It is starting to get cooler outside, so now is the perfect time to talk about making your attic cooler all year long. How would you like to lower your attic temperature by 20 degrees in the summertime? This could be 30 degrees in the southern U. S.
Whether you’re building a new home or have an existing home, I’m going to tell you the benefits of an attic radiant barrier.
Let me ask you three questions.
1. In the summer, what is the hottest part of your house?
2. Where is your ductwork located? Attic or crawlspace?
3. Why would you put it in the attic?? (For 90% of you it’s in the attic, right?)
When consulting on new home construction we advise people not to put the ductwork in the attic. You can lower your cooling loads by as much as 20% just by getting the ductwork out of the attic. Now I know that isn’t always possible so we recommend placing the ductwork directly on the ceiling joists and covering it with cellulose insulation. This along with an attic radiant barrier makes for a pretty efficient heating and cooling system.
For existing home construction we advise using an attic radiant barrier that either staples to the bottom of rafters or covers your attic insulation like a blanket.
Using attic radiant barriers is not a new concept. It has been around since 1960. In 1999 Doug Rye decided to use TechShield radiant barrier roof decking on a model home. The builder has his doubts but Doug insisted on using TechShield. After it was installed, the builder was sold on it. It was summertime and he found that it was much cooler working inside the unfinished house once the radiant barrier was installed than it was outside.
Since then we have heard story after story of how radiant barrier lowers the temperature of a house during construction. We’ve heard stories from framers where they would rather eat lunch inside the house because it’s cooler than outside. Even the framers working next door eat lunch with them because it’s cooler.
The radiant barrier roof decking product is made using a process that laminates a thin, yet durable, sheet of aluminum foil to the surface of OSB board. When the sun strikes a roof, the radiant energy from the sun heats the roof and that heat radiates into the attic.
50%-75% - Radiant Heat Loss
Radiant barrier prevents up to 97 percent of that radiant heat in the roof from radiating in to the attic. As a result, it can lower the attic temperature by 30 degrees. And in the southern U. S. where temperatures easily reach 95 degrees and above, that’s a huge difference!
For years, we’ve been telling homeowners not to put the ductwork in the attic and that’s still good advice. But if your ductwork is in the attic, I recommend installing an attic radiant barrier which is available at most home centers.
By reducing temperatures in the attic, you are taking a lot of heat off the ductwork, which means your air conditioner won’t have to work as hard and you’ll save money on your electric bill. And, of course, you also need plenty of cellulose insulation in the attic to keep the heat from radiating into the living areas of the home. I’ll cover cellulose insulation in a future issue.
The most common concern people have regarding attic radiant barrier has to do with the temperature of the shingles of the roof. They want to know if it will damage the roof shingles by allowing them to get too hot. Well, the answer is no.
Attic radiant barrier won't melt the shingles. A study in Florida measured the temperatures of roof shingles above radiant barriers and found that the peak temperatures are only 2 to 5 degrees higher than the temperature of shingles on roofs without radiant barriers.
For existing home construction a thin, light weight radiant barrier can be installed. This radiant barrier is either stapled to the underside of the rafters or is laid over the ceiling insulation. This radiant barrier is clean, easy to handle, and requires no special tools or clothing.
A radiant barrier is available at most home improvement centers for around 60 cents per square foot.
Until next month, be safe and God Bless!
Phillip Rye www.philliprye.com
Doug Rye is a nationally recognized energy consultant and licensed architect. Doug also host the “Home Remedies" radio talk show that is broadcast in 15 states.
Phillip Rye is a licensed engineer and has spent the past 15 years studying energy efficiency and energy conservation.
Discover how you can have lower utility bills guaranteed! Visit http://www.dougrye.com