Yes, internal heat sources matter significantly, but they do not change the core strategy. During the hottest part of the day, keep windows and doors closed when outdoor temperature exceeds indoor temperature. External solar radiation and hot outdoor air typically deliver far more heat than household appliances and lighting [1]. However, you should actively minimize internal heat generation during peak hours: avoid using ovens, tumble dryers, dishwashers, and washing machines in the middle of the day; shift cooking and laundry to early morning or evening when outdoor air is cooler. Use microwaves, air-fryers, or slow-cookers instead of full ovens, or prepare cold meals. Switch off unnecessary lights and replace incandescent or halogen bulbs with LEDs, which emit significantly less heat. Put computers and electronics into low-power modes and unplug chargers when not in use.

Use cooker extractor fans while cooking to remove hot, moist air directly outside, and run bathroom extractors after showers to reduce humidity. Keep refrigerators and freezers well-sealed and properly ventilated—do not block airflow around them, as this forces compressors to work harder and generate more heat.

Once outdoor temperature drops below indoor temperature—typically in the evening or at night—open windows on opposite sides of the house to create a cross-breeze and flush out accumulated heat from both solar gain and appliances. Close windows again before dawn when outside air begins warming. Electric fans help with comfort when indoor temperature is below approximately 35°C [1]; above that threshold, they may increase dehydration by blowing hot air over the body. For vulnerable populations including elderly people, infants, and those with health conditions, monitor carefully and seek cooler public spaces such as libraries or supermarkets if your home becomes dangerously hot [2].