Passive House: Exploring the Potential for Net Zero and Energy Positive Buildings

Andy Allwine, AIA, recently attended the 14^th annual North America Passive House Conference, sponsored by Passive House Institute US. The conference, titled “The Profitable Blueprint for ZERO,” included pre-conference education sessions, keynote talks and two days of education sessions all centered on passive building techniques, detailing and marketing, building science, carbon neutrality and safe building materials. We asked Andy about some of his take-aways from this conference.

What is a Passive House?

A passive house is a building with an airtight, well-ventilated, highly thermally insulated enclosure that reduces the external loads on the building and allows for a smaller, more efficient mechanical system. These factors also happen to make for a more durable building that requires less maintenance, provides a higher degree of health and comfort for occupants and helps mitigate the effects of climate change through radically reduced energy consumption and global warming potential. Almost any building type, use, size, and climate region can achieve passive house standards, including retrofit conditions. In my option, almost all of our projects would be worthy candidates to apply this standard.

According to the Passive House Institute, the term passive house is something of a misnomer as the approach is increasingly being applied to multifamily apartment buildings and large scale commercial buildings as well. As a result, the term passive building is gradually coming into more common usage, as it’s a more accurate term than passive house.

What is your interest in Passive House?

My interest was partially project-specific research and partially general information gathering.  We currently have a client interested in passive certification so we wanted to learn everything we could in advance of that project design.  However, I was equally interested in the value and viability of passive standards for all of our work.   Recognizing that college and universities have been early adopters of this standard to help accomplish their on-campus sustainability goals, my objective was to attend sessions that focused on those types of spaces that have utilized the standard.

This conference reinforced my passion for helping RLPS continue to move towards a more high performance building design standard. My next step in this journey will be taking the Certified Passive House Consultant training this year.

What are the cost implications for Passive House?

This year’s overarching topics were the push to net-zero/net-zero ready buildings and reducing or eliminating the cost premium for building to passive house design standards. Much of the premium seems to already have been reduced to negligible levels in markets where passive design has been practiced for a number of years and contractors are familiar with the standard.  Also, as more large-scale window and door manufacturers bring high-performance products to market, economies of scale are expected to further drive down costs.

Ultimately, I believe that the use of passive house principles will lead to healthier buildings that are less expensive to maintain and operate for our clients. It seems likely that this level of high performance design and construction is going to continue gaining ground—either through code mandate, market demand or a combination of both, so it just makes sense for the RLPS team and our clients to understand the benefits and start implementing the principles sooner rather than later.

What are some of the steps we can take now for highly efficient design?

Much like other sustainable design and healthy building initiatives, the best results are achieved through the combined efforts our architects with the engineers and general contractor team members.

A few of the steps we can explore immediately include:

-More insulation, less air leakage and smaller/better mechanical systems (Passive House basics).

-Cost efficient design and construction methods:  finding savings opportunities during the design process that can be reallocated for high performance design, better finishes and other design ‘extras’.

-Thoughtfulness in materials selection – avoiding toxic materials, understanding environmental impact, and reducing carbon emissions.

We’re already doing all of this to a certain degree.  Passive house is just about prioritizing the long-term value of highly efficient design when evaluating the options and making the tough cost decisions that occur on every project.

What was your big take-away from the conference?

Buildings, and especially building envelopes, that are built or renovated today are meant to last 30, 50, or in some cases even 100+ years. That means that the consequences or benefits of any decision we make today will be around for our lifetime and for future generations. A humbling thought to keep in mind throughout our work, especially given the current worldwide climate trends.

Passive House by the Numbers

The first Passive House (Passivhaus) residences were built in Darmstadt, Germany in 1990, and occupied by the clients the following year.

In the United States, the concept of passive design was first implemented by Katrin Klingenberg in 2003 when she built a passive home prototype named “The Smith House” in Urbana, Illinois

In 2019, Park Avenue Green, a low-income housing building in New York, became the largest certified Passive House in North America.

Since the release of the PHIUS + 2015 Building Standard, more than 1,200 projects and 1.1 million square feet have been certified across the United States.

Currently, a passive house typically costs about 5-10% more than a conventional home.

Larger projects benefit from the economy of scale: a multifamily passive building typically only costs 0-3% more than a building built to an Energy Star baseline.