Rupert Kazlauciunas, Technical Product Manager, MVHR,  Zehnder Group UK

December 2020

Back in the summer of 2019, the Good Homes Alliance launched a tool and guidance to help assess the risk of overheating in new homes. In this blog, I reflect on the positive impact the tool has had in our industry since its creation 18 months ago.

The background

The ‘Overheating in New Homes tool and guidance’ was developed with specifiers and design teams in mind. The resource helps users to calculate the level of risk of overheating, based on a number of causative and mitigating factors at the very early stages of project planning.

Taking geography, population density, barriers to window opening and likelihood of solar gains into account, the tool helps project planners to calculate how much risk there is of overheating. They can then deduct scores for every available mitigating factor, such as proximity to green and blue infrastructure, access to external and internal shading and features which support effective ventilation.

A welcome step forward

After CIBSE’s TM59 brought together ‘TM52’ and ‘CIBSE Guide A’ to create a universal document to encourage measures to control overheating in 2017, there were  calls from across our industry for an initiative to support those planning and building new homes. This tool plays an important role in responding to this call. And its popularity speaks for itself.

Over the course of the past year, it’s been downloaded over 3,000 times, and awareness of its usefulness is spreading throughout the industry.

The GHA website details some testimonials from across the built environment, emphasizing its ease of use and crucially how it can be simply used by all stakeholders involved in the design process.

Engagement with industry

The initial signs over the first 18 months have been extremely positive; it’s vital that this momentum be maintained, and experiences need to be shared – best practice, guidance documents and successes that have helped mitigate the issue of overheating in homes. The GHA have developed a knowledge base and resource library to house all related materials in one place

Engagement and support from industry bodies will certainly help in this common goal too. A positive step has been taken by the Greater London Authority in their draft Energy Assessment Guidance, April 2020. This will naturally create greater awareness of the tool and with the collective might of the wider building services community should see the tool adopted as ‘standard’.

Keeping up momentum

Thanks to industry research and initiatives such as TM59, we now have the technology, skills and opportunity to apply advanced thermo-modelling techniques to every building that is planned and constructed, to design out overheating. Add the pre-planning insight that this tool offers, and we are in a stronger position than ever to combat the problem head on before it’s too late in the design process.

The pressure is now on to ensure we continue to work together: listen to each other and acknowledge the different challenges and obstacles we all face in the planning stages, to find a common ground.

For example, if access to shading or the ability to open windows is a priority for architects, but is deemed impossible by developers or local authorities, it’s those early discussions that will identify these gaps and encourage us to find solutions that not only work for all involved, but which ultimately result in the creation of safe, comfortable and healthy homes for occupants. Keeping lines of communication open is key to success!

What next?

This 21st century phenomenon has a far-reaching impact across our industry and impacts the lives of millions of people.  Finding a workable solution will require sharing experience and expertise across the whole of the built environment.

We look forward to reporting on the strides that our combined efforts help achieve as we move positively and proactively into 2021 despite the unforeseen challenges this year!

Find out more about Zehnder and to access their overheating support materials visit

This article is a blog post authored by one of our members. Click here to see the GHA member directory, find out the benefits of membership and join our alliance today.

GHA member blog: GHA overheating tool continues to provide valuable guidance for planning and building new homes

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