How to Pass a Blower Door Test – Made Easy
We find many of our new customers often worry about passing the blower door test for the Illinois Energy Conservation Code. To ease the minds of our current and future customers we decided to put together these tips along with real world results we have seen over the last 8 years since the State of Illinois started requiring air tightness testing as part of the state wide energy code.
First, let’s qualify what “passing” means in Illinois. The Illinois Energy Conservation code is based off of the IECC 2015 National Energy Code. However, Illinois adopted the code with a few amendments – one of which is related to blower door testing. The national code says homes in climate zone 5 (think north of Interstate 80 to the boarder) should be able to meet 3 air changes per hour or 3ACH while the home is depressurized to a pressure of 50 Pascals, or 3ACH50. Illinois decided this standard was to stringent for a number of reasons and loosened the standard to 5ACH50. Meaning our homes can leak 167% of the required national standard and still pass.
What this means is, in the last 8+ years of doing testing, we’ve only seen a handful of homes fail this test. Its not to say we don’t see homes fail, we just don’t see many of them.
Interesting enough, the state of Illinois has also educated our building code officials to inspect our homes at rough (before drywall), and provide guidance on how to seal up the homes to ensure they will pass energy code. This inspection is based on the IECC Energy Code checklists which have been in place since 2009. Here is a presentation very similiar to what are code officials have seen – Achieving Tight Envelopes.
Guess what, if you follow these guidlines your homes will come in around 3ACH50 or below and you will find your homes to have far fewer problems; interesting enough, the homes we see come in between 4ACH50 and 5ACH50 are the ones having problems such as:
- Hard wood floor movement (buckling, seperating, etc…)
- Moisture at and around windows
- Drywall frosting in the winter
- Attic Mold Issues
Here’s a summary of blower door test results we’ve seen in Ilinois; stay tuned, we will be adding links for each city so you can see how some of our customers have faired since they started working with us.
