Harnessing Air Circulation to Cool Your Home

 Sometimes it seems like the only way to beat the heat in summer is by relying on air conditioning to cool your home.  In many cases, bad layout and design contribute to this dependence on mechanical cooling.  You’re unlikely to tear down and rebuild your home any time soon in an effort to reduce your reliance on air conditioning. But if you’re already in the process of renovating your home, it’s well worth your while to take a moment or two to consider what you can do to take advantage of natural cooling and ventilation.

The use of natural ventilation to augment your cooling can reduce your energy costs by as much as 30%. The main source for natural cooling is the windows in your house. That’s why it is of vital importance to know exactly how to position your windows to maximize the cooling effect.

Knowing the direction the wind will be coming from is integral to any discussion of natural ventilation. If you don’t already know which way the wind generally blows in your area, it is possible to acquire a summarized seasonal wind rose diagram from the National Oceanographic and Atmospheric Administration.

To maximize air flow, you’ll want the wind to enter your window head-on.  A variance of up to 45 degrees either way will still contribute to your home’s air circulation, though not as much. Having the wind enter your window at less than a 45-degree angle contributes little to air circulation.

The type of window you have installed also has an effect on air circulation. Air flow is affected by the size of the aperture that is letting the air into your home. Casement windows are ideal in this regard, since they open the widest. Additionally, the sash can act as a sort of “air scoop,” redirecting the wind into your home. In contrast, any window structure that impedes the flow of air will naturally reduce the amount of air circulation. This means that sliding, awning and single- or double-hung windows actually don’t generate an efficient amount of air flow, and are therefore not as desirable as similarly-sized casement windows.

Since you want the air to move through your home and not just into it, it’s important to make sure that you also have windows inside your home to direct the air flow through it. Ideally, you should have two windows per room, with the entrance and exit windows being indirectly opposite each other. This allows the air in the room to mix, improving the distribution and cooling effect of fresh air. Also, your home’s roof and upper floors are more exposed to wind than the areas closer to ground level; these areas should not be neglected if you’re looking to maximize the effect of natural air circulation.

Author Bio: John Zatwarnytsky is vice president of Homecraft, Inc., a family-owned home improvement company based out of Wilmington, DE. Homecraft specializes in window and door replacement, and the repair and installation of roofing, siding and gutters.

Sources:

http://www.wbdg.org/resources/naturalventilation.php

http://www.townsville.qld.gov.au/resident/planning/sustainable/Documents/Sustainable%20Housing%20Guide%202.pdf

http://sustainabilityworkshop.autodesk.com/buildings/wind-ventilation

http://sustainabilityworkshop.autodesk.com/buildings/apertures-cooling

http://sustainabilityworkshop.autodesk.com/buildings/massing-orientation-cooling