How to Keep Your House Cool Without Cranking the AC (Tricks That Actually Work)

Every summer I find myself at odds with one room in the apartment. The bedroom, to be precise. It was my parents’ before us and it is where you get the full brunt of the afternoon sun. By evening we come back to a space that has been soaking up heat all day and is not about to let go of it; even as the rest of the place cools off after the sun has set, this room will still be holding on to its warmth. In July, stepping inside at eight o’clock is like entering an entirely different climate.

We used to put the air conditioning to work to fix it, cranking it down and leaving it on longer than was sensible. The room would become liveable enough, but then there was the end of the summer bill to contend with, which never failed to put a particular look on Tasos’s face.

Lately I have been making an effort to see what really does any good. I wanted to move past the sort of advice people give out because it sounds right and find what the research says actually makes a difference. Some of it has been an eye opener, some has borne out my own suspicions, and I discovered one much vaunted trick from the internet to be of very little use. This is the real story of what works and what is just folklore.

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The Two Things That Matter Most

Let’s put aside the rest for a moment and look at what the data on passive cooling says are the two most important factors.

Take a University of Oregon study, for instance. They put a west-facing apartment through its paces in a model o