Architects take the initiative on climate change

Phil Brown
Phil Brown

By Phil Brown, technical advisory service manager at Pilkington UK.

Climate change is the existential issue of our times.

Britain has been slowly getting warmer since the industrial revolution in the 1700s, but the full implications have only really begun to hit home in the 21st century.

Last year was the UK’s warmest year on record and temperatures topped 40°C for the first time.

It’s getting sunnier too; according to the Met Office, the 10 years to 2022 was the sunniest decade ever recorded, with 9% more hours of bright sunshine than we had in the 80s.

All around the world, weather is getting more extreme, more often.

Architects and their clients are having to account for overheating in their designs and specifications, and we have seen some truly creative and innovative approaches to the issue.

Regulators too are responding by imposing new standards.

Part O, one year on

Most notably, Part O of the Building Regulations, which came into force last year, was designed to address the growing numbers of homes overheating in summer, chiefly by limiting solar radiation and maximising ventilation.

It does this primarily by putting limits on the total glazed area allowed in new homes and requirements for openable windows for ventilation.

Homes in high-risk areas must also provide additional shading, which can be achieved by using glazing with a maximum G-value of 0.40 and a minimum light transmittance of 0.70.

One year on from Part O, we surveyed architects to understand how the regulations had impacted their working practices.

It has clearly been a challenge for some in the industry to adapt, though we did find that a small majority of architects (57%) had found compliance with Part O easy.

Seven in 10 (70%) of the architects we polled said they were specifying more solar control glazing for residential projects since Part O was introduced, such as Pilkington Suncool 70/35, specifically designed to limit solar gain in buildings.

Reassuringly, only one in seven (14%) said their most common strategy was to incorporate air conditioning systems to help limit overheating.

We’d hope to see this figure fall in the future, given that Part O steers architects away from this more energy intensive option, instructing architects to exhaust all passive measures for mitigating overheating before considering mechanical cooling.

Above and beyond

But, perhaps most strikingly, we found nine in 10 architects are going above and beyond the minimum requirements laid out in Part O.

And seven in 10 think the use of measures to combat overheating in new homes will only increase over the next five years.

Architects also argue that Part O’s most stringent rules should be applied more widely.

Seven in 10 (71%) agree that limiting the strictest measures – including specifying glazing with a maximum G-value of 0.40 and a light transmittance of at least 0.70 – to areas classed as high-risk is a missed opportunity.

Currently, the high-risk classification only includes some parts of London, as well as a few central Manchester postcodes.

And nearly nine in 10 (86%) agreed that solutions for combating overheating, like solar control glazing, are increasingly important for new UK homes as the country becomes more accustomed to experiencing the extreme heat caused by climate change.

So, does this mean that architects and developers are taking climate concerns more seriously than regulators?

It certainly appears that they are responding to recent events like last summer’s record-breaking heatwave by taking responsible and pro-active measures to ensure residents’ wellbeing.

As such, we can confidently imagine a growing role for solar control glazing in UK residential building design, even where it isn’t required by regulation.