Protect roof windows against heat transfer


Loft rooms have a very serious comfort problem: they heat up enormously in the summer. Even if the loft is insulated, the heat still comes into the room through the sunlight on the skylight. How to protect the skylight against this heat transfer, and what are the advantages and disadvantages of each strategy, you can read here.

Problem solar radiation

Even if the roof space is insulated, and the temperature remains relatively constant, the sun shines through the skylights and heats up the room.

Highly insulating roof windows, as they are often used today, make sense in winter, but not in summer. They prevent the better that heat from the roof space is discharged back to the outside.

Protect roof windows against heat transfer: transfer

Possibility of darkening

Installing a dark (preferably black) roller blind on the skylight and keeping it down during the day is a way of letting less heat radiation into the room.

However, this has the disadvantage that the rooms are then dark. Of the sunshine of the day you do not have, if you sit in the darkened room.

Even indoor blinds offer the same problem, but at least they are partially adjustable. At least some light can enter the room, and it does not remain completely in the dark.

Possibility of heat-resistant roller blinds

There are special roller blinds which, with their coating, are particularly good at preventing heat radiation from penetrating into the room. Not all of these heat protection blinds are in dark colors. Brighter colors still lend some light to the room, but they are also weaker.

The heat-resistant roller blinds are also available as special, heat-protection-coated pleats. Again, bright and dark colors are available, and again the dark colors are much more effective than the bright ones.

New special coating

At the Hohenstein Institutes in Bönnigheim a special coating has been developed that works on a molecular level. From a certain, fixed temperature, the molecular structure of the thin, transparent coating changes, blocking the UV radiation.

The coating can be easily applied to all textiles and is transparent.

This has advantages:

  • starting from 23° C any further heat radiation is prevented, under it heat is always accepted
  • Light enters the room unhindered, and roller blinds can also be transparent
  • textiles coated in this way provide benefits throughout the year, in the winter as anti-glare protection, in the summer as anti-glare protection and thermal protection for temperature regulation in the room

Exterior shutters on the roof window

More effective than the protection from the inside is always the protection from the outside. The outdoor shutters can also be a way to protect yourself from the heat of the sun. However, the obscuring problem also occurs here again.

Heat protector

Special film coatings on the glass surface can keep much of the heat energy away, even without darkening. The foils are simply glued on, in winter they can even improve the heat value of the window in the case of combination foils.


Video Board: Cool roofs: How to beat the heat for top floor owners: Ep3 New Vastu with Ashok B Lall