Home / Inspiration & advice / Which window decoration best blocks heat?

Which window decoration best blocks heat?

Aug 7, 2024

Which window decoration keeps the heat out best? We get this question more and more often at KeJe. In this article, we would like to tell you more about the options available when it comes to window decoration. Which fabrics and which window decorations are best to choose?

Keep your home cool with window decoration

With summer days becoming more extreme and houses well-insulated, keeping your home nice and cool is a challenge. Surely, the best-known solutions to keep your home cool are air conditioning or shutters. However, more and more people prefer not to use air-conditioning because of the high energy costs, among other things. Or where it is not possible or desirable to install roller shutters. They then often explore the possibilities of window decoration in combination with a fan, for example.

If you choose the right window decoration, it is certainly possible to better regulate the room temperature without high energy costs. In summer it keeps the heat out and in winter it keeps the heat in. Besides regulating, Keye window decoration even allows you to combine this with stylish/decorative looks.

Blocking sunlight and heat with window decoration

With the use of window decoration, it is possible to block direct sunlight. The sun's rays will continue to shine on your window, but they will be blocked from the inside by the window decoration. If you choose the right window decoration and act on time on hot days, this can easily save a few degrees.

The advantage of window decoration is that the products are adjustable in height, so you can decide at what height you want to fix them. Should the sun shine on a certain part of the window, it is possible to close only this part. In this way, you protect the heat but still let enough sunlight through to provide the room with natural light.

Which window decoration fabric suits my needs?

To determine which fabric and product best suits your needs, we need to look at the structure and functioning of the fabric. There are different values and components on which a fabric is tested and on which you can rate it. Below, we will explain what fabrics are tested for, so you can decide what is most important to you:

  • Rv (Light Reflection): This stands for the percentage of sunlight reflected by the fabric. The higher the percentage, the better the light reflection.
  • Av (Light absorption): This represents the percentage of sunlight absorbed by the fabric. The higher the percentage, the more light is absorbed.
  • Tv (Light transmission): This represents the percentage of sunlight that passes through the fabric. The higher the percentage, the more visible light enters the room.
  • Rs (Solar reflectance): This represents the percentage of solar energy reflected by the fabric. The higher the percentage, the better the energy is reflected.
  • Rv (Absorption by the sun): This represents the percentage of solar energy absorbed by the fabric. The higher the percentage, the more energy is absorbed.
  • Rt (Solar transmission): This represents the percentage of solar energy that passes through the fabric. The higher the percentage, the more solar energy enters the room.
  • Tuv (UV transmission): This represents the percentage of UV light that passes through the fabric. The higher the percentage, the more UV enters the room.
  • Gtot value: This represents the total transmission value of solar energy (from 0 to 1) through a combination of window and blinds. The lower the value, the less solar energy passes through the window and blinds.

Fc value important when choosing heat-resistant window decoration

The Fc value indicates how effective a particular type of fabric is at blocking solar radiation and heat in the home. The Fc value indicates the impact of the shading in terms of heat reduction (compared to the situation without shading). To calculate the Fc value, the gtot value / g value of your window is used. If blocking heat is your main goal, it is important to look at this value. The lower the Fc value the more heat you can keep out of your home. Below are the categories used:

  • Fc value is between 0.20 - 0.39: the impact on stopping heat is very high
  • Fc value is between 0.40 - 0.59: the impact on stopping heat is high
  • Fc value is between 0.60 - 0.79: the impact on withholding heat is medium
  • Fc value is between 0.80 - 0.89: the impact on withholding heat is low
  • Fc value is higher than 0.90: the impact on stopping heat is almost non-existent

Research among hundreds of "shading fabrics" showed that overall the Fc value of indoor shading is between 0.5-0.9.

Which window decoration repels heat best?

Looking at our products and the fabrics available, there are more than enough fabrics that score well on the Fc value. We grab an example below of a blackout fabric that can be used in many of our window coverings. It is a blackout fabric (shown by Tv 0%, this means 0% sunlight passes through the fabric), but also has a decorative value. This fabric is perfect for keeping out heat and can be used in both bedrooms and living rooms.

If keeping out heat is not your main goal, you can look at other values, such as Tv (Light Transmission). This represents the percentage of sunlight that passes through the fabric.

Which window decoration works best against heat?

So window decoration is an excellent way to use it as indoor sun protection. The big advantage is that it can be used not only on straight windows, but also on a skylight. Another big advantage is that window decoration also has a decorative value. So in addition to keeping the room cool, it also remains a stylish room. Another advantage is that there are no extra energy costs for running an air conditioner, for example.

Keep your bedroom or living room cool with window decoration

If you want to keep your bedroom or living room cool with window decoration, the best choice at KeJe is:

KeJe Day 'n Night combines decorative with heat protection

A choice often made and which we would like to explain further is the KeJe Day 'n Night. This is an in-house developed window decoration product, which features two fabrics. A blackout and translucent fabric is then often chosen. The Day 'n Night is fitted with an aluminium frame, which is mounted using magnetic and steel tape. This eliminates the need for drilling or screwing.

By choosing two fabrics, you can lower the blackout fabric in warm weather when the sun shines on your windows. When the sun is not shining on your window, you can opt for the translucent fabric, giving your room plenty of natural light. A window decoration ideal for both bedroom and living room.

Best advice to keep heat out of your home

The best advice from KeJe is to look at using window screens and a screen door in addition to window decoration . Even on warm days, it is often the case that the temperature drops between 21:00 and 06:00. If the outside temperature drops below the inside temperature, we recommend opening doors and windows against each other and turning on fans if necessary. Of course, it is then important to keep insects out. Therefore, always make sure a mosquito net is installed in front of every window and door. This way, you enjoy and use the cool air, but no insects get in.

When the temperature rises, we recommend closing the window blinds. If the sun is not yet shining on the windows, you can choose to keep one part open and fix the window decoration in the middle. Should the sun shine on the windows, we recommend closing the window decoration more and keeping doors and windows closed. If the window decoration is tight on the window, it is wise to keep a small gap open. This so the windows don't get too hot. This way, you keep the house relatively cool without the use of appliances that cost a lot of energy.

Customised advice from KeJe?

Are you curious about which window decoration as indoor sun protection best suits your living needs? Contact a KeJe dealer near you. Our window decoration is available in different colours and fabrics, so there is always an option that suits your interior.

Find a dealer