March 1, 2021

Poor Design Causes Overheating

Written by Rebecca Clayton

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The Myth About Glass Extensions and Overheating

About nine out of every ten hospitals in the UK and one in five homes suffer from design flaws that can lead to excessive overheating. Thermal efficiency of a building is always a hot topic amongst designers, but during the summer months, the ability for a building to be protected from excessive heat often hits the headlines.

Glass box extension to farmhouse with sliding glass doorsResearch carried out in 2012 by the Engineering and Physical Sciences Research Council showed that temperatures in some hospital wards exceeded 30°C when the temperature outside was only 22°C.

Department of Health guidelines for new healthcare buildings, state that internal temperatures should not exceed 28 degrees for more than 50 hours per year. Considering the temperature increase seen in recent years in British summers, older and poorly designed hospital wards, with large plate-glass windows, could be facing internal temperatures even higher than this.

But overheating is not just a problem in healthcare, with just over 1/5 homes affected by overheating in the summer months. The conclusion of the recent climate change committee was that government agencies should “develop incentives for the uptake of passive cooling in existing homes, hospitals and care homes and include new measures in the next climate change national adaption plan”.

large sliding glass doors solar control glassThe introduction of solar control glazing into any large, sun-exposed windows can reduce the amount of solar radiation entering a space by up to 80%, significantly reducing the risk of overheating in a space due to solar radiation. Before glazing technologies had advanced to create solar control coatings, the poor design was the only factor resulting in overheated spaces.

When designing a glass box extension or any highly glazed space, IQ Glass studies the technical aspects such as direction, glare, and configuration to determine whether additional solar control measures are required. Working closely with both Contrasol and Grants Blinds to offer a range of internal and external solar shading solutions, the technical team is trained to advise on whether these additional precautions are necessary.

One way to reduce the risk of overheating is to ensure the space is highly ventilated. This can be achieved through the use of our opening rooflight systems, such as the M.A.R.S (Modern Automated Rooflight System) or the H.E.R.A. (High-Spec Electric Rooflight Automation)

These advanced opening systems are designed to automatically open at the click of a button, increasing the airflow through a home and helping to cool down the internal living space throughout the warmer months. The rooflight systems can be used to provide rooftop access for sky gardens or terraced roofs, as well as circulating the air and enhancing the functionality and practicality of the home

Contemporary sofa space with concealed curtains over glass wallsIQ Glass recommends solar control glass for any South-facing installations, or where oversized panes are being utilised in roof glazing. Solar gain can be used to enhance the functionality of a space if controlled in a sensible way. This could mean that when the sun is shining, heating costs are reduced in a glass box extension. Where a softer approach is preferred, recessed curtain tracks can be specified along with our luxury glazing systems, with all fixing details concealed within the building finishes for an extremely minimal design.

If you are opting for a glass extension design, it is important to use experts in the field of glazing to ensure the glass specification is carefully considered. At IQ Glass, thanks to our years of knowledge and proven expertise, our clients would never encounter an overheated space.

To speak to the team about controlling the solar gain in your glass extension project, call us on 01494 722880 or email us at