Designing for Warmer Summers – Part 1

Rethinking design for warmer summers

With another heatwave pushing temperatures past 30°C across the UK this week, it’s a good moment to ask: are we designing homes for the climate we have, or the one we used to have?

For decades, UK homes have been designed to keep heat in. Now, increasingly, the challenge is keeping heat out and that means rethinking some fundamentals rather than just bolting on air conditioning.

Since 2022, Part O of the Building Regulations has made this a legal requirement for new homes, and it sets a clear hierarchy: reduce unwanted solar gain first, then remove excess heat through ventilation, and only turn to mechanical cooling as a last resort.

In practice, that shapes real design decisions:

Orientation and glazing ratios, so we’re not creating south-facing glass boxes that trap heat
External shading, i.e overhangs, louvres, brise soleil, or simply well-placed trees are all far more effective than internal blinds.
Cross and night-time ventilation, designed in from the outset rather than added later
Thermal mass and material choice, to even out temperature swings through the day