Roller shutters Annelies Vandyck

Keep your bedroom cool with roller shutters and screens: but be aware of the gtot value!

A good night’s sleep is essential for our health and well-being; however, warm summer nights can cause significant discomfort. Fortunately, there are some excellent solutions to keep your bedroom cool: roller shutters and screens. These sun protection systems play a crucial role in controlling the indoor temperature, thanks to their effect on the gtot value. In this article, we explain what the gtot value is, how roller shutters and screens work, and why they are an excellent choice for cooling your bedroom.

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What is the gtot value?

The gtot value, or ‘total solar factor’, is the unit of total energy permeability of glass when combined with sun protection. In other words, the gtot value indicates how much solar energy is transmitted through a window that has sun protection. The lower the gtot value, the less heat is able to penetrate. Specifically, a gtot value of 10% means that glass and sun protection together can keep 90% of the heat out of your room. According to the EN 14501 standard, the gtot value is classified as follows:

  • Class 4: gtot < 0.10 – Very good effect
  • Class 3: 0.10 ≤ gtot < 0.15 – Good effect
  • Class 2: 0.15 ≤ gtot < 0.35 – Moderate effect
  • Class 1: 0.35 ≤ gtot < 0.50 – Little effect
  • Class 0: gtot ≥ 0.50 – Very little effect
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your coolest choice

Roller shutters

Roller shutters have an exceptionally low gtot value, between 0.02 and 0.010. This means that they only allow 2% to 1% of the solar energy to penetrate, which makes them extremely effective in keeping out the heat. Roller shutters provide an overall blackout, which not only helps to lower the temperature, but also keeps your sleeping environment comfortable and dark.

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Benefits of roller shutters
  • Maximum heat protection thanks to the low gtot
  • Blackout for a better quality of sleep.
  • Additional insulation during the winter months.
  • Improved privacy and security.
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flexible and stylish sun protection

Screens

Screens have a slightly higher gtot value, ranging from 0.07 to 0.015. Although they allow the transmission of somewhat more solar power than roller shutters, screens are still extremely effective in keeping your room cool. Screens are also versatile and stylish, allowing them to easily integrate into your home’s design.

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Benefits of screens
  • Excellent heat protection combined with attractive aesthetics.
  • Clear view of the outdoors while keeping cool indoors.
  • Easy to operate and to adapt to different window types.
  • Less glare and protection against UV rays.
  • Mosquito repellent
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How does it work?

Roller shutters and screens block and reflect much of the solar energy before it reaches your windows. This significantly reduces the heat transfer to the interior. When the sun protection is lowered, it forms a barrier that keeps out the heat, causing the indoor temperature to drop.

With roller shutters, fully covering the window ensures an almost complete blackout of sunlight and heat. Screens still allow a very small percentage of light and heat to penetrate, but significantly reduce the amount of direct sunlight entering your room, thereby keeping your home naturally cool.

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Pay attention to the gtot value

The gtot value is a crucial factor in choosing sun protection, as it directly affects the energy efficiency and comfort of your home. The lower the gtot value, the greater the protection against heat, and the more effective the sun protection will be. For bedrooms, where a cool and dark atmosphere is essential for a good night’s sleep, low gtot values are of great importance.

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Conclusion

Roller shutters and screens are both excellent choices to keep your bedroom cool during warm summer nights. Roller shutters offer the best performance with the lowest gtot values, whereas screens offer a good compromise between sun protection and aesthetics. By choosing the right sun protection, you not only improve your personal comfort, but also reduce your energy costs and contribute to a more sustainable lifestyle. Solar-powered roller shutters and screens are also available, which makes them especially sustainable.

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Annelies Vandyck
Annelies Vandyck

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