Installing Attic Insulation
Should I Add Insulation into my Attic?
Most of the 130 million homes in the U.S. were not built to be energy efficient. When they were built, people didn't really care that much about how energy efficient their homes were and neither did the builders. Insulation was an afterthought. In fact, over 58 million homes have no insulation at all.
With the price of energy at all time highs, upgrading your home's insulation is starting to look like a good idea. Upgrading your attic insulation is one of the most cost effective, DIY insulation projects you can do.
It is true that heat rises. But in the summer, heat from your attic gets pulled down into your home by differences in pressure and leaky ducts connected to your central air conditioner. So no matter where you live, adding insulation to your attic will give you the biggest bang for your buck.
Your attic is also the easiest place to add insulation to an existing home. Although it won't seem like it when you're crawling around up there.
How Much Insulation Do I Need in my Attic?
Rule of thumb is at least 12" with all of the ceiling joists completely covered to reduce something known as "thermal bridging". The U.S. Dept. of Energy has a chart to help you decide how much insulation you need in your attic.
In reality, you want the best deal on insulation you can find. Which I figure is the highest level of r-value for the cheapest price.
For example, if you plan on installing fiberglass rolls or batts of insulation in your attic, the best deal is usually R30 unfaced rolls for about $0.50/sq. ft. Why buy R-19 for $0.45/sq. ft when you can almost double your r-value of a few bucks?
If you're installing blown insulation into your attic, you may be limited by the amount of insulation you can fit into your car or truck. No one has an unlimited amount of time to insulate their attic. So do your best to maximize your return for the amount of time and money you spend insulating your attic.
The Best Way to Insulate Your Attic
Adding insulation to your attic can be done two ways. You can take the easy path and blow it in or you can buy rolls of fiberglass insulation and roll it out.
Blowing hundreds of pounds of insulation through a 3" hose is obviously easier than carrying it up through a narrow attic hatch and my advice is to blow it. Blowing the insulation is a lot faster and provides more even coverage. Especially if your existing insulation doesn't reach the top of the joists.
If you decide to blow insulation into your attic, you'll need to choose between loose fill fiberglass or cellulose insulation. They both provide about the same amount of insulating power or r-value. The main difference between the two is this: fiberglass is itchy and cellulose is dusty. In my opinion, you're going to be dirty crawling around in your attic so I always use cellulose insulation. It's a much greener product made from recycled newspaper that's treated with a fireproof chemical called borate.
Do Your Prep Work First
I have a coffee mug that says, “Real men don’t need instructions.” The older I get the more I realize that’s not a good motto for me.
I wasted 2 days installing rolls of fiberglass insulation into every nook and cranny of my attic only to find out that I should have air sealed it first.
Not only did I have to pull all of the new insulation out and do it all over again, but the insulation is no longer tucked into nice, neat rolls. Instead I found myself wrestling 25’ itchy snake monsters into submission.
Learn More about Installing Attic Insulation
Prep Work for Attic Insulation
How to Install Blown Insulation into Your Attic
How to Install Fiberglass Insulation into Your Attic