En route to net zero energy building

Welcome to the inaugural blog series of PassivHaus! Here we’ll roll out project plans, important information, and updates of fellow passive house building fans on how our community is doing.

This blog is intended to share our endeavours as a company and community, with a focus in that special attitude we should all have towards sustainability: the mentality of achieving a sustainable future without compromising anything away from it.

PassivHaus is a development company that builds high comfort homes that are designed to achieve net zero energy status (and sometimes net positive!). We accomplish such high energy efficiency by following the Passive House building standard and by using photovoltaic cells to generate power for our homes.

We started this organization with the objective of strategically tackling our dependency on fossil fuels. In other words, we asked ourselves: What segment in the US consumes the most energy? By answering this question, which by the way, that segment is residential (1), we knew that all of our efforts are going to be committed to 1) optimizing the energy consumption of buildings and 2) powering buildings from renewable energy sources.

The next question: If single family housing is the segment that consumes most energy, where is that energy coming from? Unsurprisingly, it turns out that the grid that fed homes in the US in 2016 sources its energy in the following fashion (2):

  1. Natural gas = 33.8%

  2. Coal = 30.4%

  3. Nuclear = 19.7%

  4. Total renewables = 14.9%

    1. Solar = 0.9%

  5. Others: 0.3%

Then, it was loud and clear. To make an impact and reduce the mine-and-burn energy format, we must build net zero energy homes. Our mission is set: to accelerate the adaptation of energy efficiency construction principles by building compelling and affordable net zero energy buildings.

Our mission is set: to accelerate the adaptation of energy efficiency construction principles by building compelling and affordable net zero energy buildings.

A net zero energy building is such one that generates at least all the energy it consumes (more generation than consumption would be net positive). In our research, the passive house principles are the best pathway to achieve zero energy status. Although there are other building standards, such as LEED and EnergyStar, these focus on other categories of sustainability (such as water preservation for LEED) or strive to just optimize energy efficiency in a marginal sense.

Passive House principles were designed under the assumption of “maximizing your gains and minimizing your losses” (3), striving to isolate the indoor environment from the cold/hot outdoor climate. To achieve this, designers and builders should focus on the following principles:

  1. Continuous insulation: thick insulation throughout all rooms of the house

  2. Airtight envelope: preventing the filtration of indoor conditioned air to the outside

  3. Solar heat gain: utilizing the heat provided by the sun to warm the house

  4. Heat recovery system: allowing new incoming air and filtered in-house air circulation

This four principles altogether assure that houses decrease their heating energy load by up to 90% and overall energy load by up 75%. These two new efficiencies are affected by multiple factors, such as building type and size, climate type, availability of high performance materials like doors and windows, and others. By far, climate is the most important factor, determining the on-site orientation of homes and even the necessity and size of an HVAC system.

When the Passive House principles were developed in Germany, the weather was a constant variable when measuring the energy performance of passive house buildings. When architects and builders started building passive houses in multiple cities in North America, they realized that certain hard requirements (such as air changes per hour and peak loads) would either under/over estimate the overall performance of the buildings (think about a passive house in Southern California and another in Toronto).

To successfully adopt the passive house principles to all weather types in North America, in 2015 the Passive House Institute of the US, PHIUS, developed a weather map that specifically describes weather types in all areas of the US and Canada. This tool, PHIUS+ 2015, helps designers and builders adjust and rate their projects with very specific performance targets that otherwise would have been rated under the one-size-fits-all performance target.

If Passive Houses are so great, why are all houses not passive? For now, the short answer is that this is such a recent development in homebuilding technology and it has been cost prohibitive to do in the past. To put it in perspective, just in 2013, there were just 90 certified passive house buildings in the US; by 2015 that number increased to 500, and by the end of 2016 the new total was 2,000 (4). That’s a 19 fold increase in just 4 years. How cool, right?

In this blog, over the next few months we’ll talk about the homebuilding and construction industries, some of the factors that have discouraged passive house construction, the role of federal, state, and local governments, our company culture of no-compromise sustainability, 21st century urbanism, and other cool things like smart homes and new building technologies.

To wrap up, we want to invite everyone to stay on the loop while we finish working on our website and social media pages. We are currently in the design stage of our first housing development to be located in Cincinnati, OH. Stay tuned!


Ronald Vieira

Founder, PassivHaus


(1) = US Energy Information Administration
(2) = US Energy Information Administration
(3) = US Passive House Institute
(4) = Bullard, E 2017, 'Passive house', Salem Press Encyclopedia Of Science, Research Starters, EBSCOhost, viewed 22 May 2017