Attic Ventilation and Insulation:

Lowering Cooling Costs and Extending Roof Service Life

Attic ventilation is necessary to prevent moisture problems and heat build-up, as well as, reduce heating and cooling costs. The benefits of proper ventilation for the homeowner are a cooler attic in the summer, a dryer attic in the winter and structural protection of the home from moisture damage.

Damaged Roof Deck from Poor Ventilation

In the summer, heat builds up in the attic space, which will cool at night if the attic is properly ventilated. However, if the attic is unventilated or ventilated incorrectly, the heat will build-up over a period of days and continue to increase the temperature inside the attic. A 90-degree day with no attic ventilation can heat the roof sheath to 170 degrees or more. Heat radiating from the sheathing down to the attic floor can raise its temperature to as much as 140 degrees. Without adequate ventilation, today’s heavier insulation will absorb and hold more heat built-up during the day and make the attic less likely to cool at night.

Overheated ceiling insulation conducts the heat through the ceiling down to the residents of the home. This causes the air conditioning system to operate for longer periods of time to reduce the heat.

Generally, ventilation should be approximately 1 sq. ft. of vent area for every 150 sq. ft. of attic area. Ventilation of the attic should be "balanced" allowing for infiltration of air, usually through soffit vents under the eaves, as well as exfiltration either through ridge or gable venting. Additional venting in the form of continuous ridge vents, or powered roof vents are also an option if passive ventilation techniques are inadequate. For more information on ventilation products, calculations, and installation, visit the Lomanco® website.

Homeowners should inspect their attic ventilation system seasonally to insure that soffit vents are not blocked with dirt and insulation, and that any roof vents are not damaged/missing at the ridge. Powered roof vents should be inspected for function in both spring and fall, as motors are prone to failure due to extremes of heat/cold, as well bird nest debris. Click here for an Attic Ventilation Check List

For more information, as well as view a short video on effective attic ventilation, please visitOur Blog

Roof Damage From Lack of Ventilation

Questions? Please contact our offices to speak with a Live Home inspector! 918/812-8954 or e-mail questions to [email protected]