Why a week away is different from a night in
When you are at home, you are the backup for every sensor on the rooflight. When the house is empty for days, the sensor is the only thing standing between a summer storm and the kitchen floor.
Overnight, a rooflight left open has a person underneath it. If the rain sensor is slow, or a gust rattles the lid, someone hears it and presses the switch. Away for a fortnight in August, nobody hears anything. A thunderstorm rolling in off the Fens at 4pm, a squall on a Tuesday, a sensor surface covered in leaves or bird droppings: each of these has to be handled by the unit alone, again and again, for as many days as you are gone.
So the question is not simply whether the rain sensor will work. It will, in normal conditions. The question is what happens in the one case where it does not, and how long water would come in before anybody knew. The things that can stop an electric skylight closing are worth listing plainly:
- A power cut while the lid is open. Without battery backup, many actuators stop where they are.
- A sensor that has been switched off, unplugged or turned to its least sensitive setting to stop dew closing it early.
- A sensor surface fouled by leaves, pollen or droppings, so that it reads rain late.
- Debris on the frame that trips the actuator's safety stop part way through closing.
None of these is likely on any given day, but a holiday gives each of them many chances. Our page on what happens to an electric rooflight in a power cut explains what position each type of unit ends up in, and rooflight rain and wind sensors covers sensitivity settings and fouling.
Security when nobody is home
An open rooflight on an empty house is judged the way an open window would be: by how easily someone could reach it and how long they would have to work at it undisturbed.
A rooflight on the upper slope of a Victorian terrace in Romsey or De Freville is out of reach for all practical purposes. A flat rooflight on a single-storey side-return extension off Mill Road, a metre or two above a garden wall, is a different matter. With the family away, an intruder has no one to disturb them, and even a 150mm opening is something to lever at. Laminated glass and a locking closed position only help when the rooflight is actually closed.
Insurance is the other part of this. Home policies often carry conditions about securing doors and windows when the house is left unoccupied, and some have separate terms once a property has been empty for a set number of days. Whether an open rooflight counts as an unsecured window under your policy is a question for the policy wording or your insurer. Read it before you decide, because a claim for water damage or theft through an open opening is exactly where such a condition would be tested.
Heat in an empty house, and what to do about it
The reason people ask this question is usually summer heat: nobody wants to come home to a loft room or kitchen extension that has been cooking for ten days with every opening shut.
A south or west facing rooflight in July puts a lot of solar heat into a closed room, and with nobody opening anything that heat builds day after day. Leaving the rooflight open all the time is a blunt way to deal with it. During a hot afternoon the outside air can be as warm as the room, so an open lid lets in about as much heat as it lets out. What actually keeps an empty room cooler is stopping the sun before it lands on the floor.
So before a summer trip, close the blind. An external awning blind on a roof window, or a solar control blind inside a flat rooflight, keeps out far more heat than an open lid removes. If you have electric blinds on the opening rooflight, they can be set to close with the glass. Our light planning page explains why the same rooflight behaves so differently on a north slope and a south one, which is why a south-facing kitchen rooflight in a Trumpington Meadows home needs more thought in August than a north-facing loft window in Chesterton.
Using schedules, sensors and remote control while away
The best compromise for an empty house is a rooflight that stays closed and locked through the day and opens a small amount for a few hours in the cool of the night, with the rain and wind sensors left fully active.
Many electric control units can run a schedule, and a smart home hub adds more options. A sensible holiday setting might open the rooflight to its vent position after dark, when the outside air has cooled, and close it again before dawn. That clears warm, stale air from the top of the room while cutting the hours the opening is exposed. Our page on whether a rooflight can open on a timer covers the controls, and smart home control for rooflights covers linking the unit to an app.
App control brings one extra benefit: you can close the rooflight from wherever you are if the forecast turns. Check whether your system actually reports the lid's position or only sends commands, because a system that only sends commands cannot tell you whether the glass really shut.
| Setting while away | Rain risk | Security |
|---|---|---|
| Closed and locked | None | Best |
| Vent flap or small stroke | Very low | Good |
| Night schedule, sensors on | Low | Depends on reach |
| Open day and night | Relies on sensor | Weakest |
A short checklist before you go
A few minutes on the day you leave settles most of the risk, whichever setting you choose.
- Clear leaves and debris from the rain sensor and the frame, so it reads the first drops and closes without obstruction.
- Check the sensor is switched on and not set to its least sensitive level.
- Close the rooflight from the switch or app and watch the lid seat fully.
- Draw the blind on any south or west facing rooflight.
- If a neighbour has a key, show them the wall switch and how to close the unit.
If your current rooflight has no sensor, or its controls are too old to schedule, that is worth knowing before a long summer away. We install and replace electric and opening rooflights across Cambridge and about 30 miles around, and the written light plan with every quote sets out the controls, the vent position and the shading as well as where the light will land. Book a light survey or message us on WhatsApp.
Questions people also ask
Can I leave a manual rooflight open on holiday?
It is not a good idea. A manual rooflight has nothing to close it if it rains, so it stays open until you come home. Leave it shut, or use a roof window vent flap if it has one.
Will a rain sensor still work if the power goes off?
Not on its own. The sensor needs power to tell the actuator to close. Some units have a battery backup that closes the rooflight when mains power is lost, so check what yours does before relying on it.
Should I close the skylight blind when I go away?
On a south or west facing skylight in summer, yes. A closed blind stops solar heat reaching the room, which does more to keep an empty house cool than leaving the glass open.
Can I close my rooflight from my phone while abroad?
If it is linked to an app or smart home hub with internet access, usually yes. Check that the app reports the rooflight's actual position, not only the last command sent.
