Designers Have to Minimise the Risk of Overheating

17 Oct 2018

Why is overheating a problem, and why now?

We are in a warming climate (see map below). We’re also getting higher densities and new typologies such as single-aspect apartments. Because there is more focus on energy efficiency, we’re getting more airtight buildings but ventilation systems aren’t always performing as they should.

All these things together create a perfect storm of overheating, which is particularly a problem for vulnerable people and those who are inside all day.

What are the potential solutions?

While overheating is increasing, we’re also understanding more about how buildings perform in use. The perfect solution is for designers and planners to understand the causes of overheating and for these to be controlled by the Building Regulations, which are shortly being reviewed to address energy efficiency and other issues. This will take time.

Meanwhile, a draft review of the National Planning Policy Framework (NPPF) has flagged overheating as an issue for planning authorities, but until the regulations change a method for managing this is unclear. The Good Homes Alliance is producing guidance to address some of these issues at the early stages of design.

What can designers and planners do to help?

First they have to be aware of the issues causing overheating and design to minimise the risk, including night cooling where possible – this can be a challenge in urban areas with noise and security issues. Exposed thermal mass, which can absorb heat during the day, can help reduce excess heat, provided it can be dissipated at night through ventilation.

Any single-aspect flats need to be properly shaded. Designers also need to be aware of the potential for overheating caused by communal heating systems, which need to be highly insulated. It’s important to flag up all these issues at an early stage of design review.

What role can concrete play in maintaining comfortable temperatures in a warmer future climate?

A lot of research has been done on the use of exposed concrete for thermal mass. We’ve been a bit slow to explore its potential, which could also lead to some interesting hybrids – for example, the integration of thermal mass into lightweight buildings.

With the reviews of the Building Regulations and NPPF, the overheating issue is clearly on the agenda – we will now need to fine-tune our ability to manage it.

Lynne Sullivan is founder of LSA architects and chair of the Good Homes Alliance