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Before buying a roof window, you should consider the house’s interior and exterior design, ergonomics and how to get the most light from your windows. Daylight is a fundamental requirement, and human beings always respond positively to daylight. It helps us to have more energy, learn faster and be less likely to develop stress-related illnesses. It is therefore a personal investment to get as much daylight into your attic space as possible.

What to consider to maximise light from your roof windows

  • The size of the roof window
  • The number of roof windows
  • The position of the roof windows
  • The shape of the internal lining



Bigger windows of course admit more daylight, but it is also worth considering having more, smaller windows as a better overall effect can be achieved (see above).

  • Using one roof window would allow daylight to light approximately 46% of this room
  • Using two roof windows with a combined total surface area of the previous window would allow daylight to light approximately 48% of this room
  • But four roof windows with the same combined total surface area distributed more evenly would allow daylight to light approximately 65% of this room!

The right lining for maximum light

You can also let more light into the room by using the right lining. If the lining is vertical below the window, and horizontal above the window, you can allow more light to enter the room.

Free Air Circulation

Correct lining for free air circulation

Correctly splayed reveals allow more light to enter the room.
Incorrectly splayed reveals trap warm air and may cause condensation. Correctly splayed reveals trap warm air to circulate freely around the room.

Rafter Fitting

Fitting roof windows to rafters

You can also admit more light into the room by using the correct lining. If the lining is vertical below the window, and horizontal above the window, you allow more light to enter the room.

External Architecture

Outlook of the house

In addition to internal light and design, you should also consider what visual impact the roof windows will have on your house from the outside. Remember to consider the roof windows’ position in relation to existing windows in the house. Then try to balance the need for internal light with the external architecture. By doing this your roof windows will look elegant from the outside and perform according to your needs on the inside.

Snow Guards

Using a snow guard above your roof window(s) is always recommended to prevent permanent damage.


Steeper Pitch: Longer Window

A roof window should always be placed at the correct height and be the right size to suit your specific needs.
Choosing the right window size relates to the roof pitch of your house. If you have a low roof pitch, you need a larger roof window height to have the same view as in a house with a steeper roof pitch. A general rule is therefore that “the lower the pitch of the roof, the higher the roof window.”
In addition to the size of the roof window, you should also consider the height at which you want to install the roof window. It is important that most occupants in the house have a clear view out of the window.
There is no one single “correct” window size or window placement. The window should always be placed for the convenience and functionality of the users, and this can vary according to the conditions.
For the same view, a shallow pitch roof requires a taller window than a roof with a steeper pitch.

Light Control

Choose an appropriate blind

Before buying a blind you have to think about why you need a blind, so you can decide which blind type best suits your needs. In the picture you can see the effect of each blind on light and warmth.


Safety during installation

Always make sure to wear suitable protective equipment during installation. You can normally complete the installation of a roof window from the inside of the house, and scaffolding is therefore not considered necessary. However, as with all construction, there is a risk that objects might be dropped from the roof (hammer, tiles, etc). We therefore recommend that you never leave any objects lying on the external face of the roof, and that any areas at risk should be sectioned off to minimise the risk.

It is recommended that you wear safety masks and goggles when cutting any internal materials in the roof or when cutting tiles. It is also advisable to use temporary support battens whilst placing the window frame.