Electric and Opening Rooflight Installation in Bristol A roof that opens at the press of a button

Three kinds of opening are on offer. A manual unit has a handle or a pole and costs least. A mains-powered electric unit is wired to the house and gives the strongest, most predictable movement. A solar unit charges a small battery from daylight and needs no cable to the house at all. All three can carry a rain sensor, though on a manual unit the sensor has nothing to close. The page on electric vs solar rooflight choices sets the two powered kinds side by side for a real house.

What the VELUX range calls it

VELUX groups its electric and solar units under the INTEGRA name. They arrive with a motor, a control pad and a rain sensor already in the box, and the control pad can run blinds and shutters from the same remote. Other leading makers have comparable ranges, and we quote from more than one so that you can see the choice laid out. Nothing here depends on a single brand.

Not every rooflight can be powered. Some designs open by a top hinge, some pivot on a centre bar, and some are fixed in the roof by design. A flat rooflight over a flat roof lifts from a hinged side or slides back over a fixed pane, and each style has its own motor arrangement. We check which style you already have, or which style suits the opening you want, at the survey.

What follows takes the subject in the order a homeowner meets it: how the sensor and the controls behave, what the wiring involves, whether an old unit can be converted, where opening earns its keep, and what sits behind the quote.

Controls you can live with

The best control is the one the household actually uses. A wall switch beside the stair suits a landing unit, since you pass it every day. A handheld remote suits a loft bedroom, where it lives on the bedside table. Some systems also link to a smartphone or a smart-home hub, which is handy for closing everything from the sofa. The common thread is a close button that is easy to find in a hurry.

Leaving it open at night

Many people ask whether a rooflight can safely stay open overnight. The answer is that it can be set to a narrow gap on a vent bar, which lets stale air leave while the sash stays close to the frame. A fully lifted sash is a different matter, as it is a wide opening in your roof while you sleep, and a rain sensor is no help if the power fails. The detail is in the answer on whether to leave a rooflight open overnight, and our advice there is plain: use the narrow setting, and close the sash fully when you go out.

Wind is the other matter. A sash lifted fully open on a gusty day behaves like a sail. Good units are built to hold against ordinary wind, and the stay or the motor arm carries the load, but it is sensible to close any opening rooflight in a gale. Some wired systems include a wind sensor as an extra, and it goes on the quote as an extra when a roof is exposed, such as on the open edge of a hill estate.

The position of the sensor also matters on a flat roof, where puddles and falling leaves can keep the contacts wet or blocked. We place it so rain reaches it freely and debris does not sit on it, and we show you how to wipe it clean with a damp cloth.

How the cable goes in

1. At the survey, we mark where the switch will sit and the route the cable could take.
2. On a new opening, the cable is run to the frame before the ceiling is closed.
3. The motor is fitted to the sash or the frame and connected to the control unit.
4. The electrician connects the supply and tests the circuit.
5. The unit is set up, the limits are programmed and the rain sensor is tried with a damp cloth.

Convert or replace

Replacing gives you more than a motor. The new frame is insulated to current standards, the flashing is renewed and the glass is modern. An old unit may have lost its seal, and if the glass has clouded, a new sealed unit is the sensible move. The case for swapping a clouded unit is made on the misted and failed rooflights page.

Roof windows with a different history

Roof windows fitted in a 1980s or 1990s loft conversion often have timber frames, and some have a pole hook on the sash. They were made well, and some have lasted for decades. Those are the units where owners ask about a motor, because the loft room is now a bedroom and the pole is a nuisance. Where the frame is sound, a new sash and glazing unit is sometimes available for the same frame, and where it is not, a new unit goes in the same opening with the least disturbance, as the roof structure is already trimmed.

If the opening is changing size, perhaps going wider to give more air, it counts as a new opening and the roof structure needs trimming properly. We measure for that at the survey and show the options on the quote. A first look costs you nothing, and you have the choice between converting, replacing and leaving things as they are, all written down with the prices beside them.

Whatever we recommend, the opening options appear on every quote, so you can compare a motorised version with a manual one before deciding. Our page on roof windows covers the wider range if you would like to look at fixed and manual types as well.

Where opening helps

A bathroom or shower room under the roof is the clearest case. Steam rises to the ceiling and condenses on cold surfaces. An opening rooflight above the shower lets that steam leave, and it can help condensation clear, though it works best alongside an extractor fan. A stair landing in a three-storey Georgian house in Clifton or Bath is the next. The stairwell acts as a chimney, and an opening unit at the top lets the warm air out while windows lower down let cooler air in. A loft bedroom is the third, since the room is warmest at night just where the sleeper wants cool air.

A kitchen extension with a flat rooflight over the cooker or the island is the fourth. Cooking heat and smells rise and leave through an opening unit. Part F, the ventilation regulation, lets an opening roof window count for the rapid airing a room needs to clear smells and moisture.

Where fixed is better

A fixed rooflight suits a room with plenty of opening windows already. It is cheaper, it has no moving parts, and the frame is slim. A hallway or a walk-in wardrobe with no heat or steam gains little from a motor. A walk-on rooflight in a floor or terrace is always fixed, and our page on walk-on rooflights covers those. A rooflight in a very sheltered corner might be fixed too, as the occupants do not need air from that point.

The other time fixed wins is a listed or conservation-area roof where a bulky actuator would spoil the look of a slim conservation-style unit. Much of Bath sits inside its World Heritage setting and a conservation area, and Clifton and Kingsdown in Bristol have their own protected streets. Our conservation rooflights page deals with the slim, flush units used there.

Houses where we fit them

Terraces in Totterdown and Bedminster have a landing rooflight above the stairs and a loft room beyond it. Bath's Georgian terraces have a tall stairwell and often a rooflight at the very top. In Bath, listed building consent and conservation-area rules are the first question. On 1930s semis in Keynsham, loft conversions are common and a motor above the landing suits the stairs. In a bungalow with rooms in the roof, the unit can double as the way out in a fire, where the regulations allow.

The page on fresh air rooflights gives the wider case for opening, and our flat roof rooflights page covers the extension side. Fixed or opening, both go on the quote so you can see what the motor adds.

Energy figures

The energy rules treat the two products differently: a roof window must meet the usual window figure, while a flat rooflight has a looser limit of its own. Our page on energy-efficient rooflights gives the exact numbers, and fitting a motor changes none of them. Electric units run on very little power, so running costs are small, and the more important question is whether the glass is good.

Rules around the work

Taking out a whole unit and fitting a new one needs a Building Control notification. Replacing only the sealed glass unit in an existing frame generally is not. A new opening in a roof is building work too, and the structure must be trimmed properly. Where the work is notifiable, we send the notification ourselves and pass you the certificate afterwards.

Planning is usually simple. In England, Class C permitted development means rooflights usually need no planning permission if they stand clear of the slope by 150mm at most and sit below the ridge line. Side-facing units need obscure glass and must not open unless the opening part is more than 1.7m above the floor. Those rights stop at the front door of a flat. A listed house needs consent from the council before any roof work, and some protected streets lose the rights altogether, so ask before you book. The Planning Portal has the national guidance.

The visit, the quote and the guarantee

Nothing is charged for the first visit, and you are under no obligation. We measure the roof and the room, check the structure, trace a cable route and note the finish you want. Afterwards a written quote arrives, itemised line by line, with the opening options shown, for example mains against solar and a rain sensor with or without a wind sensor.

One team carries out the work. Before we leave each day the opening is closed against rain, and dust sheets cover your floors. The completed work carries a 10-year workmanship guarantee, set out on our guarantee page, and the fitting follows current Building Regulations.

Homes in Bath, Keynsham and across Bristol get the same visit, because we come to you. If you would like to compare with other ways of opening a roof, the pages on VELUX windows and sun tunnels show the alternatives, and the one on roof lanterns covers raised glass for extensions.