Are electric roof windows worth it?

Where a motor pays for itself

The case for an electric roof window is almost always height. A window set high above a landing, a stairwell or a bath is awkward to open with a hook and pole, and awkward windows tend to stay shut. A shut window gives no ventilation, and a room that cannot vent builds up warm, damp air.

A switch on the wall changes that. You open the sash a little in the morning, close it at night, and nobody climbs on a chair or leans over a bath with a pole.

Electric operation also suits people who find reaching or twisting hard, and it makes a loft room easier to live in on a warm day. If every window in the room sits at arm height, though, the motor adds cost and a small extra part that can fail, with little gained in return.

Our answer on top-hung or centre-pivot roof windows helps with the choice of opening style before you decide whether to motorise it, because some styles are easier to operate by pole than others.

Sensors, and what they should and should not be trusted with

Many electric roof windows can be paired with a rain sensor, a small panel on the outside of the glass that reacts to moisture and sends a signal to close the sash. That feature is the real selling point for people who leave windows ajar during the day, and we go into this further in our answer on roof window rain sensors.

Treat the sensor as a safeguard rather than a guarantee. It reacts to rain that lands on the sensor, and a dry spell with high humidity, a blown spot of spray or a flat battery will not behave like a downpour. Leaving a motorised window open while you are away for days relies on it entirely, and that is not a risk worth taking with a roof.

Some controls can also be linked to a timer, a thermostat or a wall panel that runs several windows at once. More linked equipment means more to set up and more to explain to the next owner, so ask for a written note of how your system is wired and how to reset it.

Power supply and wiring

An electric window needs power at the frame. Some models are fed by a cable run from the mains, and others run on a rechargeable battery charged by a small solar panel on the outside. Which is available depends on the manufacturer and the model, so the data sheet for the window you choose is the document to read.

A mains feed means a cable run through the roof structure to the head of the window, then a connection to a supply in the house. Leave that to a qualified electrician, and you should ask your building control body whether the work needs to be notified. Cutting into the ceiling to run the cable also leaves repairs to be made.

A solar version avoids the wiring but depends on daylight reaching the panel, and the battery needs checking over the years. It is worth asking what happens to the window if the power fails: a good unit has a manual release so the sash can still be closed by hand, and that detail matters more than any feature on the remote.

Fitting one, or adding a motor later

The easiest time to choose an electric window is when the frame is going in, because the supply route can be planned with the rafters exposed. Adding a motor to an existing manual window is sometimes possible, but whether it is depends on the maker's range for that model, so we check the frame before promising anything.

Our survey for this work starts in the loft. We look at the route a cable would take, the clearances around the sash and the condition of the frame. From outside we check the flashing and the tiles or slates up to it, because a sound window in a failing surround still leaks. We photograph whatever we find and send you the pictures.

A motor adds to the price of the window itself, and the extra labour for the supply route changes the total again. That figure is built on your roof once we have seen it, which is why a number from a website tells you little.

For the wider picture on this kind of work, see our roof windows and skylights page, and our note on the cost of fitting a new roof window for the range behind a standard fit.