At Hoke Ley Architecture & Interior Design Studio, we believe that design has the power to transform lives. The buildings we create function as part of their environment and they can either work for or against it. When we’re designing a project, sustainability is one of the tenets that we keep in mind. In this day and age, it’s so important to consider our impact on the environment.
We were very excited to partner with Kala in building the first certified passive house in Kansas City, Missouri. Achieving Passive House certification was a welcome challenge and a team effort. On the blog this month we wanted to walk through parts of that project as a tool for discussing sustainability in design.
First: What is a passive house?
A construction strategy
“Passive House” is a construction concept that focuses on energy efficiency. The house (or any building) is passive in that it doesn’t have a large impact on the environment around it and in many ways works with the environment. The first priority of a passive house is energy conservation, rather than renewable energy sources like solar. It’s focused on conserving energy being used, not about how that energy is created.
Energy efficiency isn’t just about the environment. It actually impacts the comfort and affordability of a space as well. Passive houses keep energy costs low because the building is highly insulated and doesn’t lose energy. It keeps the inhabitants warm in the winter and cool in the summer and sustains the quality of indoor air.
Not limited to residential builds
Passive House is an international concept—there’s no one way to build a passive house because the details have to be adapted to the regional climate. Passive building isn’t limited to just single-family homes anymore either and can extend to apartments, office buildings, schools, and other non-residential projects.
It’s possible to build to Passive House standards, or at least toward them, without pursuing the official certification. Our goal with the Beacon Hill house was to pass certification standards and we did, making it the first certified passive house in Kansas City.
We sought certification through Phius. Not only does Phius require a passive house design verification, but they also have a stringent Quality Assurance requirement. Certification has to be completed by onsite Phius Raters.
Why seek certification?
Sustainable design is growing more popular in Kansas City. Achieving certification requires both a commitment to sustainability and quality that we can take forward into other design projects, even ones that are not certified.
Plus, participating in programs like Phius helps pay it forward to future designers as our project is now included in the Phius database. The more designers and builders that participate in the process, the better the standard can get as we build and share knowledge.
What are the requirements for a passive house?
There are 4 principles that form the foundation for passive building. The goal is to ensure the comfort and health of the inhabitants as well as a resilient, durable structure.
Thermal control is about keeping the inside of the building habitable regardless of the temperature outside. So, cool when it’s hot out, and warm when it’s cold out. Temperature control is where most of the energy usage in a building comes from.
Creating a well-sealed envelope around the building is important both for durability and energy savings. A balanced ventilation system will protect indoor air quality and prevent loss of conditioned air to the environment.
To prevent overheating, passive buildings need to control solar radiation, which is essentially how the sun affects the building. We strategically place high-performance windows to exploit the sun’s heat in the cooler seasons and negate it during the warmer months.
Choosing the right mechanical system is important to maintain vapor and moisture control; this helps keep the building safe and comfortable.
Where does passive building fit into sustainability?
Listen to Katie Hoke discuss sustainable design:
There are 3 parts that make up sustainable design. The first is reducing the energy usage of a building, which is what the majority of passive house building focuses on. Sustainable building also has to consider the materials being used and the design itself too.
In theory, you can build a perfectly passive house using non-sustainable materials. When we talk about acquiring materials sustainably, we mean using renewable sources that come from places with fair labor practices.
Designing smart is also an important part of creating buildings that have a more positive impact, or at least less of an impact on the environment. Designing smart means we’re not building too large or “overbuilding”. We’re designing to fit the building’s use.
The Beacon Hill passive house in Kansas City
Beacon Hill is a historic Kansas City neighborhood within walking distance of some of the city’s most popular attractions. It’s seen a renaissance in the last couple of decades; vacant lots have been filled with new housing and commercial developments.
We were excited to partner with the homeowners on this project because Beacon Hill is the perfect place for innovative, residential building. Passive building truly can be used in any environment, and it’s particularly necessary to consider the impacts that passive building concepts could have in our cities, where energy usage is already high.
As an architecture firm, our job is to be the quarterback behind the team building any project. We serve as the liaison between all parties to make sure that the project moves from design to building to functioning as seamlessly as possible.
Choosing a general contractor is a key part of any project. It made sense for us to work with Kala, because they are certified Passive House Consultants and have been for 10 years.
The project process
When we start any project we always begin with gathering essential information on the build site, but this is particularly important for a passive build. We need to pay attention to the way the sun moves across the space and other environmental factors that will impact the design.
Passive building starts in the design stage, because you have to plan for the rigorous energy efficiency standards. Everything is impacted, down to the shape of the structure and the materials used inside and outside.
Once the design is decided upon, the development phase is where we get to work with the client to really build out the interior of the building.
After finishing the design and acquiring the appropriate permits, it’s our favorite part of the project: building! This is where the sustainable aspects of passive building really shine.
High performance components of the passive house
Structurally Insulated Panel (SIP)
SIP wall assemblies are a prefabricated wall system and allows for greater efficiency when framing a project. The walls are created using machines and lasers, which results in more precise construction and can cover a larger space without joints or seams. All of this leads to greater air tightness and, as a bonus, quicker assembly.
No thermal bridge
A thermal bridge is created at points where there is a break in the insulation layer, meaning that energy is able to move more freely from inside the house to outside. Thermal bridges can weaken the durability of a structure by allowing moisture to build up, leading to mold. The second floor overhang on the Beacon Hill house presented a thermal bridge problem. Our contractor worked to come up with a precise and efficient solution to insulate and eliminate the thermal bridge.
Intello air/vapor barrier
It’s important to maintain air-tightness, but also to allow moisture to escape. When moisture gets trapped in the envelope of a building it can lead to problems with mold. INTELLO insulation works with the climate, its structure responds to the external temperature.
Hoke Ley is committed to sustainable design in every project.
Sustainability efforts may require more planning and costs in the upfront stages, but down the road it saves you more money on energy costs in the future.
While the Beacon Hill house may have been the first certified passive house in Kansas City, it most certainly won’t be the last. As architects and designers, we know it’s important to consider the sustainability of our projects. The buildings we create are going to be around for a long time and a lot of resources go into their creation.
Not every project has to achieve passive house certification, but using passive building principles in all of our projects has a positive impact on our environment.
Passive building isn’t just about the external environment, it’s also about ensuring internal comfort as well. Creating a space that people want to be in is an overlooked part of some sustainability efforts, it doesn’t matter how well designed the building itself is if people don’t want to use it and it gets abandoned after a couple of years.
Interested in adding sustainable building concepts to your next project? Schedule a meeting with Hoke Ley!
Here at Hoke Ley, we consider it a privilege to guide you through the process of creating a functional, sustainable, and beautiful space for clients from all over the Kansas City region. Reach out to us about starting on your project, and get excited! We can’t wait to work with you.