You have made sure your home is well insulated and sealed against the elements, keeping your home cooler in the summer and warmer in the winter. Why then would you install ventilation in your attic? Because warm air rises and your attic can get hot, even during the winter months.
However, proper attic ventilation is more than just maintaining a comfortable home temperature. It is also crucial to protect your home from damage. Read on to find out everything you need to know about attic ventilation.
Why You Need Attic Ventilation
You need attic ventilation in both the summer and the winter, whether you have an attic that is unfinished or an attic that has been converted into living space. Regardless of the time of year, heat can build up in the attic.
If heat builds up in your attic in the summer, this heat and the moisture that accompanies it can reduce the life of your roof shingles. It also makes it harder to keep your home cool, increasing energy bills as you run your air conditioning to compensate.
In the winter, enough heat can build up in the attic to cause the snow on your roof to melt, only to freeze on your eaves at night when the temperature dips. This can cause damage to your roof and result in interior leaks.
If you have attic ventilation, that warm air can escape. This makes it possible to maintain a consistent and reasonable temperature in your attic, reducing the likelihood you will damage your home.
How Attic Ventilation Works
Attic ventilation takes advantage of the fact that warm air rises and cool air sinks. The goal with attic ventilation is to bring cooler air in down low and let the warm air out through the top. Cool air is typically let into the attic at the eaves, while the warm air is let out at the peak of the roof.
The golden rule here is that there is a minimum of one square foot of attic ventilation for every 300 square feet of ceiling space. Having said this, there are experts who say this should be one square foot of ventilation for every 150 feet of ceiling space. The latter may be necessary particularly if you live in a hot, humid climate.
Attic Ventilation in an Unfinished Attic
There are different types of attic ventilation for an unfinished attic. What you use depends on your home and where it’s located. At the very least, a home should have the following:
- Roof vents – These are vents that are placed on the roof. One type is known as a ridge vent. These vents are located along the entire peak of the roof, the highest point in your home and where the warm air naturally rises. The other is known as a static vent. These vents protrude from the roof and are fitted with special covers to ensure the elements do not get inside your attic.
- Soffit vents – These are vents that are located in the planks that form the underside of the part of the roof that extends beyond the sides of your home. There are rectangular soffit vents, openings that are cut out of the wood planks at regular intervals and covered with a vent, and continuous vents, where the soffit vent runs the entire length of the soffit all the way around your house.
If roof and soffit vents don’t do an adequate job of providing attic ventilation, there are a couple of other additions you can make. These include:
- Gable vents – These are vents that are located in the gables at each end of the attic to let warm air out. They are typically made so the opening can be adjusted as needed.
- Fans – If you need more than just passive attic ventilation, particularly if you live in a hot, humid climate, you may need to install fans in the attic ceiling to help vent warm air. These fans can be powered by electricity or solar energy.
Attic Ventilation in a Finished Attic
If your attic is finished, you can still use soffit vents and ridge vents to provide attic ventilation, but you won’t want to use the traditional gable vents or fans. In this situation, you will need to rely on rafter vents.
Also known as insulation baffles, these vents are installed in the rafter space to direct the cool air coming in through the soffit vents up to the peak of the roof, pushing the warm air out the ridge vents. Rafter vents are not visible inside a finished attic space, yet they help to keep the room cool.
Final Attic Ventilation Tips
It is common for attic insulation to block soffit vents. When this happens, you will need to move the insulation out of the way of the vent to allow the air to flow through it. Always wear protective clothing and a respirator when working with insulation. In addition:
- Wear protective clothing and ear and eye protection when cutting into the soffit.
- Avoid working in the attic at the hottest time of the year.
- Make sure you work in dry weather and that you use appropriate ladder safety equipment.
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