When the dereche hit and hundreds of thousands were without electricity, it was complicated because we simultaneously had a heat wave. Temperatures were in the upper 90s and even hit 100 degrees (38 C). As most people are addicted to air conditioning, this made for quite a lot of discomfort.
We were less affected because we didn’t have air conditioning to start with. We were already using passive cooling. Besides having a white metal roof that reflects a lot of heat, we have the habit of opening and closing windows and curtains.
We check ambient temperature and when it becomes cooler at night outside than inside we open up all the windows. When the sun shines through he south windows in the morning we close them and pull the curtains to cut off any heat gain, and when the temperature outside rises to the indoor temperature we close the rest of the windows.
We use fans in the windows to help bring the cool night air into the house.
Most days we can keep the interior temperature to 74 degrees (23 C) or less. Even after numerous days of upper 90s, the day it got to 100 (38 C) it only got to 78 degrees (25.5 C) by the end of the afternoon.
The problem with those consecutive hot days is that it doesn’t get cooler outside than inside until quite late so I was having to get up in the middle of the night to open things up whereas the normal routine is to open things before going to bed, but that was a minor inconvenience.
Anybody, even those who do use air conditioning, can adopt these techniques and save a lot of energy. Closing south curtains during sunny days will cut the workload of an air conditioner and is simple enough to do.