Buildings with 15-20% rooflight area are more energy efficient
Incorporating rooflights into a building will cut energy use and reduce CO2 emissions. The benefits of natural daylight to the well-being of school children, care home residents, hospital patients and in the work place are well documented. The De Montfort University’s Institute of Energy & Sustainable Development is a respected authority on energy use and considerable research has shown that rooflights, combined with automatic lighting control, considerably reduces a building’s energy requirement thus lowering CO2 emissions. Simplified Building Energy Model (SBEM software) used to calculate the energy efficiency of buildings, shows that carbon emissions increase when the rooflight area is reduced below 20% of the overall roof. Combine this with the fact that studies show 93% of aluminium used in construction is recycled, rooflights should be a feature of any ‘green’ project.
Building Regulations Part L
A brief outline of the regulations is given here. However, we recommend you read our more thorough report here.
New Build Dwellings & Non-Dwellings
Part L states that rooflights should have a minimum insulation performance of 2.2W/m2.k. This is easily achievable with the Lonsdale ThermGard series glazing bars and low-e, double glazed units. Please see our QuikSpecs for typical examples of glass types. Note that rooflights with inferior performance can be used, but should be no worse than 3.3W/m2.K. However, steps must be taken to ‘trade off’ and improve other areas of the building in order to comply using the whole building method
Replacement or Additional Rooflights To Dwellings & Non-Dwellings
Rooflights being replaced or new rooflights added to existing buildings are required to have a minimum insulation value of 2.2W/m2.K
Lonsdale ThermGard Patent Glazing System can achieve excellent insulation values when combined with high performance low-e glass. We are able to provide Uvalue Data Sheets specific to your project taking into account the bar lengths, spacings & glass type enabling you to more easily gain approval by Building Control. You can view an example here, please contact our Technical Department for advice.
Life expectancy pf Items featured in our systems are suggested below:
Aluminium Extrusion Aluminium Indefinite
Powder Coating Polyester Minimum 25 years (Matt)
Fixing Brackets Aluminium Indefinite
Fixing Screws Stainless Steel Minimum 60 years
PVC-U Extrusion PVC-U Minimum 25 years
EPDM Gaskets EPDM Minimum 25 years
Thermal Break Polyamide Minimum 25 years
Silicone Weather Seal Silicone Minimum 25 years
The above are reasonable life expectations for materials installed in normal and nonaggressive environments when maintained within the manufacturer’s recommendations. Materials installed in marine or polluted environments may not last as long. This statement does not constitute a guarantee and a copy of our Warranty is available on request.