Tag: Blower Door

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Blower Door Testing for Contractors, Should You Own One?

This post first appeared on the Green Building Advisor Website.

I had the opportunity to interview Gary Nelson, one of the founders of The Energy Conservatory and Minneapolis Blower Door a few years ago.  An Interview with Gary Nelson-NorthernBuilt.  During the interview, he made the comment that his hope for the blower door when it first started appearing in the market was that every contractor would own one and that testing both existing and new homes would become a common practice.  That was 40 years ago.

We haven’t got there yet, but there are more and more contractors purchasing the tool and there are many online videos and webinars showing how a blower door is set up and used.  In this blog, I’ll discuss how to perform basic diagnostics on a home using a blower door.  Methods used to find air leaks, a short discussion on zonal pressure testing, and different tasks that the manometer can perform, all topics I think a contractor that owns (or wants to own) a blower door should be familiar with.

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What is a Blower Door Test? An Introduction.

This blog post first appeared on the Andersen Windows ProViews Blog

We’ve known for a few decades that improving the air tightness of a home and installing a properly designed mechanical ventilation system can greatly enhance the performance of a home.  Having the ability to verify the airtightness of the structure is key, we perform verification by using a tool called a blower door.  This introductory blog will answer the questions; what is a blower door test?  Why do we perform blower door testing?  How is the test performed?  How do we interpret the test results?  What else can a blower door be used for?  Are there codes relating to blower door testing?  Before we dive into those questions, let’s start with that first question, what is a blower door test?

A blower door test is a test to confirm the continuity and integrity of a structure’s air barrier.

Continue reading “What is a Blower Door Test? An Introduction.”

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Northern Built Pro’s Top 5 Blog Posts for 2023

Happy New Year!  2023 was a good year for the Northern Built Pro website with 45 new blog posts, many first appearing on the Green Building Advisor website, and some that ended up in a couple trade magazines, Fine HomeBuilding and Journal of Light Construction.  I wrote a few that were directly for manufacturers of building materials, including Rockwool, Andersen Windows and Doors and Sashco.  I am looking forward to partnering with a few additional manufacturers in 2024.  A teaser to one that I am currently writing an article about, TimberHP.

These are the top 5 blog posts that were written and published in 2023.

5.  The Diminishing Return of Insulation

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An Airtight Home, What Do the Blower Door Numbers Mean?

I recently had the opportunity to attend a BS and Beer meeting in Kansas City, MO where the meeting took place in a home under construction.  The home was being built by Aarow Building (Jake Bruton) of Columbia, MO (they recently opened an office in Kansas City).  The home is a single level, slab on grade with around 3,250 square feet.  At the time of the meeting, the home was just finishing the mechanical, electrical, and plumbing systems and about to move to the insulation phase.  A perfect time for a mid-build blower door test.

The purpose of a mid-build blower door test is to confirm that the home is on track to meet the air tightness metric (Jake informed me that all his new homes are contractual bound to achieve 1 ACH50 or less) and to find any missed opportunities in the air sealing of the home.  The mid-build testing can be simple, get the home to negative or positive 50 Pascals of pressure and record the CFM rate, this type of testing is called “single point”.  If you feel the CFM rate (or the calculated air changes per hour at 50 Pascals number) is too high, set the fan on “cruise control” and go find the air leak locations.  There’s no need to perform multi-point testing this early in the build, (a type of blower door testing where CFM rates are measured at progressively lower pressure points, usually starting at 60 Pascals), save that type of testing for the final blower door test. Continue reading “An Airtight Home, What Do the Blower Door Numbers Mean?”

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Energy Audit-Blower Door Testing a Barndominium

This post first appeared on the Rockwool R-Class Website

The first time I visited one of Kyle Stumpenhorse’s (RR Buildings) jobsites was in December of 2022.  I made the trip to Illinois to blower door test one of Kyle’s Barndominium projects, the project he calls “Building a Barndominium”.  The barndo we tested was post and frame construction using closed cell spray foam (CCSF) as both the insulation and air sealing for the project.  The home tested very well, 0.41 ACH50.

Kyle (Left), Dan Edelman from Rockwool (right), and me at Kyle’s first blower door tested barndominium, December 2022.

I got to know Kyle a little on that trip, I was very impressed by his attention to detail and willingness to learn.  He pushes himself to do better on every new build.  I wasn’t surprised to find out his next project he was planning on using Rockwool insulation.  He also had a goal, beat the blower door score of the project using closed cell spray foam as the air barrier.  Could it be done?

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Code-Blower Door Testing a Small Home

This post originally appeared on the Green Building Advisor website.

Code compliant blower door testing of a small home can be very frustrating for both the person performing the test and the homeowner or contractor who are required to have the test.  A few months ago, I tested a 952 square foot, newly constructed home with a volume of 7616 cubic feet, one of the smallest I’ve tested.  The house had a leakage rate of 416 cfm which resulted in a 3.28 ACH50 number.  A failed blower door test (my climate requires 3 ACH50 or less).  If we take that same CFM rate but increase the ceiling height to 9 feet, which changes the volume to 8568 cubic feet, 2.91 ACH50, a passing test.  Either way, 416 CFM of air moving through the blower door isn’t much, some kitchen exhaust hoods can move more air than that.  Seems unfair to punish smaller homes when blower door testing, especially when the blower door test is testing the surface of a structure, not it’s volume.

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Why You Need Blower Door Testing

This article first appeared in issue 304 of Fine Homebuilding Magazine.

I bought my first blower door in 2009, back when new construction was in a downturn and energy auditing and weatherization projects were on the rise.  I took a 40-hour energy auditing training course at a local college which included hands-on training on how to use a blower door.  It took many tests before I became comfortable in its operation and understood the information it was providing.  Though one of the more expensive tools I own, I’ve been able to keep it busy and add this specialized testing to my business’s income stream.

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Building Science-Natural Air Leakage

This blog first appeared on the Green Building Advisor website.

When conducting a blower door test, one of the ways we express the findings is with air changes per hour at 50 Pascals (ACH50).  As an example, a new home is blower door tested and found to be 2.75 ACH50, this means the entire volume of air inside the home is exchanging with the outside air 2.75 time per hour at the test pressure of 50 Pascals.  When discussing blower door testing with builders and homeowners, it can be hard for them to relate to the ACH50 number other than they know the home needs to be less than a certain level of air tightness to meet current code requirements.  Expressing the tightness as natural air leakage can sometimes be helpful.  How can we calculate the natural air change rate?  Well, there’s a formula:

ACH50/n-Factor = ACHnat Continue reading “Building Science-Natural Air Leakage”

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Building Diagnostics-Single Point vs Multi-point Blower Door Testing

This Article first appeared in the September/October issue of The Journal of Light Construction.

The main purpose of a blower door test is to confirm the integrity and continuity of the air control layer or air barrier.  I have a few different options on how to perform a test.  Which option I choose is dependent on the reason I am performing the test.

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Testing-Failed a Code Required Blower Door Test, Now What?

2012 was the first year the International Energy Conservation Code required residential construction to pass an air leakage rate test, better known as a blower door test.  My area of the country requires the test to be at or below 3 air changes per hour at the test pressure of 50 pascals (ACH50).  (Other areas, typically warmer climates require 5 ACH50.)  Most new construction in my market has no problem passing the test, but I have had a handful of houses fail, usually the failed tests are by a builder having their first blower door test or the project is a very small home.

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