Sun shading systems - after what time the costs will be returned?

The payback of the purchase costs is directly determined by the energy saved, which would have been spent on cooling (we block the heat input) and heating. The cost savings can be calculated using building energy efficiency simulation programmes.

The rate of return depends on several factors:

• the size of the window in relation to the volume of the room,
• the type of glazing, - location in relation to the world directions,
• geographical coordinates,
• the type of solar protection,
• air exchange rate coefficient with the surroundings,
• the type of automatic control adopted,
• the cost of purchasing the shade.

Taking into account the above factors, the payback time for the purchase of solar protection systems is between 5 and 15 years. A study* was carried out in our climate zone, comparing the energy consumption of windows without an external solar control system, but with glazing fitted with a coating that blocks the transfer of thermal energy, with windows with an external solar control system controlled by a sun sensor (uncoated glazing). They have shown that by using glazing with a coating that effectively permanently blocks heat energy from the sun, we are depriving ourselves of the possibility of reheating the room with solar energy in autumn-winter and winter-spring. On the other hand, by using a dynamic solar shading system, we achieve significant energy savings (for cooling and heating the building). The advantage of dynamic shading over fixed shading comes from the ability to block energy and deliver it when it is needed. The use of a solar panel makes the system fully autonomous.  Solar shading offers not only cost savings, but also comfort for users and contributes to environmental protection by reducing energy consumption.  *Based on "AWNINGS AND SOLAR-PROTECTIVE GLAZING FOR EFFICIENT ENERGY USE IN COLD CLIMATES".