Passive Podlympics I | And the winner is…

Last week we ran our accredited PHI course to become a Certified Passive House Tradesperson. Builders from all over the country joined us at our office in Arvada (Denver), Colorado, for five days of intense learning and growing. We’ve now had several alumni describe the experience as “drinking water from a firehose“, based on the amount of applicable and important information that they are able to take back to their practices.

Every time we run the class, we make improvements to the curriculum and the way in which we engage the builders to implement the knowledge they are absorbing in the classroom setting. We have the fortune of receiving product donations from the best of the best in the Passive House manufacturing world, and we give the students an opportunity to ask questions in a brand-neutral environment where science reigns.

You may remember little Mitch the Mockup? Well, we’ve stepped up the game, and our Italian teacher has now come to terms with the competitive side of American builders!

This year’s class was the first to compete in the (soon-to-be) prestigious…


The Podlympics aim to allow the students to apply the knowledge they’ve learned in class to a tiny, tiny, tiny, Passive House structure, where each section coincides with lessons learned in class, red flags they must catch, and design flaws they must recognize that will negatively affect their structure over time.

Meet the Pod Teams…

The rules of the game…

The pods have the same net volume, even the Code Pod. The only difference is that the Code Pod complies with the 2015 IECC code, while the Passive Pods comply with the international Passive House standard requirements for “Cool, Temperate Climate” (similar to US Climate Zone 5). These code standards apply to things like U/R Values of assemblies, thermal bridge requirements, air sealing, and window types. (For example, the Passive Pods all have high performance Passive House certified windows, whereas the Code Pod has a standard regulation, building code compliant window purchased from a local hardware and supply store).

Smoke Test

Since the volume of the Pods is too small to be tested with a real life Blower Door Test, we did some qualitative air tightness testing using an itty bitty fan to pressurize the volume and an incense stick emitting smoke, to see where any air leaks may have been.

Smoke testing Team FOUR.

The Passive Pod teams resealed problem areas, whereas the Code Pod was permitted a higher level of leakiness.

Infrared Test

We then tested out our Flir cameras to see if we could spot any thermal bridges (a metric that is not addressed in code, but very much a part of Passive House standards). The Pods have some deliberate thermal bridges designed in for participants to identify and address during the workshop throughout the week, so this was an opportunity to see if they caught them.

Unmitigated thermal bridge in Team CODE’s pod.

As to be expected, the Code Pod showed several unmitigated thermal bridges of concern. The Passive Pod teams were pretty pleased with their preemptive actions to avoid thermal bridges, based on what we learned in class.

Resiliency Test

Prior to this, each Pod had a 250W space heater installed, 4 pouches each of phase change material, as well as one temperature and relative humidity sensor. All Pods were then warmed up simultaneously, for the same amount of time.

We then wheeled the Pods outside and left them there overnight.

Lucky for us, the Rocky Mountains delivered, and it snowed all night long. The next morning at 7am, we checked the sensors to determine which of the Pods would emerge as champion.

(Everyone was pretty invested at this point… you can imagine the tension).

And the winner is…

Team TEZ (Passive Pod #1) by only 0.21°F!!!

Note: Y Axis shows °F Temperature. X Axis show minutes of time passed from turning on the heaters. Heaters were on for around 25 minutes.

Congratulations, Tom, Eric, and Zack. You shall be rewarded with silly Emu swag and worldwide respect. Team SEAMONT (Passive Pod #3) came in a close second. Team FOUR (Passive Pod #4) came in third. And Team TYDA (Passive Pod #2) came in last … but not totally last!

In general, the results showed how similarly their Passive Pods performed to each other when implementing a defined set of high performance criteria and standards.

Comparing them to the Code Pod was when the value of #BuildPassive really became evident.

20°F difference between Passive and Code…

…after one night in the snow! Had these been actual living spaces, with no ability to generate more heat throughout the night, the folks living in the Code Pod would be huddling together for warmth. Whereas the Passive Pods were still showing temperatures in the 50°s with no additional heat provided.

And this is only looking at the energy benefits of building Passive. Not to mention the improved indoor air quality and the assurance of moisture control over the life of the structure.

All in all, the Passive Pods were an excellent learning tool (and a wee bit o’ fun) to emphasize the importance of an integrated design/build process that leans heavy on research based science and defined standards to guide us as we build for the future.

We had a blast with this class, and encourage you all to join us for our next class in May!

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