Retrotec

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Retrotec Retrotec is the world's leading manufacturer of blower doors, duct testers, digital manometers, and air leakage testing software.

Our equipment is trusted around the world by demanding professionals to conduct residential energy audits, large building air leakage measurements, duct leakage tests, and clean agent integrity tests.

Have you ever blower door tested an existing home and suddenly the whole house smells like a fireplace?When you depressu...
10/22/2026

Have you ever blower door tested an existing home and suddenly the whole house smells like a fireplace?

When you depressurize a house, air comes in through every opening it can find, and an open firebox full of ash is one of the easiest. A few minutes of setup before the test saves you a mess and an awkward conversation with the homeowner.

Start by knowing which standard you’re testing to. RESNET 380 and most program test requirements each spell out how the house should be set up. A typical setup looks like this:

• Windows and exterior doors shut and latched

• Combustion appliances off or set to pilot, including the water heater

• Fireplaces and wood stoves checked for ash, with dampers and doors closed

• Interior doors open

• HVAC system off

• Exhaust fans, dryer and ventilation set the way your standard requires

• Attic hatch closed, unless the attic is encapsulated and part of the conditioned space, in which case refer to your test standard

• Garage door closed

• Floor drains and traps filled with water

• Occupants asked to stay put and keep doors closed

We’re almost always pressed for time in the field, but making the effort to ensure everything is setup properly before running the fan can save us a headache later on.

Just because it’s foamed doesn’t mean it’s sealed.And just because it meets an airtightness requirement, that doesn’t me...
10/20/2026

Just because it’s foamed doesn’t mean it’s sealed.

And just because it meets an airtightness requirement, that doesn’t mean it’ll be problem free.

Sam here. This is a test I helped a builder with last week, and there are a few lessons in it.

The home tested at 1 ACH50, which most would call a good result. And at over 6,000 sq ft, this is a big house. But even a tight home can have leakage concentrated in exactly the wrong spot.

That’s why I was there. The home was completely spray foamed, and this room is on the first floor below a porch. The ceiling at the exterior wall had some biological growth on it. Once we pulled down the trim and a strip of the ceiling, we ran a blower door test with thermal imaging and saw quite a bit of air leakage through the foam.

Warm, moist outdoor air was infiltrating and condensing on the cool wood trim and drywall, and that moisture is what allowed the growth to occur.

This goes back to the diagram I made a while back showing the recipe for a full understanding of airtightness in an enclosure. The blower door number alone only tells us total leakage. We have to investigate further to know how that leakage is distributed and where it is located before we can find the source of issues like this one.

With the blower door running to -25 Pa, I used my 860i from Testo North America to capture the images.

For this one, the plan is to remove the foam above the exterior wall. There is OSB blocking acting as the air barrier over the wall. As long as that looks okay, we’ll deliberately seal it with Big Stretch from Sashco Inc.. Then flash and batt. This way, the GC can handle it himself without having to call an insulation contractor back out.

All of this could have been prevented if the home was tested and fogged before drywall went up.

homeperformance

Finished the last day of our 3-day large building training at Retrotec HQ! The main event was testing our large calibrat...
10/01/2026

Finished the last day of our 3-day large building training at Retrotec HQ! The main event was testing our large calibration building with multiple fans and equipment, with our attendees leading the way! We thoroughly enjoy getting to be hands-on with all of our onsite training opportunities, and be on the lookout for our next opportunity in spring 2027.

Wrapped up day 2 of our 3-day onsite training! In-depth lessons today with testing different fan types and utilizing a r...
09/30/2026

Wrapped up day 2 of our 3-day onsite training! In-depth lessons today with testing different fan types and utilizing a residential home as our test sample! Great benchmarking to help us perform multiple point tests as well.

Day 1 of our 3-day onsite training on large building airtightness testing at our Retrotec headquarters! Such a great div...
09/29/2026

Day 1 of our 3-day onsite training on large building airtightness testing at our Retrotec headquarters! Such a great diverse mixture of attendees, representing the Midwest, Southeast, East Coast, and even Ireland! Our attendees practiced running tests with our instructors, participated in great discussions with their own stories in the field, and got to experience some building science theories with real demo units.

09/21/2026

Sam from Retrotec walks us through some demonstrations where 3 different wall assemblies are all pressurized the same, but all 3 perform differently.

In this video, Travis Jones shows us where some of that air leakage is with the air tracer fog pen.

More cool Retrotec videos coming soon to the page from real jobs, not just trade shows - including my personal home so stay tuned!

09/21/2026

Sam from Retrotec walks us through some demonstrations where 3 different wall assemblies are all pressurized the same, but all 3 perform differently.

In the next video, Travis Jones shows us where some of that air leakage is with the air tracer fog pen.

More cool Retrotec videos coming soon to the page from real jobs, not just trade shows - including my personal home so stay tuned!

Another great round of photos from an even better week at Build Show LIVE in San Antonio.Retrotec was glad to be on the ...
09/13/2026

Another great round of photos from an even better week at Build Show LIVE in San Antonio.

Retrotec was glad to be on the floor with builders, tradespeople, designers, and building-science folks who came ready to share what is working, what is changing, and where our industry can keep improving.

Launching The Building School alongside Dan Maksymiw made the event especially meaningful. The wall assembly demos gave us a chance to walk through how air leakage can show up in different assemblies and why the details matter at every stage of construction.

The conversations, questions, and connections were the best part. Thanks again to everyone who stopped by the booth, took part in a demo, or spent a few minutes talking buildings with us.

What a week at Build Show LIVE in San Antonio!The Retrotec team had a great time connecting with familiar faces, meeting...
09/13/2026

What a week at Build Show LIVE in San Antonio!

The Retrotec team had a great time connecting with familiar faces, meeting plenty of new friends, and talking building performance with people who genuinely care about getting the details right.

We were especially proud to collaborate with Dan Maksymiw for the launch of The Building School. It was exciting to see so many people stop by and engage with the hands-on learning happening throughout the event.

Our wall assembly demo sparked great conversations about the many ways buildings leak and how construction practices, materials, and expectations have evolved over the years. There is no substitute for seeing the details up close, asking questions, and learning from one another.

Thank you to everyone who visited the booth, joined a demo, shared an idea, or simply stopped to say hello. We are grateful to be part of this community and already looking forward to the next one.

09/12/2026

Retrotec and Dan Maksymiw are teaming up to bring some next level training to home builders and all types of home performance contractors!

We’re here at Build Show LIVE with a demo showing how walls from the 90s, today’s code, and Passive House respond differently under the same conditions.

Dan Maksymiw has an incredible training facility in Chicagoland where we’ll offer the first 2 day training in the fall of 2027.

Follow along to learn more!

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Ocoee, FL
34761

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