | Gasket no longer recovering | Replace |
| Mist between the panes | Failed edge seal, gas lost | Replace, Part L applies |
| Rust staining at bracket and fixings | Grade 304 stainless on a coastal roof | Replace with 316L throughout |
| Rain sensor closing on dry days | Salt or pollen film on the pad | Clean first, this one is often not a fault |
Stay off the roof. None of these checks needs you on a roof, on a flat roof surface, or forcing a sash by hand. If a unit is stuck open in the rain, isolate it at the fused spur, protect the room below and read rooflight stuck open in the rain.
Age, and what it fairly predicts
An electric roof window fitted in the mid 2000s is on borrowed time for control availability regardless of how well the mechanism runs. Sealed units commonly start misting somewhere between fifteen and twenty-five years, earlier on a south-facing slope where the glass cycles through a wider temperature range daily. Actuators outlast both, which is why so many failures present as electrical when the real fault is the weathering.
One thing genuinely worth checking before you write a unit off: some manual roof windows of the right generation take a solar conversion kit, £520 to £850 fitted and half a day on site. That does not rescue a failed electric unit, but if the misted one next to it is manual, it changes the plan.
Your replacement checklist
- Find the data plate on the top edge of the sash and photograph it. Model and year decide whether controls are still available.
- Confirm the unit has power at the fused spur before assuming the mechanism is dead.
- Clean the rain sensor pad with fresh water. Twice a year on the coast. A surprising number of faults end here.
- Count actuator failures. Two in three years means the sash, not the motor.
- Look along the sash line for staining, and note whether damp only appears in wind-driven rain.
- Check the glazing for misting from inside, in flat daylight rather than sunshine.
- On a coastal property, look for rust staining at the visible fixings and brackets.
- Note your roof type and whether there is loft access above, which decides the cabling route on a mains replacement.
- Compare against a like-for-like replacement at £1,600 to £2,300 fitted before spending anything further.
Three or more ticks and the unit is at the end of its life. Read what an electric rooflight costs to install for the full picture, or retrofitting a motor versus replacing if the frame itself is sound. The hub page on electric skylight installation covers the specification decisions you will face next.
Get it surveyed properly
Send us the data plate photograph, the room, the roof type and roughly where the property sits. We survey the unit, the opening and the cable route, then give you one written price that is fixed. Every installation carries a 10-year workmanship guarantee, and the installers have 25 years fitting rooflights behind them.
Request a fixed quote for a replacement electric rooflight in Ipswich, Suffolk or north Essex.
Thinking about this job? We survey across Ipswich, Suffolk and north Essex and give you a fixed price before any work starts, with a 10-year workmanship guarantee.