Understanding Solar Shading

We can all appreciate the benefits of working in an environment where the temperature is precisely regulated. For office buildings in the summer, the optimum setting is 24oC, with a narrow range of +/- 4oC.

In many of today's office developments this temperature band can often be exceeded, especially during the hotter months, due to the solar radiation through glazing. Temperatures as high as 35-40oC have been recorded. In order to effectively regulate the internal temperature, and better protect the environment through the design of low energy buildings, the use of natural ventilation and solar shading is becoming increasingly popular.

Colt offers the architect a wide range of innovative solar shading products to overcome the problems of solar glare and solar heat gains:

Solar shading systems

Solar C - fixed Solarfin - Controllable fins - Shadoglass - Glass louvres Shadovoltaic - Photovoltaic louvres

Solar Geometry

The sun rises in the East and sets in the West. The sun travels in an arc, reaching its highest altitude in the South (for Northern hemisphere).


Orange Line - Solar Altitude for 21st December

Yellow Line - Solar Altitude for 21st September

Red Line - Solar Altitude for 21st June


An important consideration as part of the design process (especially to meet with Building Regulations Approved Document L2, 2002) is to ensure the building is shaded from the sun for as many hours as possible throughout the whole day, during the course of the entire year. However a balance must be achieved in order to ensure that the level of natural light entering the building is not unacceptably reduced.

South Facing Facades For a predominately South facing facade, effective solar shading can be achieved using a fixed horizontal solar shading system such as the Colt Solar C Shading Louvre.



During the day in both summer and spring/autumn, a fixed horizontal system projecting out from the window (length dependant) will shade the building from 8am to 5pm (office hours).

During the winter the sun is much lower and a fixed system will not work, however the heat gain and solar glare is greatly reduced in winter and therefore is not considered a major problem.

East or West Facing Facades With a predominantly East or West facing facade, a fixed system will not perform well throughout the whole day as the altitude of the sun is much lower. Sunlight and heat will pass directly under most horizontal shading systems, see illustration below.




To overcome this problem, which is now a Building Regulation requirement, a controllable shading system is required such as the Colt Solarfin System. Controllable fins, unlike fixed, can hang vertically in front of a window and still optimise solar shading and visibility thanks to specially written computer software which controls the louvres to follow the path of the sun.

This reduces the likelihood of overshading or undershading and will result in the optimum shading angle at all times.

Aesthetics and Function

In addition to Colt Solar C and Solarfin Shading fins, Colt also offer glass louvres which can be tinted in colour or have translucent laminated patterns on each of the louvres, Colt Shadoglass, and taking it one step further to provide the ultimate in renewable energy, Colt can offer its Shadovoltaic range of louvres. Photovoltaic cells are laminated onto glass louvres to store solar energy which in turn can then be used within the building for items such as lighting or heating.

Bespoke Solar Fins

Colt realise the importance of creativity and individuality when designing a building and offer many bespoke solar fins such as terracotta clay, perforated and even translucent acrylic plastics.

Track Record and Performance

Colt has over 40 years experience in designing solar shading and architectural solutions.

With operating companies strategically located world-wide, Colt has a broad product portfolio to meet your needs. In fact, the Colt Group has one of the largest and finest portfolios of both ventilation and shading products anywhere. Colt understands that a low energy building will fail on its weakest link, whatever that may be, so it specialises in integrated solutions covering all aspects including daylighting and natural ventilation. Colt is dedicated to innovation and has a comprehensive design capability, including prototyping and testing facilities. We would welcome the opportunity to develop solutions to match your requirements.