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Is Passive House Still Relevant, Over 30 Years Later?

As Passive House Enters its 4th Decade; Is the Standard Still Relevant?

The world’s first experimental Passive House building was completed in 1991 in Darmstadt-Kranichstein, Germany. The four passive dwellings were designed by Swedish engineer Bo Anderson and the physicist Wolfgang Feist, who went on to establish the Passive House Institute. Feist still lives in one of the Darmstadt passive houses today.

The four-unit multi-family building envelope was constructed with thick EPS insulation and triple-glazed low-e argon windows, was free of thermal bridges and airtight. A heat recovery/ventilation system delivers fresh air to the rooms and living spaces. After three decades, there is still a greater than 90% savings by energy efficiency, and everything is working as originally intended. The four units each passed the blower door test for airtightness, and insulation R-values and windows and door U-values have not changed.

After 25 years, the building was fitted with a photovoltaic system to generate its own electricity. While not net zero, the original Passive House building only draws energy from seasonal storage and the grid five months of the year.

Thirty-one years later, the building continues to deliver optimal comfort, fresh healthy indoor air, a reduced total cost, and a sustainable solution for protecting the climate, resilience and durability.

The 25th International Passive House Conference was held in Darmstadt/Wuppertal, Germany in October 2021. There were about 700 participants and Passive House celebrated its 30th birthday. (The 26th International Passive House Conference will take place in Spring 2023.)

One of the key topics at the conference was the upgrade of older buildings to meet climate and carbon objectives. When it comes to home renovations, in terms of total costs, the most economical option has been to implement the EnerPHit Standard which represents the Passive House Standard for existing buildings. Wolfgang Feist warned that “without significantly greater commitment on the part of the governments, there will be very little progress in energy efficient construction of buildings.

Passive house design is simple, dependable, and durable

With 12 – 18 inches of insulation, optimal placement of triple-glazed windows and the elimination of thermal bridging, hardly any energy is needed to heat or cool your home. The only semi-technical piece of equipment in a passive house is the heat recovery ventilator (HRV). With a home this efficient, smart thermostats and other cutting-edge technologies will have little to do.

Passive House makes a very durable building envelope. Its simple concept delivers significantly lower whole life cycle costs. These include design, construction, maintenance, to eventual demolition and landfill. Building to the Passivhaus standard now will lock in energy savings and a low carbon footprint for many decades.

Cooling and heating loads are reduced by up to 90%, ensuring an all-electric, truly sustainable net zero future. Passive house works in all climates, with successful projects ranging from the extreme cold of the arctic to the hot and humid tropics.

There are 5 basic principles in Passive House design:

    1. Continuous super-insulation
    2. Airtightness
    3. Thermal bridge elimination
    4. High-performance windows and doors, with solar shading
    5. Ventilation with efficient heat recovery

    As the world rushes to become carbon neutral, is Passive House still relevant?

    Building a Passive House home ensures that the transition to an all-electric, renewable energy future benefits everyone. Passive House supports the United Nations Framework Guidelines for Energy Efficiency Standards in Buildings and helps fulfill ten of the seventeen UN Sustainable Development Goals (SDGs).

    The Passive House high-performance building standard is recognized by the United Nations as the optimal way to build healthy, climate-resilient, affordable, and energy-efficient buildings. It sharply reduces greenhouse gas emissions and delivers resilient structures that can withstand extreme weather related to climate change. It has been argued by many architects and designers that Passive House should become the minimum standard for all construction.

    Can a Passive House also be Net Zero ready?

    Becoming “Net Zero Ready” is the Part 9 (residential homes) BC Energy Step Code target for 2032, keeping pace with other North American provinces and states that are rolling out their own incremental net zero readiness programs.

    Phius Zero is one path to a zero-carbon built home environment, and they certify the majority of all passive house projects in North America. Phius trains and certifies professionals and maintains the Phius climate-specific passive building standard. PHI certification demonstrates the team’s commitment to maintaining the integrity of the most widely recognized building energy-efficiency standard in the world.

    After three successful decades, the Passive House approach still reliably delivers very energy-efficient buildings. The small remaining energy demand can easily be met by adding renewable energy sources, making the home Net Zero/Zero Carbon. With the “Passive House + Renewables” approach, the initial focus is the building envelope, and then the balance of the energy requirement is addressed through renewable energy. Passive House and Net Zero were made for each other.

    Can an older home be retrofitted to Passive House?

    Yes, EnerPHit is the passive house retrofit standard and there are flexible pathways to upgrade systems and components in existing buildings. It is usually possible to reduce the energy consumption of a house to passive house or ‘damn near’ (un-certified) passive house levels. However, depending on the condition of the home, its shape, cladding and age, it may not always be cost-effective to complete the retrofit.

    Canadian houses are not typically built with great passive house potential. Many are not oriented toward the sun, or they experience considerable winter shading. Interior layouts and serious thermal bridges may pose design challenges. Often a significant portion of the home’s value has been invested into exterior brick or stone masonry, which would make exterior re-insulation non-viable.

    EnerPHit was developed by the Passive House Institute for existing buildings with structural limitations such as unavoidable thermal bridges. EnerPHit-certified buildings offer most of the benefits of a passive house building to the residents.

    The EnerPHit Standard can be achieved through one of two methods: based on the requirement for heating demand or the requirements for individual building components.
    Under the Energy Demand Method, the heating demand (calculated using the Passive House Planning Package PHPP) for EnerPHit buildings varies with climate, ranging from arctic temperatures to very hot. Under the Building Component Method, if all the individual building components on average meet the qualitative criteria, the project will still be eligible for EnerPHit certification.

    EnerPHit certification is only available for buildings for which modernization to the Passive House Standard for new builds would be impossible in practical terms, or uneconomical. EnerPHit certification offers all of the benefits of Passive House certification for retrofits, with the same improved comfort, quality assurance, durability and energy performance.

    The EnerPHit Retrofit Certification plan can deliver energy savings of between 75 – 90% in existing homes. The measures that contribute to certification include improved thermal insulation, a reduction of thermal bridges, significantly improved airtightness, installing triple-glazed windows, an upgrade to a heat recovery and ventilation system with an efficient heat generation solution, and the use of renewable energy sources.

    To begin the certification process you will need to engage a Certifier that has been approved by the Passive House Institute. If a thorough review by the Certifier shows that the building meets all criteria, then s/he may award one of the applicable seals: “Certified Passive House”, “EnerPHit Certified Retrofit” or “PHI Low Energy Building”.

    The PHI Low Energy Building Standard is suitable for buildings which do not fully comply with the Passive House or EnerPHit criteria.

    Does Passive House cost more?

    Passive House construction will typically cost 3 – 5% more than a traditional build. To manage your costs, engaging in the Passive House certification process from the very beginning of the project, and rigorously optimizing the design and construction every step of the way, are key. The Passive House training of designers, architects and contractors are important to support design and cost optimization, and quality control.

    Smart design can significantly reduce construction costs. That is how it’s possible to design a Passive House that can be constructed for almost the same cost as a code-built home of equivalent square footage.

    Passive houses require a simplified building shape for the thick exterior insulation, and a simple roof design to accommodate solar panels for achieving net zero. The savings from simplifying the design can typically be applied towards the cost increase for building envelope upgrades. Similarly, eliminating the traditional central heating system and installing point source heating systems represents a saving that can also be applied towards the passive house build.

    CleanBC Better Homes and Better Buildings renovation and new construction programs offer financial incentives, information and support to help households save energy and reduce greenhouse gas (GHG) emissions by making building-envelope improvements and switching to high-efficiency heating equipment.

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