It’s snowing outside, the wind is howling and there you sit in your cozy, warm home smiling with self satisfaction. Why?….
Because this past fall, you had the forethought to hire Billy Bob’s Discount Siding, Insulation and Bait Shop to re-insulate your attic with insulation – a nice, thick blanket of blown-in cellulose insulation to the impressive rating of R-50!
So what if Billy and his brothers, Darryl and Darryl, were a little sloppy in their workmanship and didn’t put down an even, smooth layer. So what if they didn’t rake the insulation to a uniform thickness but left it lumpy and bumpy? Big deal, you got 67 bags of the good stuff blown in up there! You can rest assured your heating bill will take a plunge like the 2008 stock market and your utility company will start sending you checks with all of the savings you plan to reap, right? WRONG!
You will be surprised at the large difference in the overall R-rating between a uniform layer of insulation and one with a varying thickness. That sloppy job, though seemingly insignificant, can rob you of the savings you thought you’d get. Even more so, if you have an attic access scuttle hatch or a pull down ladder or stair which is not insulated to an R value rating equal to that of your attic, you will be amazed at how quickly your R-50 turns into an R24, or less!.
LUMPY, UNEVEN INSULATION INSTALLATION
UNIFORM THICKNESS INSULATION INSTALLATION…Smoooth!
Check out the findings posted by Allison A. Bailes III, Ph.D., guest blog on GreenBuildingAdvisor.com, who explains the issue of degraded R-values from poorly installed insulation in her posting: Is There A Downside To Lumpy Attic Insulation?
http://www.greenbuildingadvisor.com/blog/dept/green-building-blog/there-downside-lumpy-attic-insulation.
Allison summarizes her dissertation from grad school in simple, laymen’s terms explaining how an assumed R-50 value can be severely degraded by peaks and valleys or by non-insulated access hatches even though they comprise a small percentage of the overall square footage. Enjoy the read and then take action.
I’m going to finish my oatmeal, get out of my easy chair and take my rake up to the attic to make sure I have a uniform layer of insulation and a rigid foam enclosure for my scuttle hole. Let the savings begin!