These days few people can take advantage of ‘the great outdoors’ as often as maybe they would like to. This is typically due to commitments that result in as much 90% of their time being spent under the harsh glare of poor electric lighting. The main issue of this lifestyle is the effect on mental health and productivity. But, with summer fast approaching, there is no better time to think about the benefits of bringing good lighting to indoor spaces. So, how do we create these sufficient levels of natural light inside?
The UK currently does not have any legislation or Building Regulations to dictate healthy levels of daylighting in either commercial or residential settings. Assessing adequate levels of light, and deciding the best course of action, is a complicated task with issues such as building location, occupancy, façade orientation, and glare requiring careful consideration. Nevertheless, including good levels of daylighting in our buildings is essential for the occupants’ well-being and helps to save energy by reducing the amount of artificial lighting which, in turn, will keep energy bills low. Using less electric lighting also helps to tackle climate change through the reduction of carbon emissions.
Vertical windows will generally only allow daylight to travel as far as 6 m inside so, for large buildings such as distribution warehouses, rooflights are the only practical way to introduce natural light into the building. Products selected for the task must meet the required target emission rates (TER) as set out in Part L2A, whilst maintaining ambient indoor environmental quality. The Notional Building specification offers a basic route to compliance, and states that a U-value of 1.8 W/m2.K is required for rooflights in a toplit building with a 15% framing factor, and 1.6 W/m2.K for windows in a side lit building with a 10% framing factor.
Some polycarbonate rooflight products are now capable of achieving U-values as low as 0.8 W/m2.K, and 1.3 W/m2.K as commonplace – well within the regulatory requirement. The material also helps to limit solar gain, making it possible to maximise the benefits of natural light without affecting the overall energy efficiency of the building.
Fully integrated roofing systems are now available on the market, making it not only easier for the roofing contractor to install, but also helping to ensure that the performance meets the design. Whether installed as part of a roof refurbishment, or as a new building design, rooflights provide opportunities for both cost and energy savings, making them a great solution for letting in more light.