What is Passive House design?

Energy efficient and sustainable building has come a long way recently, with more and more home buyers interested in going green. Not only can an energy efficient home be more comfortable to live in, but it can really reduce energy costs. Passive House design is a particular kind of architecture that is laser focused on energy efficiency. Given the variety of green building certifications that are available, including LEED, people could wonder, what is passive house design?

To answer this question, we turn to Stephanie Bassler, and expert in this type of architecture. Over the last 12 years, Stephanie and Peter Reynolds, co-founders of North River Architecture & Planning, PC, have collaborated on many diverse projects in the Hudson Valley and beyond. All of their projects are distinguished by their energy efficiency, their sensitivity to local context, to the community and their client’s highest achievable goals.  An expert in sustainable and net-zero building design and a Certified Passive House Consultant, Stephanie brings a whole-systems framework to the drafting table, with a particular interest in emerging high-performance building technologies and the challenges of adaptive reuse of historic structures. She is Vice President of the Passive House Alliance – Hudson Valley chapter and is currently advising local municipal governments on incentivizing energy efficient construction. Stephanie earned her Bachelor of Architecture from Rice University and is licensed to practice architecture in New York and New Jersey.

What is Passive House design?

“Passive House” refers to a construction standard with rigorous requirements for insulation, airtight construction, high-performance windows, balanced ventilation, and minimal heating/cooling systems.

While following a familiar “passive solar” principal, popular in the U.S. during the 1970s energy crisis, of south-facing window orientation and making use of solar energy to passively heat buildings, the modern Passive House technique guarantees healthy indoor air and has none of the air quality and durability problems that were found in that type of construction 40 years ago.

How does Passive House design differ from other sustainable or energy efficient options, such as LEED, etc.?

Passive House design focuses on the energy efficiency of the building itself, unlike LEED, which addresses a broader range of environmental impacts, including access to transportation, use of recycled materials, and construction waste management.  Those additional criteria can still be priority in a Passive House, but the Passive House standard does focus much more tightly on energy use reductions.  By devoting the limited resources of any project to upgrades to what we call the “shell”, or a very good enclosure, the goal of Passive House is to make highly efficient construction techniques accessible to the widest possible range of customers.

What are the major benefits of owning a Passive House?

Passive House homeowners can expect extremely low energy bills, or zero energy bills if solar panels are added and the house becomes Net-Zero!  These homes are very comfortable, maintaining even temperatures and fresh air ventilation year-round.  Also, the principles of solar orientation result in homes that make emotional sense, with living spaces bathed in sunlight on winter days, and smart shading keeping the interiors cool during the summer.

With Passive Houses, we find ourselves starting every project with a regional, and in some ways more traditional approach to design that guides the siting and orientation of the building, the interior layout, and locations of windows and doors for year-round comfort.  All of this can be done with a modern sensibility about living spaces and architectural design.

What else should people know about Passive House as an option?

Whether buying or building, one should consider the lifetime energy costs of the home in addition to your mortgage and other ownership costs.  It’s cheaper during the course of a 30 year mortgage to live in a Passive House, whether it’s a renovated home or new construction.  In addition to cost savings over time, Passive Houses are more comfortable, healthier, and resilient to a changing climate.

What are the cost considerations with Passive House vs. standard construction?

We have seen about a 10% increase in costs for Passive House design as compared with standard code-compliant construction.  This cost is returned easily within the span of a 30 year mortgage, and usually within 7-10 years, by virtue of substantial energy savings every year.

What countries are adopting Passive House design the most, and what about the US?

The current practice of Passive House design began in Germany in the early 1990s.  As expected with that area of origin, it is quite widely used in Germany, Austria, and is also very popular in the United Kingdom.

Passive House construction in the United States has been growing exponentially, but we do have a lot of work to do to expand awareness and adoption.  While our practice’s focus is on single-family Passive House design, multifamily housing is another growing market for Passive House worldwide, as it is the most cost-effective way to build energy-efficient housing.  Many U.S. projects of that type have been completed recently, or will be soon.

What geographies or climates is Passive House design most suited for?

The Passive House Institute of the United States, or PHIUS, created a climate-specific Passive House standard in 2015 that encourages Passive House construction in all North American climates.  Climates with moderate-to-high heating requirements in the wintertime are very well suited to the Passive House standard, which is evidenced by the majority of Passive House projects in the U.S. being built in the Northeast.  Even so, I would encourage any architect, builder, or homeowner to try to build as close to the Passive House standard as possible:  The energy savings, comfort, durability and climate resiliency just make good sense, no matter where you live.