Custom built home built with proper attic ventilation

Proper attic ventilation

There’s a lot of controversy about powered attic ventilation fans: Do they work? Do they actually reduce your energy bills? Are they worth the cost?

The answer for our climate here in Charlotte is most often a resounding no.

While our homes need ventilation – the exchange of indoor and outdoor air – it has to be the proper type in the correct amounts. Ventilation is essential to reduce our exposure to indoor pollutants like formaldehyde, volatile organic compounds, and radon that can befound in homes thanks to some building and flooring materials, rocks and soils underneath our homes, certainpaint finishes, and even appliances. Ventilation also reduces humidity in our homes. That’s essential because if humidity is left unchecked, it can lead to mold growth and even create structural damage over time. And finally, without ventilation, odors from cooking, cleaning, etc. build up in our homes’ interiors. Whole-house ventilation systems that are properly designed, sized, and installed to balance the flow of air do a fantastic job of getting rid of these components that you don’t want and keeping in the things that you do – like air that you have paid to keep at the properly heated or cooled temperature.

Just adding a powered attic ventilation fan into this perfectly proportioned mix because it sounds like a good idea actually can do more harm than good. In theory, they are supposed to reduce attic temperatures by pulling in cooler outside air – thus reducing your air conditioning costs. In most cases, experts like those at the U.S. Department of Energy agree that these fans pull at least some of the air from inside your house. That’s air that you’ve already paid to cool, which is now going into your attic where it’s not cooling down your family and is having very little impact on the overall temperature of your home. In the worst case scenario, when improperly sized or installed, these fans actually can create a negative pressure situation that causes dangerous carbon monoxide gases to backdraft into your home.

If you are looking into powered attic ventilation fans, a viable method of reducing moisture inside your home, they don’t generally function that well in our climate. That’s because Charlotte has a relatively high humidity level. That means that if the fan is pulling outside air with a higher moisture content into your attic, it actually can be causing a new moisture problem or exacerbating an existing issue.

Instead of these costly and ineffective methods, consult with a qualified general contractor about other options – like properly insulating and sealing your attic – that are more effective and healthier here in the South.