It looks like it’s cooler outside at night these days (below 70ºF between 9pm and 7am). I’d recommend that you air out your whole house with a big draft when th

It looks like it’s cooler outside at night these days (below 70ºF between 9pm and 7am). I’d recommend that you air out your whole house with a big draft when that’s the case: fresh air, less CO2 indoors, but also a big saving on cooling. That’s what my grandmother did all summer in Provence, and she never needed AC. If you power-cool in the afternoon to use your house as a thermal battery, you might only need to do it in the morning, but it’s always very enjoyable. People have mentioned roof insulation. It’s a good idea, although if you have solar panels, you might want to cool the outside of the roof under the panels to improve their efficiency. I’ve seen technology using water evaporation; maybe that one is less popular these days. There should be a way to do it by heating the water for your shower. The most effective idea is a lot low-tech though: outside blinds. Covering your glass windows from the outside is what prevents most of the heat from getting in. Even better if you can have slated blinds that block the sun but let the air through. Anywhere traditionally warm in summer (i.e. built before AC), I’ve seen houses with wooden blinds that you can shut all day, while you keep the windows open.