Substack diary no.164: Tuesday, 26th. May 2026

The heatwave continues, with temperatures up to about 27-28 degrees celsius in south Devon today. At the moment I have temperature parity at home: it is 22 degrees outside and 22 degrees in the sitting room. Relative humidity is high – about 67 per cent outdoors and 60 per cent indoors.

My personal comfort zone is about 18 to 22 degrees, so today is rather too hot and humid. I am doing my best to keep indoor temperatures down; windows open on the shaded side of the house, blinds fully or partially closed depending on the availability of shade – and so on. However, my home is largely uninsulated so internal temperatures are higher than they should be; people often seem to forget that heat loss works both ways, and insulation helps to keep buildings cooler on hot days as well as warmer on cold days.

I would dearly love to live in a zero-energy home, and have dreamed of this for 30 years since I learned a great deal about sustainable housing. It will never happen, but I can dream can’t I? Such a home, with features like passive-stack ventilation, ambient heating, solar shading and so on would, upon entering it, feel wonderfully light, airy and healthy. I know because I have visited many back in my energy days.

I also learned in those days that to get the most out of living in such a home a little awareness and common sense is required, at least to begin with – it soon becomes second nature. We have become so familiar with mechanical devices – dials, switches, timers and so on – that their absence may at first seem disconcerting. Having said that, how many people actually know how to balance a gas central heating system using boiler thermostat, room thermostat and thermostatic radiator valves? Perhaps their absence would not be missed after all!