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Passive house, aka passive solar house aka Passivhaus in German, is a type of sustainable building design and voluntary construction standard that aims to create highly efficient and comfortable living spaces.
This interesting concept came about in Germany in the late 1980s. Today, with more and more people gravitating toward reducing their ecological footprint, the idea has gained popularity worldwide.
It’s interesting to note that there are similar energy-efficient building standards, such as LEED (Leadership in Energy and Environmental Design), the Zero Energy Ready Home in the United States, and the Net Zero Energy Building (NZEB) that exist.
The concept of “Passive House” can apply to any type of building – an apartment building, a condo, a single-family home, a commercial building, an office space, or a historical renovation.
The primary goal is to minimize energy consumption for heating and cooling while maintaining indoor comfort. This is achieved through a combination of design principles, insulation techniques, and efficient use of renewable energy sources.
What are the identifying features of a passive house?
A passive house aims to create a stable and comfortable indoor environment throughout the year, with minimal reliance on conventional heating and cooling systems. You can identify certain characteristics.
- Super insulation: Such buildings are constructed with highly insulated building envelopes to minimize heat loss or heat gain through the walls, roof, and flooring. This insulation, along with insulated windows and doors, helps create a well-insulated and airtight building that has less heat loss in the winter and heat gain in the summer.
- Airtightness through thermal bridge-free design: Airtightness involves the use of high-quality building materials and construction techniques. It ensures that the building envelope is free from unwanted air leaks. Thermal bridges are areas of a building where heat can easily transfer between the interior and exterior, leading to energy loss. Passive houses aim to minimize this thermal bridging through insulation materials and techniques, such as insulated frames around doors and windows and continuous, uniform home insulation.
- High-performing windows and doors: Passive house design emphasizes the use of high-performance doors and windows. These are typically triple-glazed, with low-emissivity coatings and insulated frames to reduce heat transfer. Moreover, they are strategically placed to maximize natural light and solar gain (passive solar design) while minimizing heat loss. Moreover, there’s sufficient use of shading devices.
- Mechanical ventilation with heat recovery: Passive houses employ mechanical ventilation systems with heat recovery (MVHR) to maintain a continuous supply of fresh air. The MVHR system extracts stale air from the building and simultaneously supplies fresh, filtered air. It reduces the need for additional heating. And hence lowers your energy bills significantly.
- Usage of energy-efficient appliances and light fixtures: Energy-efficient appliances, LED lighting, and other energy-saving measures minimize electricity consumption. A passive house can significantly reduce energy consumption by up to 90% compared to conventional buildings. And, reduces environmental impact to a large extent.
What are the specific requirements of a passive house?
A building must be in compliance with the passive house standards to qualify as energy-efficient.
Space Heating Demand Less than 15kWh in a year or less than 10W per square meter of usable living space Space Cooling Demand Less than 15kWh in a year or less than 10W per square meter of usable living space. And, some climate-dependent allowance for dehumidification Primary Energy Demand Less than 120kWh for heating, cooling, hot water, and domestic electricity in a year. Airtightness Less than 0.6 air changes (at 50 Pascals pressure) per hour Thermal Comfort Not more than 10% of hours (over 25°C) in a year
What is the difference between a passive house and LEED?
A Passive House and LEED are both building standards that focus on energy efficiency and sustainability. However, they have different approaches and areas of emphasis. The passive house concept focuses on achieving ultra-energy efficiency through design strategies, while LEED takes a broader approach, considering multiple sustainability aspects across different building types and locations.
For passive house certification, a building must comply with specific performance criteria related to energy consumption and air leakage. The standards for a certified passive house are performance-based and adaptable to different climate zones.
LEED certification, on the other hand, is a point-based rating system that evaluates a building’s sustainability across various categories such as the building’s performance, energy savings, design strategies, water efficiency, and sustainable materials.
What are the advantages and disadvantages of a passive house?
- More living comfort regardless of the weather. Such a design helps to eliminate cold spots and minimize heat loss.
- Quality and efficiency due to superior insulation and airtight design aka thermal bridge-free design.
- The airtight design may help prevent moisture-related damage.
- Sustainability and eco-friendly concept that helps people consume less energy and preserve energy resources for future generations. Such a building uses one-tenth of the energy consumed by average houses. That’s why a passive house is also known as a “factor 10 house”.
- Environmental protection through sustainable construction and home renovation.
- Cost-effective in the long run as there’s a lesser requirement for expensive heating and cooling systems. And, the high upfront costs are offset by long-term energy savings.
- Versatile design that can be utilized by skilled architects and passive house designers worldwide.
- Comes with higher upfront costs as building a passive house often requires specialized design, materials, and construction techniques.
- The design and construction of passive house projects are more complex than ordinary buildings. A passive house design requires precise execution to achieve optimum energy performance.
- There is a limit on design flexibility and architectural options due to the strict passive house-building standard. For example, there are constraints on window size, orientation, and overall building shape as well as design.
- There may be potential overheating in case of excessive solar exposure or inadequate shading.
- It might affect moisture management, such as moisture buildup and condensation, due to extreme airtightness. This could lead to potential mold growth, reduced indoor air quality, and building deterioration.
- Requires regular maintenance and operation. Such buildings require a specific type of home maintenance with specialized tools and equipment to ensure optimal energy performance.
Passive house buildings can achieve remarkable energy efficiency and provide comfortable indoor environments. With careful planning, attention to detail, and appropriate expertise, you can maximize the benefits of passive house construction.
A sustainable building design offers economical, high-quality structures and cozy, healthful living spaces.