Does your home become unbearable in hot weather? Increasingly a hot home is an overheating office too.
During the pandemic, up to 30% of people in the UK were working from home compared with 5% in 2019.
But it's hard to work if you live somewhere that becomes an oven in hot weather.
A recent government report into climate risks warned that unless homes can be kept cool in summer and warm in winter, health and productivity will suffer.
The trick, in summer, is to bring the cool night air inside and keep it cold for as long as possible. Some mechanical ventilation systems can help - by using stale but cold night-time air leaving the property to cool the warm fresh air coming in.
Controlling the flow of hot and cold air in underfloor spaces is the aim of UK start-up AirEx.
The firm has made smart air-bricks; the ones you may see with holes in on the side of buildings.
Connected to the home's wi-fi, they use sensors and "smart algorithms" to respond to temperature, humidity and air quality.
In winter they help keep homes warm. In summer, AirEx hopes, the wi-fi-connected bricks can help keep homes cool.