Colorado: our work ties become permanent


With Mariana currently involved full time with Natural Capitalism Solutions and AE Building Systems, our professional ties with Colorado are now solid.

This allows us to have experience in highly efficient buildings on both sides of the Atlantic, with some initial interesting considerations.

We finally had a chance to visit Andrew Michler’s passive house, in the mountains near Fort Collins. Almost as planned, a snow blizzard blocked us there, making the visit very interesting, because it allowed us to experience the house under an extreme weather event. We’re going to cover it with a specific article.

01 house

We visited Advantage Architectural Woodworks, in Colby, Kansas. They are interested in starting the production of high quality, wooden frame passive house windows. In the middle of the prairie, we were impressed by their obsession for details and their will to innovate.


The meeting with Busick Glass, in Denver, allowed us to visit one of the last remaining independent glass manufacturers in the area.

Single seal glass

This visit highlighted major differences between Europe and North America, in terms of production and expected durability of IGUs. The main difference lays in the sealing of the units.

IGU sealants in EU and US

The type of sealant is of primary importance for the durability of the IGU, and to keep the noble gas inside it. We’re going to cover this topic in depth, in a specific article.

We had the pleasure to meet Shelly Miller, professor of indoor air quality at CU Boulder. With her, we had the chance to discuss indoor air quality and mechanical ventilation, which represent the core of the original concept of passive house.

CU Boulder

Prof. Miller directed Stefano Brunelli, a visiting Italian student from University of Trento, in the analysis of the IAQ in Andrew Michler’s passive house. They monitored several indoor pollutants (some due to the construction process, some to people activity), and the use of mechanical ventilation to remove them.

While celebrating the new year in a cabin at over 3.000 m (9.500 ft), we also had the chance to appreciate how building physics takes no vacations. The windows were of such a low quality, that every morning we’d wake up with an ice layer along the inner perimeter of our bedroom window.

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To try and bring our European feedback to North America, we submitted a presentation proposal for the 2016 NAPHN Conference, scheduled in New York in June. Fingers crossed!