I’ve been thinking about our loft conversion and heat.
Lofts can get hot and steamy especially in the summer. I’ve been thinking about provision for air-conditioning to avoid those hot sticky nights up there. But then I read this and thought again:
From the “Home Ecologist” at the Independent:

When I popped into the local B&Q recently, it was great to see that it had an exhibition on energy saving, with good deals on bulbs and insulation, and an exhibition on solar panels. But the irony of simultaneously having a special offer on home air-conditioning units piled high at the entrance seemed to have escaped it. Studies have shown that buildings with air-conditioning can have 100 per cent higher energy bills, doubling the damage that they contribute to our climate crisis. A quick look at the energy consumption of some air-con units being marketed for home use shows that they range from 1,200 to 3,500 watts per hour – for just one room. That would be like having up to three electric fires running in each room with a unit. In comparison, a desk fan uses only 60 watts.
The crucial question is not “Which air-conditioning unit should we buy?” but “How can we avoid getting one in the first place?” There are lots of simple tips that will keep your home cooler, without using gadgets that will make the planet even hotter. The simplest is to allow as much natural air flow through your home as possible. Hot air rises, so ensure that windows or skylights at the top of the house are open, allowing it to escape. If you then open the doors and windows on the ground floor, you will generate a nice breeze. If you live in a one-storey flat or apartment, similarly try to create a through-flow of air from the front to the rear by opening windows or balcony doors, which allows the air to flow nicely. Pull the curtains on windows that are exposed to direct sunshine. The thicker they are, the better. You would be amazed what a difference this can make, especially if pulled before the sun hits the room.
Turning off all unnecessary electrical equipment and lights will also help. Halogen lights add enormously to the uncomfortable summer heat in modern homes, so get rid of them. A dozen halogen bulbs will create up to 600 watts of heat, which is the equivalent of another electric fire blazing in your ceiling. Installing air-conditioning to counteract the heat generated by these stupid lights is straightforward lunacy in the current climate crisis.
As the summers get hotter, copy our Mediterranean cousins and install retractable shades or shutters over windows that get the sun if your house is overheating. Good loft insulation will help keep the sun’s heat out, as it absolutely roasts our black British roof tiles. I switched off my solar hot-water panel the other day by mistake and was shocked to see the temperature on the roof had reached 130C.
Finally, for a deep-green touch, fast-growing deciduous trees, if planted on the south-facing aspect of a block of flats or house, will in time keep temperatures down in summer, while allowing solar gain in winter when the leaves are gone. You will also have the smug knowledge that instead of burning carbon dioxide using air-conditioning, these natural shades will absorb carbon dioxide as you watch them grow. So next time perhaps the DIY stores will pair up trees, not air-conditioning units, with special offers on energy-saving bulbs and insulation.