How Does Your Attic’s Ventilation Affect Your Energy Bill?
Attic ventilation plays an important role in maintaining a comfortable environment in the home. In fact, problems like mold and mildew and hot attic temperatures in summer can all be offset by adequate attic ventilation.
In winter, for instance, attic vents help to remove moisture from the home. This ensures problems like mold and mildew are avoided.
Yet, in summer, the attic ventilation helps to keep attic temperatures down. And that can result in real energy cost savings.
Here’s why: The summer sun beats down on the roof of your home, pushing attic temperatures over 120 degrees. This super-hot air eventually radiates into the living space, resulting in warmer interior temperatures. Ultimately, you’ll have to run your air conditioning unit longer to offset this unwanted heat gain.
How Does Attic Ventilation Work?
If you’ve ever had to retrieve something from the attic in August, you know it gets hot up there – very hot. Fortunately, your home’s insulation prevents a lot of this heat from seeping into the home. Yet, on the hottest days of the year, insulation alone isn’t enough.
Proper ventilation helps to offset the stress that’s put on the insulation. Basically, attic ventilation systems facilitate air circulation in the attic. Air intake and exhaust vents generate a natural flow of air – cooler air in via the intakes, warm air out via the exhaust vents – that helps to push the super-heated air up and out of the attic.
What Types of Attic Vents Are Available?
Attic vents are necessary for creating a circulation flow of air within the attic. In terms of exhaust, there is a range of options available; the most common include:
- Power Vents: Power vents, sometimes called PAVs, resemble box vents, but they have an electric or solar-powered fan within that help to draw moisture and hot air out of the attic. The most advanced PAVs have thermostats and humidity detectors that trigger them on.
- Ridge Vents: Ridge vents sit along the length of the roof’s horizontal ridges. An advantage: Ridge vents help to prevent hot and cool spots in the attic; creating a more even cooling effect.
What Role Do Attic Fans Play in Ventilation?
In addition to vents, your attic’s ventilation system can also benefit from fans. Yet, there are a few different types, each offer different benefits. If you want to install an attic fan, the two most common types are:
- Whole Home Fans: A whole house fan can greatly reduce your cooling costs. Essentially, this type of fan is fitted in the attic, and they’re meant to be operated at night when temperatures have cooled. Most whole home fans are floor-mounted over a central hallway within the home. They require windows on the lower floors to be opened. When turned on, the fan draws cool air through the windows, up and into the attic, helping to push warm air out of the attic. Whole house fans energy requirements are just 10-15 percent of what you could expect from the A/C unit.
- Attic Ventilation Fans: Attic ventilation fans are typically mounted to an exterior wall in the attic. This type of system blows hot air out of the attic, but it can have a negative effect. If the home is not properly insulated, a ventilator fan can actually draw cool air out of the home, resulting in an increased cooling load.
Improving Attic Ventilation for Cost Savings
Ultimately, improving your attic’s ventilation can have a net positive effect on your cooling bill. But attic ventilation requires a balance. Too many attic vents can cause temperature fluctuations in cold weather months, and too little venting will not do enough to dissipate heat in the summer.
The best advice: Consult with an HVAC specialist. A specialist will help you choose the right type of attic venting system for your roof, they can help you maximize your energy savings, and will ensure that the venting systems are properly placed and installed.
Take a look at some tips on proper attic ventilation from Mr. Roof.