Quick Answer: How Big Should My Gable Vents Be?

How do you size a gable attic fan?

Vent Fan Size Next, multiply the square feet of attic space by 0.7 to get the minimum number of cubic feet of air per minute that the fan should be rated to move.

Add an additional 20% (CFM x 1.20) if you have a steep roof, and 15% (CFM x 1.15) for a dark roof..

Can you have too much attic ventilation?

It’s possible to have too much exhaust ventilation, but you cannot have too much intake ventilation. If there is more intake ventilation than the attic’s square footage requires, it’s not problematic because any excess intake converts to “exhaust” on the leeward side of the house.

What happens if attic is not vented?

But in homes without appropriate insulation and ventilation in the attic, heat migrates. … Meanwhile, because hot air is full of moisture, all that water hanging out in your attic is causing condensation to build up. Excess heat and condensation can cause major damage to your roof and roofing materials.

How do you tell if attic is properly vented?

Here are four signs of an unventilated or under ventilated attic:Look at your eaves and roof. … Touch your ceiling on a warm, sunny day. … Thick ridges of ice on your eaves in winter are a sign of poor attic ventilation.More items…

How much does it cost to install gable vents?

They cost between $35 and $50 per vent to install. Gable vents, or wall louvers, are placed in the gable ends of the attic and can be used in combination with other vents. The higher they are, the more effective.

Are gable attic fans worth it?

Even if your roof already has ridge vents and plenty of ventilation built in, it’s a good idea to install gable fans or roof fans to help blow hot, humid air out of the attic. Attic ventilation fans also tend to be quite energy-efficient in terms of their own operation.

How do you measure for a gable vent?

How to Measure Gable VentsMeasure the length and width of your attic floor with a tape measure. … Multiply the length by the width to determine the square footage of attic space you need to ventilate. … Divide your total square footage by 300 to determine the vent area. … Purchase gable vents that match the net vent area from your calculations.

Are gable vents adequate?

Gable vents will work if thy are large enough to give adequate trough-flow of air, but ridge and soffit vents are much more efficient. … My experience with gable vents is they only work when the wind is blowing and blowing directly into a vent.

Do I need soffit vents if I have gable vents?

Intake Vents Unfortunately, blocked soffit vents are as just bad as no soffit vents, because they prevent fresh air from freely flowing into the attic. Houses with gable roofs may also have vents located on the side of the house as high as possible within the peak of the gable.

Should gable vents be closed in winter?

You should absolutely leave your roof vents open during the winter – do not cover them! During the winter, roof ventilation works to keep temperatures even. Closing your vents makes the attic space too warm and dry – dangerous conditions for mold as well as pests.

Can I have too many soffit vents?

You can’t have too much soffit venting, but it’s worth noting the minimum requirements. Usually, 4-in. by 16-in. soffit vents are rated for 26 sq.

Do gable vents interfere with ridge vents?

Gable vents will alter the air flow around the ridge vent and, especially when wind is parallel to the ridge (at right angles to the gable), can actually reverse air flow through the ridge vent, pulling rain or snow into the attic. … The most efficient option is ridge venting combined with continuous soffit vents.

What should attic fan thermostat be set at?

between 100 and 110 degrees FahrenheitMost attic fans operate with a thermostat that automatically turns the fan on and off based on a temperature the homeowner sets. Most manufacturers and contractors recommend a temperature setting between 100 and 110 degrees Fahrenheit.

Are ridge vents better than attic fans?

The majority of roofing experts agree that ridge vents are the most effective and cost-effective roof vents available. Without baffles (blinders that prevent outside air from crossing over the vent), a ridge vent may create almost no ventilation at all. … Soffit vents may leave air trapped at the top of your attic.

Does a finished attic need to be vented?

When done correctly, attic venting can reduce the potential for condensation in winter and summer. … Even when outside air is hot and humid, if the attic space is air-sealed from the interior, it is much hotter than outside air. The hotter the air, the more moisture (i.e. absolute humidity) the air space can hold.

Do gable vents leak?

Virtually all gable end vents (Figure 9) will leak when the wall they are mounted on faces into the wind- driven rain. … If installation of shutters from the outside is difficult because of the height or other considerations, but there is access through the attic, the gable vent opening can be shuttered from the inside.

Do attic fans save money?

Ventilation fans, or powered attic ventilators, are designed to cool the attic, pushing out the hot attic air and rushing in a flow of cool outside air. … The intention of the ventilation fan is to save energy and the roof. Energy would be saved by reducing the burden of the air conditioner in the home.