Choose a mains rooflight when the ceiling is open and an electrician can reach it, because unlimited cycles cost nothing to run. Choose solar on a retrofit into a finished room, where a cable route means lifting floors or chasing walls. Build stage decides it, not the technology. Solar costs roughly £150 to £200 more supplied and fitted.
That is the short version and it holds for most of the jobs we survey around Ipswich. The longer version matters when your case sits near the boundary: a north-facing unit, a household that cycles the vent four times a day, or an extension where the electrician is already on site but the run is 18 metres of awkward joist.
Mains vs solar rooflight: the differences that actually bite
Both types use the same chain actuator, the same rain sensor and usually the same 868MHz handset. The mechanism is not the variable. Where the power comes from is.
| Aspect | Mains powered | Solar powered |
|---|---|---|
| Operating cycles | Unlimited, year round | Plentiful in summer, reduced in December and January |
| Behaviour in a power cut | Fails safe in position, cannot be driven | Unaffected, carries its own battery |
| Electrician needed | Yes, for everything up to the fused spur | No fixed mains connection at all |
| Disruption on a finished room | Lifted floors, chased walls or surface trunking | None inside the room |
| Consumable parts | None | Battery, roughly eight to twelve years |
| Like-for-like replacement roof window | £1,600 to £2,300 | £1,750 to £2,500 |
| Electrical connection on top | £180 to £400 open ceiling, £350 to £900 finished room | Nil |
| Suits AOV smoke ventilation | Yes, with a control panel and battery backup | No, current draw is too high |
Reliability, and which one fails first
Neither type fails in a way the other avoids. Actuators wear out, gaskets harden, control boards get damp. The difference is in the failure modes each one adds.
A mains unit adds the supply. A tripped RCD, a nuisance trip on a shared lighting circuit, or a spur that was never labelled and got isolated during other work will all present as a dead rooflight. It fails safe in whatever position it was in and cannot be driven until the power is back, which is only a problem if it happened to be open. Our power cut page sets out the three answers to that.
A solar unit adds a battery and a panel. Batteries lose capacity gradually rather than failing outright, so what you notice at year ten is not a dead unit but a sluggish one that runs out of cycles by mid-afternoon in February. Panels lose output to salt film and to leaf litter, both of which are cleaning problems rather than faults.
On the coast at Felixstowe or Aldeburgh, the solar unit has a quiet advantage worth stating: fewer cable entries through the frame means fewer routes for damp salt air to reach a connector block. The panel and the rain sensor pad both need a fresh water rinse twice a year, which is the same visit.
Solar in a Suffolk winter, honestly
Ipswich sees roughly 45 to 55 hours of bright sunshine across the whole of December, and daylight itself runs about eight hours a day. That sounds fatal for a solar rooflight and it is not, because modern panels charge from overcast daylight rather than from direct sun. Flat grey Suffolk light still produces charge.
The realistic midwinter outcome is fewer operating cycles per day, not a dead unit. You get a handful of open and close cycles rather than unlimited use. The rain sensor draws so little current that it keeps working throughout, so the unit still shuts itself when the weather turns even when you have used up your cycles.
Where it goes marginal is specific and worth checking before you order:
- North-facing slope. Less diffuse light reaching the panel across the whole winter, not just on dull days.
- Shading. A chimney stack, a neighbouring roof or a mature tree over the panel. Shade in December costs proportionally far more than shade in June.
- Heavy daily use. A kitchen vent opened and closed four or five times a day in January is the one case where we will steer you towards mains if a route exists.
A south, east or west facing unit with clear sky above it, used normally, is a non-issue. We check orientation and shading in person at survey and say plainly if it is borderline rather than letting you find out in January.
Batteries are replaceable, and they are a cost you should plan for. Expect service life in the region of eight to twelve years. That is a consumable, not a failure, and it does not make solar the worse buy. It makes solar a buy with a known future line item that a mains unit does not have.
The decision rule, by build stage
This is how we advise at survey, and it decides the great majority of jobs before any of the winter arithmetic comes into it.
- New extension, ceiling open, electrician on site. Mains. The connection costs £180 to £400 at first fix, you get unlimited cycles for the life of the unit, and there is no battery to replace. This is the easy case.
- Loft conversion in progress. Mains, for the same reason, and it is worth running the cable even if you fit a manual unit now.
- Retrofit into a finished, decorated room. Solar, nearly always. The £150 to £200 premium on the unit is less than the £350 to £900 the cable route costs, and it buys you no lifted floors and no redecorating.
- Existing manual roof window of the right generation. Check for a solar conversion kit first. £520 to £850 and half a day, without touching the roof covering. Photograph the data plate on the top edge of the sash.
- AOV smoke ventilation. Mains, always, with a control panel and battery backup. Solar is not an option for life-safety ventilation.
- Anywhere the vent is over a stairwell or a room you cannot easily reach. Mains with battery backup, so the unit can drive itself closed at least once when the power goes.
One thing that is not a tiebreaker: running cost. An electric rooflight draws power for 30 to 60 seconds per cycle. Neither option has a meaningful energy bill attached.
Can a solar rooflight be converted to mains later?
Some models accept a supplementary mains charge if a supply becomes available, and it is worth specifying that capability at order if you might extend a circuit into the room one day. Most cannot be converted after the fact. If there is a realistic chance of the ceiling coming down within a few years, say so at survey and we will specify accordingly.
Is a solar rooflight less powerful than a mains one?
The actuator itself is the same class of chain unit, with a stroke of 200 to 500mm and a closing force of 200 to 300 newtons, so the sash opens the same distance and seals the same way. What differs is how many times a day it can do it in midwinter. Hinge and spindle actuators, used on AOV work and on large exposed units, are rarely available in solar versions because the current draw is too high.
Get it decided at survey
Read the full picture on our electric skylight installation page, or go deeper on either option: solar powered rooflight installation and the electrical side of an electric rooflight installation. If cabling is the sticking point, how you get power to a rooflight covers the routes, and why solar suits retrofit projects covers the other side.
We walk the cable route before we price anything, and where there is no honest route we price a solar unit alongside the mains one so you can compare properly. Every installation carries a 10-year workmanship guarantee.
Request a fixed quote and tell us the room, the roof type and roughly where the property sits.
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.