How Much Ventilation Does My Attic Need?

In order for any type of attic ventilation to function properly, the air that is exhausted through the attic vent must be replaced by cooler air from outside. This is especially important when using a powered ventilator because the air turnover rate in your attic will be many times greater than that of passive ventilation methods.

The Home Ventilating Institute (www.hvi.org) recommends that powered attic ventilators provide at minimum 10 attic air volume changes per hour. To calculate the recommend amount of ventilation for your home, simply multiply the total square footage of your attic space by 0.70 as indicated in the table below, or use the Ventilation Requirements Calculator for a more accurate determination of ventilation needs. For particularly dark (black shingles) or steep roofs, HVI recommends multiplying by a factor of 0.80 to calculate your ventilation requirements. See the chart below for examples:

Attic Area (square feet)	Required Airflow (CFM)	Dark/Steep Roofs (CFM)
1,000	700	805
2,000	1,400	1,610
3,000	2,100	2,415

Additionally, HVI recommends a minimum air inlet area of 144 square inches per every 300 CFM of ventilator capacity. For Attic Breeze vents, we choose to exceed this standard and recommend a minimum outside air inlet area of more than twice that of HVI, or about 1600 square inches per a vent unit. We have found that additional air inlet area provides for better performance and reduces the risk of attic depressurization. Our outside air inlet area recommendation translates to approximately 12-13 standard size (16"x8") soffit vents per each solar attic vent.

If you don't have soffits on your home, don't worry. Installing soffits under the eaves of your home is easy and typically inexpensive (see our Installation section for more details). Also, when you have finished determining the amount of ventilation your home needs, don't forget to check out our Estimated Savings calculator to find out how much money Attic Breeze can help you save!

Ventilation Requirements Calculator

TECHNICAL

CORPORATE

News & Events

Attic Breeze offers solar attic vents, roof ventilation fans, solar attic fans, and offer solar building materials that deliver high quality performance!

Check out the new Attic Breeze AB-256 wall-mounted solar powered fans. These new fans come complete with mounting box, flush mounted louvers, and a high-efficiency remote mount 25 watt solar panel. The AB-256 will move over 1550 CFM of air and can be installed up to 40 feet away from the solar panel. These commercial fans offer both a green and affordable alternative for ventilating warehouse spaces and other large open space work areas.

New to our popular line of residential and commercial solar attic fans, Attic Breeze now offers both 20 and 25 watt solar powered gable fans. Our AB-205 and AB-255 model gable fans are the most powerful residential solar powered gable fans available anywhere! Moving over 1550 CFM of air, the AB-255 can effectively ventilate an attic space of up to 2200 sqft per a single unit. The high efficiency, industrial grade 25 watt solar panels used by Attic Breeze are powerful enough to run on cloudy days, while most other brand solar attic fans will not. Unit may be mounted up to 40 feet away from solar panel.

Incredible federal and state incentives are currently being offered for solar/photovoltaic products! Federal incentives offer everyone a 30% credit for both the purchase and installation of solar products. Many states actually offer additional incentives on top of the federal credit. To find out more details on your available incentives, click here!

Attic Breeze has a solar attic fan that’s right for any application. Our solar attic fans are designed to deliver the most attic air movement of any solar attic vent product available! Contact Attic Breeze today to learn more about attic ventilation and our solar powered attic fans.

Whether its solar attic fans, solar attic vents, or solar roof vents, Attic Breeze has your ventilation needs covered. Our solar attic fans are designed to deliver the most attic air movement of any solar attic vent product available! Contact Attic Breeze today to learn more about attic ventilation and our solar powered attic fans.

Attic Breeze manufactures the most powerful and best built solar powered ventilation products available. Our residential solar attic fans carry the only LIFETIME warranty available from any solar attic fan manufacturer! Contact Attic Breeze today to learn more about attic ventilation and our solar powered attic fans.

Attic Breeze offers more options for your solar attic fan than any other manufacturer. Whether you need solar powered gable fans, solar roof fans, or commercial solar powered fans, Attic Breeze has the right solar powered ventilation product for your application.

Attic Breeze has a solar attic fan that’s right for any application. Our solar attic fans are designed to deliver the most airflow of any solar attic vent product available! Contact Attic Breeze today to learn more about our solar powered ventilation products and how you can make a difference by going solar.

website last updated:
March 23, 2009