When the thermometer passes thirty degrees, the home suddenly stops being a shelter and turns into an oven. But before you run the air conditioner all day and wait for a bill that hurts, it's worth knowing there are older, cheaper and smarter ways to keep a home cool. It requires no renovation - just a few good decisions.

The first line of defence is not to let the sun in at all. Awnings or shade cloths over windows and the terrace block the heat before it reaches the glass. Taut fabrics also have decorative value, so being practical doesn't mean being ugly.

Protection from the outside is more effective than from the inside. Roller blinds, shutters or Mallorcan louvres create a barrier before the heat gets in, while at the same time letting you regulate how much light you want and keep ventilation. If you have no external protection, solar films stuck directly onto the glass reduce heat and protect against UV rays, without sacrificing natural light.

Small gaps make a big difference. Adhesive seals on windows stop warm air from creeping in through the cracks - no construction work, and as a bonus they also improve sound insulation. Sometimes the biggest enemy is not the sun, but the invisible stream of warm air coming in where you're not looking.

Don't forget the furniture layout. Rearranging so that nothing blocks the windows lets the air flow freely from one side of the room to the other. And for natural shade and cooling, climbing plants - jasmine, ivy, bougainvillea - on a balcony or facade cool the surrounding air and look lovely while doing it.

The oldest trick is also the most free: cross-ventilation. Open opposite windows to create an airflow, especially early in the morning and in the evening when it's cooler outside. During the day, when the heat is at its peak, better to keep it closed and shaded - you let the air in when the temperature drops.

Textiles and colours work quietly but steadily. Replace heavy fabrics with linen and cotton in light tones - both physically and visually they give a feeling of freshness. Thermal curtains, specially made to repel the sun's heat, work best in light colours on large windows.

And finally, the ceiling fan - energy-efficient, it creates a constant breeze and drastically reduces reliance on the AC. Modern designs fit into almost any interior, so you no longer have to choose between comfort and looks. Put together, these small decisions make a difference of a few degrees - and in July, a few degrees is the difference between a home and an oven.