If your home always feels a bit too chilly in the winter or your cooling system seems to be working overtime in the summer, you’re likely losing air and money through hidden leaks. At Insulation Services of Michigan Inc (ISM), we work with homeowners across the state who are tired of inconsistent temperatures, rising utility bills, and unclear answers. One of the most effective tools we use to diagnose air leakage is blower door testing.
This guide walks you through exactly why your home might be drafty, what blower door testing involves, and how the insights it provides can help you fix the problem with confidence. We’ll show you how to transform discomfort into control with real solutions backed by measurable results.
Blower door testing doesn’t guess where your home is leaking air it proves it. With a temporary fan system installed at an exterior door, we can precisely measure how much air is moving through cracks, gaps, and penetrations you can’t even see.
Once the test begins, the difference is obvious. We create a slight vacuum inside the home and watch how fast air rushes in through problem areas. This allows us to calculate your home’s air leakage rate and more importantly, identify exactly where the issues are.
The process takes about one to two hours. We’ll install our test equipment, depressurize your home, and use infrared tools or smoke pencils to visualize airflow. You’ll be able to feel the drafts that were once invisible. It’s a powerful, eye-opening experience that many of our clients describe as a turning point.
This test gives you more than just numbers it gives you a roadmap. Once we’ve identified the problem zones, we’ll provide honest, detailed recommendations about what to do next. Whether it’s targeted air sealing or upgrading attic insulation, we’ll help you prioritize changes that deliver real impact. Our goal is to help you get the most from every dollar you spend.
Drafty homes are more than an annoyance. They’re inefficient, uncomfortable, and costly over time. Air leaks allow heated and cooled air to escape forcing your HVAC system to run longer and work harder. That means higher bills, more wear on your system, and inconsistent temperatures throughout your home.
For many Michigan homeowners, drafts also lead to winter issues like condensation, ice dams, and moisture damage. These are signs that your thermal envelope isn’t doing its job — and a blower door test can reveal the underlying causes.
One client in Flint was frustrated with a second-floor bedroom that never stayed warm. A blower door test showed major leakage around an attic access panel and recessed lights. After sealing those areas and boosting insulation, the difference was immediate and their heating bills dropped by 18%.
At ISM, we don’t just test and walk away. Once we know where the air is escaping, we use proven methods to seal those leaks — often with foam, caulk, or weatherstripping and follow up with insulation if needed. It’s a complete, logical process designed for results.
If your home feels uncomfortable or your bills seem too high, testing is often the best place to start. It’s especially helpful in these situations:
New homes or major remodels often require blower door testing to meet energy efficiency codes. ISM is fully equipped to handle both residential and commercial tests with documentation ready for code officials.
You don’t need to have a brand-new home to benefit. In fact, many of the homes we test are decades old and they often reveal some of the most dramatic air leakage patterns. We tailor our testing approach to your home’s unique age, structure, and condition.
Blower door testing is most valuable when it’s not a one-off but part of a bigger strategy to improve your home’s performance. That’s why ISM often includes blower door testing before and after insulation projects, giving you measurable proof of progress.
We’re not here to upsell. We’re here to solve. Our recommendations are based on test data, not guesswork. If we suggest air sealing, it’s because we’ve pinpointed the exact location of air loss. If we suggest new insulation, it’s because your home is losing heat faster than it should. And if your home is already efficient, we’ll tell you that too.
Even one test can make a big difference. You’ll walk away with answers and a clear plan — whether you’re ready to move forward immediately or just need time to think through your options. Either way, we’re here to help when you’re ready.
Blower door testing is a smart, data-backed way to take the guesswork out of improving your home’s comfort and energy performance. It’s the first step toward lower bills, fewer drafts, and a more comfortable space all year long.
At ISM, we guide you from that first test through every upgrade you choose to make. No pressure. Just honest answers and proven solutions that work.
Call us at (810) 267-4121 or email kam@ismichigan.com to schedule your blower door test or ask a question. We’re here to help you build a better, more efficient home one test at a time.
It measures how airtight your home is by calculating how much air enters when a fan pulls air out a direct indicator of leakage.
Not at all. The process is safe for your home and systems. Our equipment is designed for temporary installation.
Most tests take between 60 and 90 minutes, depending on home size and complexity.
Yes, but we’ll ask that you avoid opening exterior doors during the process.
Close windows, shut off fireplaces or combustion appliances, and plan to give us access to all rooms.
The test itself reveals opportunities to lower bills. When combined with sealing and insulation upgrades, it can lead to substantial savings.
No we test homes of every age. Even new builds can leak air in unexpected places.
We’ll give you a written report and walk through the findings with you in plain language.
Yes. We handle air sealing, insulation, and related improvements after testing no need to call multiple contractors.
It varies by home size and scope, but most tests fall in the $300–$500 range. We’ll provide a clear quote up front.