Hot summer days can have a dramatic impact on your cooling costs. Attic ventilation is an often overlooked method for reducing cooling costs.

During the day, heat from the sun beats down on your roof. The heat transfers to your attic space.

The heat builds up in your attic, and without proper ventilation, can keep your home from cooling even at night when temperatures drop. This often leads to running your air conditioner most of the night to keep living spaces cool. Removing that heat can dramatically reduce how long your air conditioner would run to cool rooms.

Your attic needs ventilation to remove heat from your attic. Proper attic ventilation is a measured combination of intake and exhaust vents based on the size of your attic. If you have a finished attic, ventilation may be more challenging. For the purposes of this post, we will be discussing unfinished attic spaces.


Attic vents are divided into two general categories – intake vents and exhaust vents. Intake vents draw outside air into the attic while exhaust vents allow hot, moist, or stagnant air to flow out of the attic.



Intake vents play an important role in keeping your attic cool in summer and dry in winter! Intake vents are typically installed at the soffit or eave. These vents draw external air into the attic.

I caution homeowners to verify that all soffit and eave vents are properly installed. Too often we find external vents are blocked (holes are not cut thru to the attic space).

Don’t assume you have ventilation just because you see ventilation screens or vents at the eave. Always check!

Additionally, we find vents are blocked by insulation within the attic because baffles are not installed or are improperly sized.  Click here for more about baffles>

vent baffle diagram



Static roof vents allow air to escape from the attic. Often multiple static roof vents are needed to adequately ventilate the attic. Roof vents should be evenly spaced across the roof and installed just below the peak of the roof where heated air will rise. Static vents do not require electricity to work and thus are less expensive to operate. They are available in a variety of colors allowing you to choose what will look best with your roof.
static roof vent image


Ridge vents also called Ridge Cap Vents are installed as you might guess, at the ridge of the roof. Ridge vents are often covered by the roofing material used on the rest of the roof making them blend to the look of your home. Designed to avoid the need for roof vents, the performance here in the Midwest has been mixed due to sub-zero temps and snow levels that can interfere with ridge vent airflow.

When using a ridge vent it is necessary to have an equal or larger amount of intake ventilation from the soffit area of the roof. This allows for air to enter at the lower vents and travel up to the top of the roof as it heats and exits out of the ridge vent. An inadequate amount of soffit ventilation will act to retard the effectiveness of your ridge vent.


Powered attic vents commonly called an Attic Fans can dramatically improve the flow of air through your attic. Attic fans are covered by a dome to keep the elements from entering the opening in your roof. The fan is connected to a thermostat or a humidistat/thermostat combo that dictates when the fan should activate based on current temperature or moisture levels in the attic. One attic fan can produce the same results as multiple static roof vents.


Bathroom Exhaust Fans and Dryer Exhaust tubes should always be exhausted externally via a dampered roof cap. Never exhaust your bathroom fan or dryer into your attic. The warm moist air exhausted from both of these sources can lead to mold and damage to your roof and home structure.

dampered roof cap image


Call us for a free ventilation assessment today at 630.830.3870. We service Chicago and All Suburbs.