Passive House

When Passive House design entered the marketplace in the 1990s, it was conceived for single-family homes to make them more energy-efficient and comfortable for occupants; the focus was isolated to the confines of that building.  As Passive House design has expanded and gained exposure, more and more owners and developers are considering Passive House design practices and techniques for larger-scale commercial projects, from municipal and industrial buildings to high-density affordable housing and beyond.

Passion for Passive House

Integral Group Associate Principal and Certified Passive House Consultant, Stet Sanborn recalls his own introduction to Passive House in 2007, “I got interested in [it] back when I was still practicing architecture, and it was something that we had really progressive clients asking for, and that ultimately lead to me going through the full training to become a certified passive house consultant.  From there it’s been more and more an obsession with building enclosures, performance; where architecture and engineering meet.”

Scott Ghomeshi, Senior Mechanical Designer and Passive House consultant out of Integral Group’s Vancouver office was introduced to Passive House on the Hornby Island Fire Hall project, “The project required the team to design a resilient building for a small volunteer fire hall with a tight project budget of $1.9 million. As a design team, we understood that allowing for the building’s design to utilize passive design principles through the use of a robust and high performing building envelope meant that we could specify simple and cost effective solutions that could help achieve the project’s intent. We were able to model the building’s design through the Passive House Planning Package (PHPP) and provide insight into how differing components made an impact to not only year round energy use as well as impacts to sizes of mechanical systems and occupant comfort.”

Integral Group Building Performance Engineer, Stefan Gracik, was so inspired by Stet’s passion for Passive House, last year he completed his own Passive House consultant certification. Stefan added, “I definitely jumped on [becoming a Passive House consultant] because I enjoy working on envelopes, building really good building envelopes and building insulation performance with Stet.  I really like the idea that we can have our mechanical engineers not do less work, but reduce their scope of the project and put more focus into insulation, windows, good solar strategies, because that’s a much more sustainable design.  It requires less maintenance and is sustainable in a way that will last a lot longer than a really fancy HVAC system.”

Passive House as Best Practice

“Mechanical systems break and typically last 15-20 years,” Stet adds, “A really good building enclosure is a 50-75 year life so if you can find ways to put that same money you would have put into your fancy mechanical system into making a better building, there’s a long-term better value for the client and lower energy use.  It’s a win-win.”

“[Clients] are not used to thinking about it that way,” Stet continues. “They think ‘Oh that’s another added cost.’ But if you walk it through all the way to the end of the process it’s usually a cost transfer.  Coming from the [NAPHN] conference and going through a bunch of presentations we’re seeing first cost “premiums” from none to 7%, but that 7% number was a few years ago, and now those projects are coming in at-cost.  No cost increase, just a better design.”

Scott added, “Passive House’s envelope-first approach asks us to consider the following: instead of throwing technology and complex mechanical systems to counteract what is often a weak envelope, we are instead asked to consider a well-insulated and airtight envelope has the ability to reduce the buildings heating/cooling need tremendously to the point where the only load to consider is your ventilation. At Integral Group, we’ve excelled at convincing our clients to consider this approach in the past; it may have not been called the ‘Passive House Standard,’ but it is what we consider to be good engineering practice that fits with Integral Group’s Deep Green Engineering design ethos.”

Stet and Stefan were featured panelists at the 2017 North American Passive House Network Conference in Oakland in October.  Using Stefan’s modeling and analysis research and experience with Title 24 code writing combined with Stet’s breadth of Passive House design experience, the pair conceived two innovative presentations: The New Power Couple: Passive House and the Renewable Grid and Heat Pumps are Your Friend: Serving Your Mechanical Needs and the Needs of Your Power Supply.  Both sessions examined Net Zero Energy and energy storage standards, and offered new innovative solutions on how Passive House techniques can improve grid stability, and help correct the over-application of renewable energy.

“In the New Power Couple [presentation] we were really investigating this idea about the grid stability and Passive House, because we’re moving to this renewable grid, it’s a different grid than we used to have, it’s not fossil fuel-based, we can’t just shift all our load to the night. Demand response is going to be different. There are all these things that are going to change about it,” Stet explained. “I fundamentally believe that [the Californian] ZNE by 2020 target is alone a bad goal. It provides the incentive in the wrong place. It’s incentivizing us to get to Net Zero without addressing efficiency. PV and batteries are great for temporary load shifting and they’re going to help, but they are not going to ultimately make a building more efficient.  That’s where I think the new power couple is Passive House and ZNE because of this limit on how much energy you can use it forces you to go down this really rigorous path of efficiency measures before you hit ZNE.  Before you add PV, your building has to be anywhere from 20-90% better than what we are building now, and it forces buildings to hit this max energy use regardless of where you are.  So if you’re in a more extreme climate your building should be, by definition, a better building.”

Bridging the Policy Gap

Addressing gaps in energy codes goes hand in hand with Integral Group’s focus in renewable energy application in design, always looking for the next phase in sustainable built environment, and seeking out the technologies that will have the biggest impact.  It all comes back to good energy policies.  Stefan regularly consults with the California Energy Commission to make recommendations for the Title 24 Energy 2019 code cycle review.  Dave Ramslie, Principal, Sustainability + Research in Integral’s Vancouver office recently helped spearhead the Three For All campaign, a coalition of sustainable firms and organizations pushing for better energy efficiency standards in British Columbia via the BC Energy Step Code.

These policy changes in energy codes are leading the way policy makers incent developers to make more efficient buildings.  Stet cites even the most basic changes in affordable housing funding criteria in Philadelphia, Pennsylvania, where “[The State] added Passive House as one of those criteria and gave it ten points. Within a two year period they went from having no one submit a Passive House project to in the first year a handful of projects, and last year over half of the projects submitted were going for Passive House [certification]. It was a change that small that…completely changed the game.”

Stefan adds, “What I think is great about Passive House, is that it’s changing the game for energy codes. Typical energy codes now use this fictitious energy model that that says ‘this is the code building’ and then you have your energy model for your building and you say ‘this is our building’ and it has to hit the code building or better by a certain percentage. It’s a strange way of doing it.  It’s not always associated with reality.  Passive House as a standard is pushing people to look at the total energy they’re allowed to hit for their building and they need to model it to that energy use, so there’s no fictitious code.  If you want to set energy standards for your building, that’s definitely the way to do it. It’s causing a renaissance in energy codes where British Columbia and a lot of the other provinces in Canada are moving their energy codes to being, ‘Ok your building can only use this much energy per square foot.’  They even go farther saying, ‘you can only provide this much heating in your building this year’ so you can’t just get away with the bandages of efficient HVAC systems you actually have to build a better building.”

Other more global considerations about grid stability are also a concern.  As more and more photovoltaic paneling are added to buildings, power plants are seeing a dangerously high influx of power flowing onto the grid around mid-day when solar energy is plentiful, and then a sharp decline when the sun goes down and energy usage spikes.

Stet added, “[P]utting all this PV on is going to cause problems and those problems are going to come back to us as cost.  Whether they have to build peaker plants or have huge battery systems on the grid to help with fluctuations on the grid that’s all going to come back to the consumer as a cost, and I fundamentally think that the CEC needs to see this information that we’ve presented and if we’re heading to ZNE by 2020 and 2030 then we need to redirect incentive funding to actually do a much deeper dive into efficiency measures and stop looking at the individual measure pay back on costs because that’s not what we’re arguing about, we’re looking at where we are collectively going and is our grid going to be able to survive.”

The Future of Passive House

The development and further implementation of Passive House will depend on “improved knowledge sharing and a guide surrounding precedents [to] help catalyze uptake by stakeholders, as this is often a hurdle design teams encounter,” Scott concluded.

It’s clear the Passive House movement has gained momentum in recent years. The application of passive design continues to expand and accelerate across a wide range of building types, sizes and uses, influencing both new construction and renovation projects, and touching all building features from façades and envelopes to overall architectural style.  The common thread creating the biggest shift in design mindset is education and policy guidelines that inform and incent future system choices over traditional systems.