A roof window lets light in from above, where it travels further into a room than light from a wall window. How much it adds depends on size, position and aspect.
In the dense streets of Ashley Down, windows on the side of a terrace look onto a neighbour, and loft rooms are often dark. A roof window changes that, because it faces the sky. It cannot be measured in neat figures, but we can explain what controls it and how to make the most of the room.
Why roof windows give more light
A window in a roof looks at open sky rather than at a wall or a fence, so daylight enters at a steeper angle and spreads further and carries deeper into the room. In practice a roof window usually brings in noticeably more light than a wall window of the same size, and the light reaches further back into the room. That is why they are popular for lofts, dormers and rooms hemmed in by neighbouring buildings.
Size and number of windows
A larger window brings in more light, but not every roof can take one. Rafter spacing, the roof structure and the room layout all limit the size. Sometimes two smaller windows side by side work better than one large one, giving more even light across the room. We advise on what the structure allows, and what trimming and doubling up of rafters would be needed.
- Rafter spacing and roof structure
- Ceiling height and headroom in the room
- Furniture and sloping walls inside
- How many windows the roof can take
Position and aspect
Where the window sits changes how it feels. A window facing south brings strong, bright light; one facing north gives softer, steadier light. A window set higher draws light deep into a room, while a lower one gives a better view. In north Bristol's terraced streets, a rear-facing roof window on a back slope often catches the most open sky.
Heat, glare and comfort
More light can also mean more heat and glare in summer. Blinds made for roof windows help control both, and ventilation from an opening window helps. The glazing, lining and insulation around the opening matter just as much, as they keep the room warm in winter. Done properly, with vapour control, it should stay comfortable all year round, without damp forming around the frame.
Planning the room
Good results come from thinking about the room as a whole: where the bed or desk will go, how people move around, and what you want to see. We talk through these before suggesting a size and position. A matching flashing kit for your roof covering is essential. Some work may need planning or Building Regulations checks, and we advise before work starts.
Frequently Asked Questions
Will a roof window make a dark loft room bright?
In most cases it makes a clear difference, since light comes straight from the sky above the roof. Brightness still depends on size, position, the number of windows and the colour of the walls and ceiling inside the room.
Is one large window better than two small ones?
Not necessarily. Two smaller windows can spread light more evenly across a room and may suit the rafter spacing better. We look at the roof and the room together before recommending an arrangement, and explain our reasoning.
Do roof windows make a room too hot?
They can in strong sun, especially facing south. Blinds designed for roof windows, opening the window for ventilation and good glazing all help keep it comfortable. Position is also a factor, which is why we discuss aspect first, before choosing a size.
Talk to our team about VELUX and roof window installation in Ashley Down
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.