The advantages of external blinds: innovative sun protection that maximizes daylight

What are external blinds?

External blinds or outside venetian blinds, also known as sun protection with slats on the outside of a building, are an efficient and stylish solution for controlling the amount of daylight and heat entering a space. They consist of horizontal slats that can be adjusted as needed to achieve the desired level of light and privacy.

With outside venetian blinds, you can optimally utilize daylight at any time of the day while enjoying maximum protection from prying eyes. By setting the top and bottom slats separately, you have full control over the angle of light entry and the degree of privacy you desire. Not only do you create a comfortable and pleasant living or working environment, but you also add a touch of elegance and functionality to your outdoor space.

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The benefits

Personalized light control

Perhaps the most interesting benefit is the fact that you can precisely control the light entry into your home. Want to let in the gentle morning sun? Completely block the warm afternoon sun? Or how about this: let in sufficient light with the lower slats, but tilt the upper slats so you can work efficiently in your home office without annoying sun rays on your screen. You read that right: you can set the top and bottom slats separately. This also means less need for artificial light. Hello savings!

Extra privacy

The external blinds or outside venetian blinds not only allow you to determine how much light you let in but also prevent outsiders from easily looking inside. Especially when you tilt the slats, you can be sure of complete privacy in your home at any time of the day.

Low maintenance

The slats require very little maintenance. When they do need to be cleaned, it’s very simple and quick due to their high-quality aluminium design.

Energy saving

The air circulation between your window and the external blinds keeps the heat out. Even when the slats are not completely closed, they provide a cooling effect. In winter, they retain much of the precious heat inside thanks to the air cushion when the blinds are fully closed. Thus, you save on your energy bill throughout the year.


Did you know that you can automate our outside venetian blinds? Through an app on your smartphone or tablet, or thanks to your home automation system. Moreover, you can opt for wind and sun sensors to ensure that your external blinds also react to weather conditions.

Beautiful for your facade

Lastly, but certainly not least, we’d like to add that our external blinds are simply beautiful to look at. At Harol, functionality always goes hand in hand with timeless design. You can fully personalize the slats with a wide range of colour finishes and the choice of different types of slats.

The difference with internal blinds

You might be wondering: what’s the difference with internal blinds? The main difference lies in the function: it may seem as though blinds on the inside of your window keep your home cool, but in reality, this effect is limited because the sun already gets a chance to enter your home if your window is not protected from the outside. The sun (and the heat) is already inside…

External blinds or outside venetian blinds efficiently keep the sun out and prevent the heat from penetrating your home, making the cooling effect much stronger. Internal blinds, therefore, are more decorative and primarily intended to regulate light entry, while the cooling effect is much less significant.

Types of external blinds

External blind with concealed system

With a concealed system, external blinds are installed in the facade, as if they were part of it. This is done in the cavity with a guide rail or with cable guidance and a cover cap.

These outside venetian blinds are a maximum of 5 meters wide and 5.2 meters high, with a maximum area of 18 m² to ensure optimal load-bearing capacity.

Innovative features

  • Innovative spring tension system for a stable structure of the slats
  • Various mounting options
  • Easy to clean
  • Choice of 4 slat types in an impressive colour palette
  • Resistant to gusts of wind up to 6 Beaufort
  • Effective light control- Perfect privacy protection

External blind with surface-mounted box

Our surface-mounted external blinds optimally block heat and always let in the right amount of light. This type is super easy to install, just like a surface-mounted roller shutter: the angled box is simply mounted in front of the window.

The size of our outside venetian blinds with a surface-mounted box remains slightly more limited than those with a concealed system. They are a maximum of 5 meters wide and 4.4 meters high, with a maximum area of 20 m².

Innovative Features

  • Simple installation
  • Maintenance-friendly
  • Choice of 4 slat types: AF80, AR-63 ECN, ARB-80, and AR-92 ECN
  • Effective light control
  • Perfect privacy protection
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An alternative to screens, or vice versa

Why choose external blinds over other sun protection options? They are beautiful, compact, and highly efficient in regulating light entry. They also repel the sun. Sun awnings and screens create more shade outdoors on your terrace, and screens are especially effective at completely blocking the sun.

Screens and external blinds or outside venetian blinds are often presented as alternatives to each other because both are mounted in front of the window and are compact. The type of sun protection that suits you, therefore, mainly depends on your primary goal.

Interested in the benefits of screens? Discover our screens.

In summary: the exceptional benefits of external blinds

• Sustainable, passive cooling

• Regulation of the indoor climate

• Insulating air cushion reduces heat loss (winter)

• Individual light control through adjustable slats

• Privacy protection

• High durability

• Long lifespan

• Simple operation

• Ideal for home and office

What do you think, are external blinds right for you? Discover them at a Harol distributor near you. Our distributors are all experts in their field who will gladly assist you with tailored advice.

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