Manage windows, blinds, and cross-ventilation

Block sunlight during the day and flush hot air out at night using strategic window management and natural airflow. These passive techniques can lower indoor temperatures by 5-10°F without any energy cost.

How to Do It

1. Block daytime sun: Keep windows closed and blinds or curtains drawn on sun-facing sides (south and west in the Northern Hemisphere) during peak heat hours.
2. Ventilate at night: Once outdoor temps drop below indoor temps, open windows on opposite sides of the house to create cross-ventilation.
3. Use the stack effect: Place a box fan facing outward in an upstairs window to push hot air out while opening lower windows on the shady side to draw cool air in.
4. Add exterior shading: Awnings, shade sails, or deciduous trees block solar heat before it reaches the glass -- far more effective than interior blinds alone.

Tips

• Close windows and blinds again by mid-morning before outdoor temps climb
• Reflective or blackout curtains outperform standard drapes for heat blocking
• Even one well-placed shade tree on the west side makes a noticeable difference