How to cool an attic in summer

How to Reduce the Heat in the room?

We get a lot of such a questions from our customers. And we know how to solve this problem.

First of all we must understand why during the summer attic becomes hotter than rooms that are placed below it. That's because hot air always goes up. So hot air enters the house, goes up and stays there, because it stucks on the roof's insulation. Then sun is shining directly on the roof, heating it from one side, and at the same time warm air is collecting on the other side.

Second of all - roof windows. They look really great in the roof, give possibility of excellent view on the landscape or the sky, make interior light. But, glass absorbes the heat and gives it away to the room. Those are "weak points" of the roof. There's no insulaton there - like under the tiles, glass "sticks directly to the interior". Also Roof windows absorbs more heat than vertical ones. Therefore - the more roof windows, the hotter is inside the room. And by hotter - we mean really hot. Sometimes it is hard to get asleep in such a hot room. Even if the evening is much cooler than the day, attcic won't get cooled that quick.

How to prevent from summer heat?

Well, you can't stop physics, but we can trick it somehow :-)

There is great product, that can help to reduce the temperature in the attic - awning blind for roof window. This is an excellent anti-heat solution. Awning blind supposed to be mounted outside the roof window. In that way, that it covers whole glass. Special mesh-fabric stops the sun, reflects the sunlight and doesn't allow it to get to the glass and through it. At the same time it doesn't limit the view. It gives little shade, but still you can see through it. Most common awning blind is a manual operated one - due to it's low cost and no problems with providing power supply. Very often an operation rod is included, for smooth manouvering. There are an extension rods available, if the standard one is too short, and window is to high. But here's also possibility of purchasing solar or electric awning blinds. It is a great solution for windows, that are placed high, beyond the hands' range. Operation by a remote control or programme opening and closing the blind at certain hours is possible then. They could be compatible with smart home system.

Many customers think, that regular blackout blind will handle problem of overheating. But unfortunately - no, it will not. Why? It's very simple - it is placed behind the glass, inside the room. That means, that sunlight will get to the glass easily and (perhaps in smaller amount than when there's no blind at all) through it.

Below there's a comparison between no heat-protection, blackout blind and awning blind:

Roof window with no accessories  g = 61% ( 0,61) according to EN 410

Roof window with no accessories


Roof window with blackount blind installed g = 37% (0,37) acording to EN 13363-1

Roof window with blackount blind installed

Roof window with awning blind mounted
(depending on fabric used) g = 4-14% (0,04 − 0,14) according to EN 13363-1

Roof window with awning blind mounted

As you can see, even up to 96% of sunlight can be stopped thanks to the awning blind.

Most probably you will discover a wide range of fabrics, that are being used in blinds. Some of them may have relative fabric transparency = 10%, others 1% or different values. That means that some of the fabrics are denser than others. They are less, or more transparent, and allow to see more or less through them. At the same time, if fabric has 1% relative fabric transparency, it let less sunlight to the interior. So they are more efficient, but also more expensive at the same time.

According to our experience though even 10% transparency fabrics help to cool the air in the attic. Even up to few degrees- accoridng to our customers. So it is not necessary to buy more expensive products.

  • relative fabric transparency = 10%

  • relative fabric transparency = 1%

Also - what is important you can find many products, that are compatible with your window, even if they are not being produced by the same producer. OptiLight blinds from Kronmat (a subsidiary of FAKRO) fit to FAKRO windows and vice versa. Blinds from RoofLite (the same VKR group) fit to VELUX roof window. Of course all necessary information should be given in a product's description.

How to choose awning blind?

  • First af all you must know what type of the window you have. It is very important, because each producer has his own external and internal accessories to roof windows. Awning blind from FAKRO won't fit to VELUX window etc. That's because each producer's window has different thickness of the frame, different shape of the frame, and holes, where the scrubs should be screwed, can be placed in a different places.
  • After that you must know what size of the window you have. Please note that while buying accessories to roof windows you should always choose the same size as window's size. Of course awning blind itself will be narrower than the window, but is correct, it has to cover only glass. The best way for checking that is to find a window's nameplate. It supposed to be placed on the sash. You can find serial number there, but also type and model of the window and it's size as well.

  • Then please check if the blind, that you found in the store or online shop is dedicated to your type of window. It supposed to be written in a descriprion. If you have any doubts, you can always send a picture of the nameplate to the customers service of the following store, and seller should help you to choose proper product
  • if the product is correct, please choose size corresponding to the windows' size
  • then only installation is left

How to mount awning blind

Installation is very simple, you should follow the instruction, which is added to each blind, together with simple tools. Each producer place a ready holes in the windows, where blinds' screws should be screwed. Thanks to that you don't have to drill in the window's frame, and there's no threat that you will damage the frame and unseal the window. A blind's box should be mounted outside, at the top the window, hooks to which the awning will be hooked, should be placed at the bottom of the sash.

There is wide range of awnings on our website: awning blinds to FAKRO, VELUX, RoofLite, Skylight, OptiLight, and many others: DAKSTRA, DAKEA, SOLSTRO, LUXTRA, LUMINATEC windows. Filters placed on the top and on the left side of the website will allow you to choose awning blind compatible to your window.


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