Why Build Different?
Our climate is becoming more extreme and our world is warming. New weather patterns are emerging due to climate change, adding stress and new concerns about the resiliency of our built environment. Therefore we need our buildings to drastically reduce their carbon footprint (to decrease energy use during operation as well as be constructed of lower carbon intensive materials when manufactured), to be durable, to be comfortable, and to be healthy places for people. Fire resistance, stay-in-place resiliency during power outages, and low energy costs are benefits of Passive House design.
Why Passive House?
Designing buildings to “meet Energy Code” is not enough to reduce energy use to significant levels. Your local energy code was approved in a slow moving legislative process that is a mix of science + politics + industry lobbying. It is the bare minimum required to legally build.
Following the Passive House method is different. The standard was created by a scientific institution in Germany in the 1990s and has decades of data with proven results. It is firmly grounded in building science and physics, is climate + site + project type specific, applies to all building types, and can fit any architectural style.
[Note, “Passiv Haus” in German refers to the “Passive” systems approach of the method, meaning they keep warm passively not relying on mechanical or active systems such as heating systems or solar panels to keep a building comfortable and operational. This is equivalent to choosing the right coat for hiking in Minnesota and not grabbing too thin of a jacket. “Haus” in German refers to “Building” in general and is not a residential home.]
That is the Yarrow Architecture difference.
At Yarrow Architecture, we use a combination of the latest climate models using the Passive House method to recommend the correct “coat” that will keep people comfortable indoors and energy use low. We pair that High Tech understanding with Low Tech tried and true vernacular technics. The result is building design that is exciting, high performing, low-carbon using, comfortable, healthy, and people-centered. We believe low carbon buildings and healthy living should be mainstream practice.
Building Better Prepares You for a Resilient Future
Build Better Today
The 5 Classic Principles of Passive House Design
01 . Continuous Insulation
A continuous layer of insulation wraps Passive House buildings, keeping them warm in the winter and cool in the summer. Passive House designers also harness this insulative layer to prevent condensation inside the building and its assemblies.
In the Upper Midwest: continuous insulation can be rigid boards placed on the exterior sheathing (such as wood fiber or foams) or an I-Joist / Larsen Truss applied to a structural 2x wall and filled with dense pack cellulose or timber fill insulation. Passive House is not prescriptive in its approach, so we review the best methods to get the right amount of insulation with cost and available labor always in mind.
02 . No Thermal Bridges
A thermal bridge is any building element that allows heat or cool to bypass a building’s thermal barrier. It’s like a hidden thief of thermal energy, undermining performance and durability.
In the Upper Midwest: continuous insulation should be applied in a way to eliminate thermal bridges. Careful attention is paid at places of transition and penetrations. Architectural elements should not create thermal bridges, such as no beams that are exposed inside and outside a structure. Masonry chimneys are a huge thermal bridge.
03 . Airtight
A Passive House building’s airtight layer is like a windbreaker, stopping air from penetrating to the inside. Establishing this unbroken air barrier is central to Passive House performance and durability.
In the Upper Midwest: continuous insulation is your winter coat. The airbarrier is your gortex. Both are important to regulate moisture and thermal comfort.
04 . High Performance Windows + Doors
With each window and door opening we make in a Passive House building, we are essentially punching a hole through an advanced wall assembly and its airtight, weather-resistant, and insulative layers. So, the performance of the windows and doors that go into those holes, and how well we tie them into the surrounding wall assembly, is mission-critical to maintaining the integrity of the Passive House building envelope.
In the Upper Midwest: Triple paned windows are mandatory. The quality of those windows and doors also comes down to the insulative and airtightness properties of the frames and the seals. And you’ll enjoy siting right next to your window on a cold, snowy day like you never thought possible.
05 . Fresh Air through a Heat Recovery Ventilator
The delivery of filtered, fresh air with heat recovery helps make Passive House buildings havens of clean air and energy efficiency. HRVs (heat recovery ventilators) and ERVs (energy recovery ventilators) are “balanced ventilation” components that supply a continuous stream of fresh air to living spaces while simultaneously extracting stale air, odors, and indoor pollutants from kitchens and bathrooms.
In the Upper Midwest: ERVs are needed in most applications. These units can typically be equipped with excellent filters, including HEPA filtration. The Upper Midwest is experiencing more days of allergens and wild fire smoke. The airtightness and filtration systems of a Passive House help keep smoke infiltration much lower than its code built neighbors.
Additional Criteria for Passive House Buildings
06. Shading:
Careful shading of windows to optimize solar gain while avoiding too much heat gain or glare.
07. Orientation + Form:
Building orientation and form are fundamental design decisions that set the stage for how easy or difficult it will be for a building to achieve Passive House performance. Passive House design starts at the very beginning, and is not an element to be tacked on later in design.
08. Daylighting + Solar Gain:
Natural daylighting and passive solar heat gain can provide energy “freebies” to Passive House buildings. Often “Passive House” is misunderstood as “Passive Solar”. Passive Solar is an element of consideration, but not the whole picture.
09. Moisture Management:
To ensure building durability, Passive House designers study how heat and moisture will behave in building assemblies in a given climate, and create designs that manage that behavior to avoid condensation risk and bulk water intrusion.
10. Efficient Water Heating + Distribution:
Because Passive House buildings dramatically reduce heating energy use, another source of energy consumption—domestic hot water—becomes a more conspicuous part of overall energy consumption. Energy-efficient water heating combined with efficient water distribution reduces this slice of the energy consumption pie.
