Passive house cost estimates vary based on design choices, project square footage and project type. This article examines six estimates of passive house cost and the factors affecting return on investment (ROI).
What is Passive House?
Passive House is a rigorous, energy efficient design and construction standard for commercial and residential buildings.
Passive houses are designed, constructed and certified to a “Passive House” standard, as described more below.1
Buildings certified to Passive House standards are up to 90% more energy efficient than buildings designed only to code.
Passive buildings combine super-insulated, air-tight building envelopes with energy recovery ventilation (ERV) systems and optimal orientation to leverage warmth and light from the sun.
The result is a building that maintains a relatively constant internal temperature of around 70 degrees, without the help of conventional heating or cooling (HVAC) systems.
Passive House Cost: 6 Estimates
What does a passive house cost to build? That’s a tough question because, after all, what does a car or a bag of groceries cost..?
The answer of passive house cost depends on what goes into the final product.
While most passive house certified buildings are residential, passive house design is increasingly being applied to larger commercial and multi-family buildings. The result is that builders have A LOT of flexibility when they build to passive house standards. Passive house certification requires compliance with only the performance requirements (described below).
Of course, because every house or building is different, the ultimate cost will depend on your personal tastes and your definition of quality. Your passive house may boast super-high end finishes, luxury appliances, and other bells and whistles… Or it may be built very modestly.
The cost of a passive building varies by square footage, climate, finishes and design complexity. However, the premium for going “passive” seems limited to the super-insulated nature of the building’s six sides (four walls, roof and floor).
The following are six (6) estimates of the passive house premium from five (5) passive house builders:
While passive house cost premium estimates from experienced builders vary from 7-15%, it is debatable whether this is actually a premium.
Perhaps a better perspective on passive house cost is to view passive house design as an opportunity for a return on that investment over time.
5 Factors of Passive House Cost to Consider:
- Passive House = Investment in an asset: The “premium” for passive house should be around 7-15%. That said, this added expense up front is really an investment made by the owner and will provide a return on investment (ROI) in the form of energy savings and reduced maintenance costs over the life of the building.
- Prefabrication reduces construction time: Entire prefabricated passive homes and prefabricated passive building components, such as wall assemblies, can reduce labor costs associated with construction. Prefabricated assemblies are increasingly available in the U.S. from companies such as Ecocor, Unity Homes and Bright Built Home.
- Building supply cost transparency: As passive house design gains in popularity, transparent pricing and increased availability of core building components can mean more savings. Energy recovery ventilators (ERVs), heat recovery ventilators (HRVs), ductless mini-splits, triple glazed windows, breathable building membranes and other components are increasingly accessible through online passive house building supply companies, such as Four Seven Five.
- Reduced operating costs: Passive buildings can use up to 90% less energy than conventional buildings. Because of their focus on efficiency, passive buildings are ideal for zero energy building (ZEB) design. ZEBs use solar photovoltaics (solar panels that produce electricity) to generate as much energy as they use. As a result, net energy costs for operation of Net Zero properties should be close to zero.
- Reduced insurance cost: Your insurance company should be aware of the benefits of passive house design and the potential lower risk profile of your passive building. The result should be an opportunity for property insurance and/or general liability (GL) premium credits for your passive building construction and operation.
Passivhaus – Passive House History and Requirements
Dr. Wolfgang Feist and Professor Bo Adamson created the first passive house standard, called Passivhaus, in the 1980s. Soon after, they founded the Passivhaus Institute in Darmstadt, Germany to certify passive buildings.
Passivhaus requires strict adherence to the following performance specifications:
- Space Heating/Cooling Demand: Not to exceed 15 kWh per square meter of net living space (treated floor area) per year or 10 watts per square meter peak demand (with some additional allowances for dehumidification in warmer climates).
- Renewable Primary Energy Demand: Energy used for all domestic heating, hot water and domestic electricity must not exceed 60 kWh per square meter of treated floor area per year.
- Airtightness: The building envelope must not exceed 0.6 air changes per hour at 50 Pascals pressure (ACH50) as verified by an on-site pressure test.
- Thermal Comfort: All living areas may not be over 25 degrees Celsius (77 degrees Fahrenheit) for more than 10% of the hours in a given year.
Critics of German Passivhaus fault it for its “one-size-fits-all” approach to certification, regardless of building location, climate and local energy costs…
Consequently, they believe this rigid approach results in occasional mismatching of annual heating, cooling and dehumidification demand.
PHIUS – Passive House U.S. Standard
In the early 2000s Americans Katrin Klingenberg and Mike Kernagis established the Passive House Institute – United States (aka PHIUS).
The Illinois-based non-profit organization promotes passive house principles throughout North America and supports a growing community of passive building professionals with research, education and events.
Most noteworthy, PHIUS is working to improve upon the German passive house standard. In collaboration with the Building Science Corporation, PHIUS launched PHIUS+ 2015, a more ductile approach to passive house design and construction.
PHIUS+ may be the optimum balance of passive house cost and efficiency… The new standard provides tailored passive house guidance for over 2,000 geographic locations in North America according to:
- Local climate
- Source energy
Consequently, PHIUS+ buildings consume 86% less energy for heating and 46% less energy for cooling, compared to code compliant buildings.
What Impacts Passive House Cost?
As mentioned above, there is no one factor determining passive house cost… But passive houses still carry a 7-15% premium…
What is this premium attributed to?
The premium attributed to Passivhaus or PHIUS+ may be rooted in five core passive design strategies:
- Continuous Layer: A layer of super insulation is present across the entire building envelope with zero thermal bridging. Insulation must perform to resistance values (R-Value) R20 = basement, R40 = four walls and R60 = roof.
- High-performance windows and doors: Triple paned, airtight windows and doors limit heat loss while capturing daylight and passive solar energy. Windows will be “low-e”. This prevents unwanted solar heat gain. All windows and doors will perform to a U-factor of no more than 0.14.
- Thermal Balance: Balanced heat, coolness and moisture recovery is managed via energy recovery ventilators (ERVs) and/or heat recovery ventilators (HRVs). Traditional HVAC systems are not necessary. The building uses minimally sized, efficient mechanical space conditioning systems to balance heating, cooling, moisture and heat recovery.
- Blower door tested building envelope: The airtight nature of the building envelope prevents air outside from entering the building and prevent loss of inside conditioned air. Passive house design must meet 0.60 ACH50 (o.6 air changes per hour at 50 Pascals).
- Optimal orientation: The building leverages the sun’s energy for heating during cool months and minimizes overheating in warmer months.
As mentioned above, a passive house may cost more, but it should perform better than a conventional home or building.
While some Passivhaus ascetics object to the changes brought about by PHIUS+, more extrospective proponents of energy efficient building have heralded PHIUS+ as the locus classicus of passive house design…
Indeed, looking ahead to the future of high performance building, PHIUS+ may bring about a more thoughtful, iterative process in residential and commercial passive building development.