Passive House Model Gets Active Upgrade

Amber Plante for Zondits, July 16, 2015. Image credit: blickpixel

The passive house design movement toward ultra-efficient dwellings has been gaining popularity in the United States for years, and now it’s about to take a giant leap forward – a 250-foot leap straight up, actually.

Cornell University’s Cornell Tech applied sciences division is building the world’s tallest passive house: a student dormitory on the school’s futuristic Roosevelt Island campus that is set to open in 2017. The dorm, which will host 520 students per semester, will be 100% airtight and could reduce the city’s CO2 burden by 882 tons per year.

The idea behind the passive house model is simple: build an ultra-low energy structure that will maximize the natural heat, cold, and ambience of the surrounding environment to eliminate the need for traditional heating and cooling machinery to maintain comfortable room temperatures, thus drastically reducing energy bills and the building’s carbon footprint. Regardless of the outside temperature hitting a hot or cold extreme, the temperature inside does not fluctuate enough to necessitate traditional HVAC equipment. Fresh air is circulated in from the outside to do away with the stale, stagnant air while also greatly reducing the threat of mold typical with airtight structures.

The passive house movement began in 1988 in Germany (where it is known as “Passivhaus”) when designers Wolfgang Feist and Bo Adamson created the concept of an ultra-low energy home. The first prototypes were built and occupied in 1990, and in 1996, the Passivhaus-Insitut was founded in Germany. Since then, more than 25,000 passive houses have been built globally. These constructions are mostly located within German-speaking countries and Scandinavia, and they are not restricted to domestic dwellings; there are supermarkets, schools, and a few low-rise office buildings boasting the certification.

Back in the US, where it seems that bigger is always better, it’s no surprise that New York City will be leading the charge of introducing this technology on a larger commercial scale. Cornell’s towering new dorm will not only join other passive house projects going on around the country, but it will officially be the largest structure in the world to claim such astounding efficiency. The numbers make it clear: although the building will cost 5% more to develop because the design process is more complex, it will use up to 70% less energy than similarly sized buildings.

One challenge (and a possible stumbling block to expansion of the technology) facing the building of Cornell’s new dorm is the windows. Typical skyscrapers feature full floor-to-ceiling windows to maximize the tenants’ view, but sealing these windows to the passive house airtight standards is not an easy feat – if it’s even possible on such a scale. A double envelope (basically, a building inside of a building) would be necessary. The Cornell dorm has mitigated this by simply using smaller windows, but only time and the real estate market will tell if architects and prospective buyers will agree to reduce their precious (and expensive) views.

Another passive house property trying to make history is the retrofit of an existing building in Portland, Oregon: a 96-year-old, two-story office building near Cesar Chavez Boulevard could be the first US passive house retrofit in the country. As it stands, the second floor will feature the full retrofit through the installation of triple-paned windows, extensive insulation, a recirculation engine in the basement for water and air – and a $15-per-foot increase in construction costs. The first floor features a restaurant that will not be retrofitted to the passive house certification but will be modernized to more general energy efficiency standards.

Although great technology comes with higher costs, experts are certain that these buildings will feature complete paybacks that make them well worth the initial investments. If the Cornell dorm proves to be a successful trial in the commercial high-rise application of the passive house energy efficiency model, its blueprint will literally serve as the blueprint going forward for new commercial buildings from coast to coast. That 882 tons of CO2 will be multiplied beautifully as the revolution grows.

The future of building construction, it seems, could truly be upon us, and there’s nowhere to go but up.

For more information on passive houses, please visit