Three ways to lift the same sash
The electric vs solar rooflight question is really three questions, because the glass and frame can be identical and only the way the sash is lifted changes. A mains electric unit takes its power from the house through a transformer and a cable. A solar unit makes its own power from a small cell and keeps it in a battery. A manual unit is lifted by hand, with a winder handle, a telescopic pole or a stay arm you push up and prop.
Homeowners call all of these skylights, and the trade says opening rooflights or, on a pitched roof, roof windows. Whatever the word, the decision you are making is the same: how do you want the thing to open, who or what does the lifting, and how far do you need to reach? Get that right at the planning stage and the unit suits the room for years. Get it wrong and you have a window nobody opens.
This guide compares the three on wiring, controls, reach and the rooms they suit. The wider picture, including the opening types on both flat and pitched roofs, is on our hub for electric and opening rooflights. If you are weighing up ventilation as a whole, that is a separate subject, covered in our guide to opening rooflights for kitchen extension ventilation.
Mains electric: the one with a cable
A mains electric rooflight is the most capable of the three. It has actuators, which are small motors driving a chain, a spindle or a push rod, and they lift the sash against its own weight and against wind pressure. Many run at low voltage, with a transformer or control box somewhere handy, usually in a cupboard, the loft or the kitchen ceiling void, and a thin cable from there to the unit; others take the mains supply direct. Either way the house supply feeds it, and the connection is made by a qualified electrician.
That cable is the main thing to plan. On a new build or a rear extension that is still open to the structure, running it costs little effort, because the ceiling is not yet closed up. On an existing flat-roofed kitchen with a plastered ceiling, the route has to be thought through, and it may mean a channel in the wall or a short run across the ceiling void. We trace it at survey so the quote includes it.
The reward is control. A mains unit can be switched by a wall panel, a handheld remote, or a smart-home hub, and it can be linked to a rain sensor, which closes the unit when water is detected. The sensor has its own answer, do electric skylights close in the rain, which sets out how it behaves in full. The point for this comparison is that sensors, timers and heat or humidity triggers are happiest on a mains supply, which does not run down.
A mains electric unit suits:
- a roof lantern or flat rooflight over a kitchen extension, where you want ventilation without thinking about it
- a large or heavy sash that a person could not lift by hand
- a rooflight well out of reach, such as over a stairwell or a double-height space
- a home where a smart-home or whole-house control panel is already in place
Solar: the one with no cable
A solar opening rooflight carries a small photovoltaic cell on the frame, usually along the top. The cell charges a battery built into the unit, and the battery drives the actuators. No cable runs to it, no transformer is needed and no electrician is required for the power connection, which makes it the answer for a ceiling you do not want to open up. It is the standard solution when there is no sensible route for wiring.
A solar unit works by remote control, either a handheld remote or a wall-mounted one that does not need a cable either. Many can take a rain sensor as well. The trade-off is that the battery depends on daylight to stay charged. The cell has less to work with on a north-facing roof, or one sitting in the shadow of a taller neighbour's gable, so we talk through the orientation at survey. On a terrace with high party walls either side, a lantern at the back may get light only for part of the day.
The same point answers the question about a solar powered skylight in a Liverpool winter. The cell still charges on a grey day, but slowly, and a unit that is opened and closed many times a day uses more of the charge than one that is opened once. Where the rooflight is a room's main ventilation and is opened and closed all day, choose mains power instead.
A solar unit suits:
- a finished ceiling with no easy cable route
- a loft room or a bathroom, where the window is opened a few times a day and left
- a unit on an open, south or west facing slope with plenty of daylight
- a house where no one wants to bring in an electrician for a single roof window
The power supply is a wiring decision, so make it before the ceiling is finished.
Manual: the one with a pole or a winder
A manual rooflight is the simplest of the three, and the simplicity is a genuine virtue. On a pitched roof window, a handle at the head or foot of the sash does the job. Where the unit is out of arm's reach, a telescopic pole with a hook on the end catches a ring or a bar on the sash and pushes or pulls it. On a flat rooflight, a winder handle on a geared spindle lifts the sash a little at a time, and a gas-assisted stay arm holds it where you leave it.
There is nothing to wire, nothing to charge and nothing to go wrong with a battery, and the unit costs less than a powered one. The limit is reach and effort. A pole can be fiddly with a heavy sash, and you have to be in the room, near the pole, with a free hand. A winder asks for a few seconds of winding every time. For a window used once a day, nobody minds. For one that needs adjusting when the weather turns, you will end up leaving it open or shut for weeks.
Manual units suit a bathroom skylight above a bath, where you open it after a shower and shut it at bedtime, and they suit a loft bedroom roof window set at a sensible height. They suit a utility room too, where the opening is occasional. A rain sensor needs a powered unit, so if you want one, manual is not the route.
A manual unit suits:
- a roof window or rooflight within comfortable reach of the floor or a step
- a room where the window is opened occasionally, not through the day
- a project where the budget has to go on the glazing and the structure
- a household that prefers a mechanism with no electronics to fail
Comparing them side by side
The table sets the three against the questions we ask at survey. Read across the row that matters most to you first. For most homes, one row settles the argument.
| Question | Mains electric | Solar | Manual |
|---|---|---|---|
| Wiring | Cable and transformer | None | None |
| Controls | Wall panel, remote, hub | Remote | Pole, winder, handle |
| Reach | Any height | Any height | Within your arm or pole |
| Rain sensor | Yes | Often | No |
Two things the table cannot show. First, cost. Power adds to the price of a manual unit, and a mains job with a new cable route adds more. Our guide to what an electric opening rooflight costs sets out what drives it. The quote itself is fixed and written, and it comes only after a survey, never ahead of one. Second, the daily habit. A person who will open a window only if it takes no effort should have a powered unit, and a person who likes to feel the winder turn is happy with manual.
Choosing by room and roof
A rear kitchen extension. This is where mains electric earns its place. The room heats and fills with steam, the rooflight is high on a flat roof, and you want to open it from the worktop. In Crosby, Maghull and Wallasey you often find them on 1930s semis, with a single-storey extension built behind the original house and a ceiling that is still easy to open up. Add a rain sensor if you want it closed when you leave the house.
A loft bedroom or study. A roof window here is often within a hand's reach of the slope, so a manual handle is enough. Where it sits high above a stair, or behind a bed head, a solar unit avoids opening a finished ceiling to run a cable.
A bathroom. Moisture is the issue, and an opening unit helps a great deal. Manual works if you can reach it. Solar suits a bathroom in a loft where wiring a new run through a finished room is a nuisance.
A stairwell or landing. These are the hardest places to reach, and the best argument for a powered unit. A pole is awkward on a stair, so choose solar or mains.
A terrace with a high rear wall. The back roof of a Victorian terrace in Wavertree or Anfield often sits in the shade of its neighbours. A solar unit may charge slowly there, so we look at the light before we recommend it, and a mains unit is the fallback.
What changes on a roof that is already built, and how we decide
On an existing roof, the work is rarely the same as on a new one. A rooflight that opens needs more clear space around the frame than a fixed one, because the sash swings or lifts out of the plane of the roof, and a parapet, a chimney or a neighbouring unit can be in the way. We measure this at survey.
The same is true of weight. A powered sash with its actuators is heavier than a fixed one, and the kerb or the roof structure has to carry it. If you want to turn a fixed rooflight into an opening one, the detail is in our answer on whether a fixed rooflight can be swapped for an opening one.
Opening rooflights are building work like any other. Notifiable jobs go to Building Control through us, because the Building Regulations class any new or replacement rooflight as controlled work. The thermal limits for existing homes apply to opening units too, with roof windows at 1.4 W/m²K and rooflights at 2.2 W/m²K under Approved Document L, Table 4.2. For the planning side, see our page on planning permission for a skylight.
To choose, we start with a survey. We look at the room, the roof, the ceiling, the position of the nearest supply and the direction the roof faces. Then we tell you which of the three suits the job, and we price it as a fixed written quote. The 10-year workmanship guarantee is in writing, and the work is done with dust sheets down and the mess cleared away.
If you already have a favourite, tell us. Often the survey confirms it, and when it does not, we say why. Send a photo of the ceiling and the roof on WhatsApp, or ring us, or Get a free quote. The full range of what we fit is on the electric and opening rooflights hub.
Last checks before you choose
Can I start with a manual unit and add power later?
Sometimes. Some manual models can take a motor kit afterwards, but many cannot. If you think you may want power, say so at survey so we choose a unit that allows it.
Does a solar unit still work in a power cut?
Yes. It has its own cell and battery, so the house supply does not matter to it. A mains unit stops moving in a power cut unless it has a battery backup.
What happens if the battery in a solar unit runs flat?
The unit stays where it is until the cell has charged the battery again, and many can be opened or closed by hand in an emergency. The maker's instructions give the details for the model we fit.
Do I need an electrician of my own for a mains unit?
No. We arrange the connection with a qualified electrician as part of the job, and it appears in the fixed written quote.