Now we’re getting somewhere.
A blower door is really a pretty simple device. Cool and effective, but simple.
As Mark Dreher, the technician from Thermo-Scan Inspections explains it: he simply opens an exterior door in the home and attaches the blower door (either fabric or hard panels) to cover the opening. Built into the blower door is a fan, which looks and sounds just like your typical box or attic fan.
The object of this test is to turn off the HVAC equipment and seal all of the vents in the home. Then, turn the fan on and begin sucking the air out of the home. This depressurizes the home. I asked Mark what depressurizing the house did: He said that by creating a pressure imbalance with the outside of the home, outside air will find a way to get indoors and equalize the pressure…if it can.
In my home outside air had absolutely no problem getting in. None at all. Mark would tell me to put my hand here and there, and sure enough, there was a pretty powerful breeze shooting in.
Mark checked all around the exterior, making notes of all the areas where air was infiltrating. Then he used an infrared camera to check the attic areas and the exterior walls. What Mark discovered was that back in 1959 they didn’t really use much insulation. Most of the attic space had none, and the few insulation batts were no longer attached. Same for the exterior walls.
Mark spent about four hours conducting the inspection. Two days later, I received his report with recommendations for fixing what he had found. I can’t really say I was surprised. The house was difficult to keep warm in the winter and cool in the summer.
Here’s what I learned: when the gas company sends those fliers that say “caulk the cracks in your home’s exterior” they are absolutely right, except for one thing: there is no way I would ever have guessed where all the leaks in the walls were without a blower door test.
If anyone is serious about improving the energy efficiency of their home, my recommendation is to begin with a blower door test. In fact, I liked the blower door test so much I decided to have another one.
Posted: 1/21/2010 12:00:00 AM by
Tom Miller | with 0 comments
Filed under: efficient, energy, homes, test, blower