How to Use a Cool Basement to Cool Your House

The basic principle behind cooling your house with cool air from the basement can be summarized by the old adage, hot air rises, cold air drops. In the summer, what cool air there is in a home drops and settles in the basement, while hot air rises to the upper floors. The trick to getting the hot air out and the cool air up into the living space is to use the timeless practice of natural ventilation. You can also give Mother Nature’s system a boost with electric fans in strategic locations.

Things You'll Need

• Window coverings (as needed)
• Window fans or whole house fan (as needed)

Instructions

1. Keep the house cool during the day by closing and shading windows as soon as the outdoor temperature begins to rise in the morning. Block direct sunlight through basement and other windows, using heavy or insulated window coverings; this stops heat entering the house through radiation.

2. Flush the house at night with cool air as soon as the outdoor temperature drops below the indoor temperature (called night flushing). Open the windows in upper-floor rooms and in the basement, as well as all doors between the basement and upper living spaces, to facilitate airflow.

3. Use window fans or a whole house fan to improve airflow. Place window fans blowing out in the upper-floor windows, and place fans blowing in in basement windows. A whole house fan provides the same effect as window fans but can be far more effective. Install a whole house fan into the ceiling structure between the top floor of the house and the attic, following the manufacturer’s directions. The fan blows upward, pulling hot air from the living space and into the attic, where it exits through attic vents or roof vents.

Tips & Warnings

• If you cool your home with central air conditioning and don’t practice night flushing, you can have a system installed (called Power Zoning by one company) that circulates hot air from upper-floor rooms down into the basement and sends cool air up to the same rooms, improving the overall cooling effect of your AC system.

References

• House-Energy: Natural Home Ventilation
• “Your Green Home;” Alex Wilson; 2006

Resources

• Power Zoning