Attic fans are best known for their effectiveness in helping cool a house down during  summer months. Heat and humidity will build up in attics that are poorly ventilated, placing a blanket of warm air over a house that can counteract the efforts of air conditioning and other cooling systems. However, few homeowners realize the value of an attic fan in the cooler winter months. This value goes beyond simply controlling the interior temperature in the house.  Here are some wintertime benefits of attic fans.


Moisture and Humidity Control

attic ventilation

Attic humidity and moisture can cause ice buildup in an attic resulting in mold.

Homeowners in cold climates seal their houses tightly during the winter months to prevent warm air from escaping and cool air from seeping into the house through cracks and windows. During the winter, heat rises throughout a house and carries moisture and humidity with it that can get trapped in an attic or upper crawlspace. That moisture is predominantly generated and released into interior living spaces from kitchens, bathroom showers, humidifiers, and laundry facilities. When humidity levels increase in attic spaces, moisture will eventually condense out of trapped air, even during cold winter months, and drip down on attic insulation and upper floor building structures. Over time, that moisture will degrade the integrity of the upper floors of a home, result in mold and mildew growth, and can rot the roof decking. An attic fan that turns on and off in response to humidity levels can keep an attic dry during winter months, which protects insulation materials and structural framing and helps those materials to retain warmth in the home’s lower floors.


Prevention of Ice Dams

preventing ice dams

Ice damming can cause costly damage to a home.

In northern climates, snow and ice will naturally accumulate on rooftops as winter progresses. Heat can enter an attic through ceilings and poor insulation. Entry points include ceiling penetrations such as ceiling light boxes, ceiling fans, recessed lighting fixtures, smoke alarms, and others.  This heat can be trapped in a poorly-ventilated attic and will radiate through roofing materials. Snow on the heated part of the roof melts and flows down until it reaches a part of the roof that is below 32 degrees (F).  The thaw-freeze cycle allows the formation of ice dams, which is fed by melting snow above, but water held by the dam backs up and remains liquid.  Ice dams block gutters and downspouts and can cause significant damage to a home’s gutters, eaves, and roofing.  Eventually, the water finds cracks in the roof covering and flows into the attic, from where it could seep through the ceiling and interior walls, causing even greater damage.

An attic fan can keep a home’s attic and roofing from becoming warm enough to allow radiated heat to create these ice melts and dams. Proper attic insulation and in other interior spaces of the house will also help minimize warm air infiltration into the attic and causing similar problems.


Selecting an Attic Fan


solar attic fan

The Solar Attic Fan uses the FREE energy of the sun to cool a home and prevent ice damming.

Homeowners who want the most year round benefit from an attic fan should select a


product that will best work with their specific home. Some fans are powered from the home’s electrical supply. These are relatively inexpensive to install; however, they require a certified electrician to ensure a safe connection.  Electric attic fans also have a recurring cost associated with the electricity needed to power them. Other fan types, including the Solatube Solar Star attic fan, draw power from the free energy of the Sun. The Solar Star is whisper quiet, and costs nothing to run since solar energy is harvested through solar cells integrated directly into the fan unit. Solar attic fans can also qualify for a solar energy tax credit, which reduces the overall cost of materials and installation.


A homeowner should select an attic fan that is sized properly for their home’s attic volume. Installing an overpowered attic fan can create negative interior air pressure that affects furnaces, water heaters, and other natural-gas powered appliances that channel combustion exhaust outside of the house. This can be a critical matter in newer houses that are more tightly sealed against the elements.   


An experienced attic fan technician is a homeowner’s best resource for selecting the right attic fan for any kind of house. Green Home Ohio is a premier supplier and installer of Solatube Solar Star attic fans and other attic exhaust systems. Our technicians can analyze and evaluate your house to recommend the ideal attic fan for optimum winter airflow and summer heat exhaust.

Please call Green Home Ohio at 614-561-6432 to schedule an in-home consultation with one of our technicians, or for answers to your questions about attic fans.