This app calculates gtot, the total solar energy transmittance (also called solar factor) for the combination of a glazing and a parallel interior or exterior solar protection device, such as a louvre, a venetian or a roller blind. Venetian or louvre blinds are assumed to be adjusted so that there is no direct solar penetration.

The value of gtot is between 0 (no radiation transmitted) and 1 (all radiation transmitted).

The calculation is based on the standard ISO 52022-1:2017 (simplified calculation method). This method can also be used for inclined elements.

Restrictions: the simplified calculation method can be applied only if

- the solar factor g of the glazing is between 0,15 and 0,85.

- the solar transmittance Ts and the solar reflectance Rs of the solar protection devices are within the following ranges: 0% <= Ts <= 50% and 10% <= Rs <= 80%.

The resulting g-values of the simplified method are approximate and their deviation from the exact values lies within the range between +0,10 and -0,02. The results generally tend to lie on the safe side for cooling load estimations.

The app provides technical characteristics of 5 typical glazings (A,B,C, D and E) and contains a database with the necessary photometric values of the Helioscreen fabrics collection.