Solar gain and how to avoid it

11 April 2017

Will Goodenough explains how to avoid solar heat gain and apply effective measures of control.

Achieving the ideal room temperature and maintaining this at a comfortable level can be notoriously tricky. When it comes to architecture, there are many variables that can affect a room’s temperature and how it holds heat, from external weather conditions to the structural quality of the building.

However, the use of glazing, windows and rooflights can be essential in achieving the correct room temperatures, and the innovation of recent years has produced highly efficient products that have been designed with comfort, energy-saving and affordability at their core. Here we detail the basics of solar heat gain and the measures that can be taken to control it to ultimately save money and energy.

We all know the feeling: in the height of summer, or just on particularly humid days, indoor environments can quickly become uncomfortably hot, thanks to the greenhouse effect of normal, everyday glazing which magnifies the heat. This is what is referred to in the business as solar heat gain – heat from the sun accumulating to create far from ideal indoor temperatures.

Of course, the issue is only aggravated by its duality. For every sweltering day of summer, bitterly cold days are only around the corner, and on these days, heat always seems to escape quite easily. Whatever time of day, or time of year, making an indoor temperature that is comfortable requires a significant amount of attention.

If attempted incorrectly, this, of course, is precarious, costly, and detrimental to indoor air purity. In many instances, windows and doors are opened or fans and air conditioners are used to tackle excess heat, but this only works to rack up further energy costs getting the heat back out when it would be more practical to keep it from getting in at all.

On the flip side, electric heaters or central heating are used to warm the room when preferably they would be better at retaining heat in the first place.

Buildings account for 36% of Europe’s annual carbon emissions, which is staggering given that only 24% is caused by fuel-consuming transport. Every individual building is different, but it is clear that more must be done in an effort to reduce the CO2 emissions being so passively produced, day in, day out.

This is where well-designed, energy-efficient glazing comes in and provides a solution. The use of solar control glass acts to minimise solar heat gain and glare, making indoor environments much more comfortable overall. This means that when the weather is warm, indoor environments will be cool, and vice versa.

Not only is this practical, but compulsory for new constructions under the Building Regulations 2010. According to Approved Document L1A, which outlines the advisory conservation of fuel and power in new dwellings, measures such as solar control glass should be taken in all new building projects to ensure thermal and financial efficiency.

The market for solar control glass has grown by 9% in the last year alone, clearly demonstrating the direction of demand and industry focus.

Solar control glass has been found to greatly reduce heat radiation in indoor environments, with as much as 81% of radiation reflected. This is significant, and is estimated by researchers to reduce Europe’s carbon emissions by over 15 million tonnes annually.

In this way, the most unpleasant effects of solar radiation are filtered at the source, saving further expenditure on air conditioning and preventing unnecessary carbon emissions. With recent emphasis on the environmental impacts of the construction industry, this is now more prevalent than ever and should always be taken into consideration.

Financial savings are also significant, with experts estimating (dependent on individual circumstances, of course) that the average house can save anywhere between £290 and £500 a year on energy bills by implementing efficient solar heat gain control, preventing up to a tonne of annual carbon emission.

Thanks to the prominence given to energy-efficient glazing by government organisations and how prevalent it has become in regulation, the options on the market are vast and can adapt to any requirements. Heat reflecting technology is available as standard windows for general placement and use in domestic settings, and in various rooflight forms, including domes and hatches.

Make sure that you consult with a specialist regarding the arrangement that would best suit your needs when considering the use of solar control. Finding a practical solar gain control solution is beneficial not only to the everyday comfort and wellbeing of building occupants, but important to society’s collective mission towards reduced carbon emissions and efficient energy for the future.

Will Goodenough is daylight solutions director at Whitesales, a provider of roof glazing solutions. You can find Whitesales’ website here

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