Thursday, February 26, 2009

Tech Focus: House Ventilation and Solar Attic Fans

With the weather still on the cold side, you're probably not thinking much about how to keep your house cooler during the summer. Although most of us don't think about ventilation until those hot and humid days, good home ventilation is important year round.

Attic ventilation is important for several reasons. In the summer it's important to move heated, stale air out of an attic space that would otherwise keep the house feeling "stuffy" and likely cause you to turn up your air conditioner. Just as important though, proper ventilation is necessary to keep down moisture levels that could lead to mold and a shortened roof life.

Older homes often use a passive ventilation system using a combination of soffit, gable, and rooftop vents. Many homeowners install thermostat-controlled fans to assist ventilation during very hot days. While these can be a good way to help cool the home, solar powered fans can be a great alternative and run automatically from sunrise to sunset. In some cases, they can provide a significant savings on installation since running a new outlet to your attic might cost more than the unit itself. If you already have a powered vent, you may be able to convert your current unit to operate on solar power and eliminate the electricity cost.

Kevin Yount, of First Day Natural Lighting, is a local installer of Solatube lighting and attic fans. When I spoke with him about the impact of a solar fan running during the winter, he pointed out that ventilation is just as important during the winter months to prevent ice damming. The critical issue is having sufficient insulation and air sealing so that you are not losing heat from the conditioned part of the house during the winter, or losing cooling in the summer. Kevin says that in his view, the ideal temperature of the attic should be roughly equal to the outside temperature.

And since we are all concerned about job growth these days, ABC News recently highlighted Sunrise Solar, an Indiana manufacturer that builds solar units and is poised for growth with implementation of the economic recovery bill along with his suppliers. (See the video clip on ABC.)

So before those hot, humid summer days come rolling along, consider whether your home has adequate ventilation and the advantages of solar fans including:
  • Low cost to install, free to operate
  • Prevents shortened roof life
  • Helps keep home more comfortable, potentially reducing air conditioning costs
  • Creates green jobs for installers and manufacturers
And to ensure any fan meets its full potential:
  • Install adequate insulation and seal air gaps to keep from losing conditioned air
  • Make sure soffit vents are open so that outside air is pulled through the attic, not indoor air
To help find a solar fan option for your home, check out some of these sites:
  1. First Day Natural Lighting
  2. Sunrise Solar
  3. Solar Direct
To learn more about home ventilation and systems visit these sites:

Energy Star DIY Guide
DOE Energy Efficiency and Renewable Energy - Ventilation Overview

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