A guide to the key principles of Passivhaus design
Passivhaus standards and sustainable design are currently at the forefront of every industry conversation, and rightly so. Companies are more concerned than ever about maintaining high levels of energy efficiency and reducing the impact of their buildings on the surrounding environment. In this guide our experts explore the principles of Passivhaus, the benefits of meeting these standards and previous examples of some of our Passivhaus certified buildings.
Learn more about our Passivhaus & zero carbon design services here.
Embracing Passivhaus design is a wise choice for those seeking a sustainable and energy-efficient living or working environment.
It offers unmatched energy efficiency, leading to significantly lower energy bills and a reduced carbon footprint. Passivhaus buildings also provide exceptional indoor comfort and air quality, ensuring a healthier and more comfortable living or working environment.
What is Passivhaus?
A Passivhaus, also known as a Passive House, is a highly energy-efficient building design and construction standard. It emphasises reducing a building's energy consumption to an extremely low level by incorporating key principles such as superinsulation, airtight construction, high-performance windows, and mechanical ventilation with heat recovery (MVHR).
Passivhaus buildings are designed to maintain a comfortable indoor temperature without relying heavily on traditional heating or cooling systems. They make effective use of passive solar heating and shading strategies while minimising thermal bridges that can cause heat loss. Energy-efficient appliances and lighting are typically used to further reduce energy demand.
Passivhaus design ensures a high level of indoor comfort, excellent indoor air quality, and low operating costs over the building's lifetime. Achieving Passivhaus certification requires rigorous planning and adherence to strict performance standards, making Passivhaus buildings a sustainable and eco-friendly choice for those seeking energy-efficient and comfortable living or working spaces.
Passivhaus is a strict set of criteria for low-energy buildings, which seeks to minimise the need for space heating and cooling. Originally developed in Germany in the 1990s using the principles of building physics, this cost-effective, low carbon design standard aims to reduce heating loss to a minimum through insulation and airtight systems. A passivhaus should maintain an almost constant internal temperature year round.
Fundamentally, Passivhaus buildings should not require a conventional heating system - instead, heating demands are met through pre-heating and heat recovery. A Passivhaus will still need a way to heat water, which is often done through solar heating or air source heat pumps.
Read more about Passivhaus requirements and the specific criteria through the Passive House Institute.
The 5 key principles of Passivhaus design
The Passivhaus design standard is guided by five key principles, which are often referred to as the ‘Five Pillars’ of Passivhaus design. These principles are fundamental to achieving high energy efficiency and comfort in buildings. Here are the five key principles:
1. Superinsulation
Superinsulation involves the use of exceptionally well-insulated building envelopes, including walls, roofs, and floors. Thick layers of insulation minimise heat transfer through these surfaces, reducing the need for space heating and cooling. High quality and continuous thermal insulation of the building envelope ensures separation between heated and cooled, inside and outdoor environments and reduces the risk of condensation. This is a fundamental principle of Passivhaus design, which minimises heat loss and improves thermal performance.
2. Airtightness
Airtight construction is crucial to prevent uncontrolled air leakage, which can lead to heat loss and drafts. Careful sealing of joints, gaps, and openings ensures that the building maintains a consistent indoor climate. Passivhaus buildings should have no more than 0.6 air changes per hour at 50 pascal. This is key to achieving energy efficiency and involves highly insulated walls, roofs, windows and floors.
3. High-performance windows and doors:
Passivhaus buildings feature high-performance windows and doors with triple-glazed windows and thermally efficient frames. These elements are designed to minimise heat loss while allowing natural light to enter. Windows play a big role in the heat performance of a house, as they are the weakest areas of the envelope.
4. Mechanical ventilation with heat recovery (MVHR):
Passivhaus buildings rely on mechanical ventilation systems with heat recovery (MVHR) to ensure a constant supply of fresh air while recovering heat from the outgoing stale air. This process helps maintain indoor air quality and reduces the need for additional heating. The heat from exhaust air is transferred to the fresh air through a heat exchanger, meaning no doors or windows need to be opened in order to achieve fresh air.
5. Thermal bridge-free construction:
Thermal bridges are areas in the building envelope where heat can easily escape or enter. Passivhaus design minimises thermal bridges through careful detailing and the use of continuous insulation. This principle ensures that heat transfer is effectively controlled throughout the building envelope. Thermal bridges can also increase the risk of condensation.
These five key principles work in synergy to create buildings that require minimal energy for heating and cooling, provide exceptional indoor comfort, and offer long-term sustainability. Passivhaus design standards are rigorous and require thorough planning, construction practices, and certification to ensure compliance with these principles.
What are the benefits of Passivhaus design?
The benefits of Passivhaus design span environmental, climate and financial areas and enable higher levels of building performance and improved wellbeing. Passivhaus construction ensures lower energy costs, a constant supply of fresh air which can be beneficial for health and wellbeing and a comfortable, quiet living space. These future-proofed building designs enable decarbonisation without the risks of rising fuel bills, guarantee good ventilation, reduce the health impacts associated with cold homes and the impact of external noise.
Our Passivhaus experience and previous projects
Client: University of Leicester
CPW’s MEP and Passivhaus designers were key members of the team responsible for delivering the University of Leicester’s pioneering new £42m facility, bringing its colleges of Medicine, Biological Sciences and Psychology under one roof. The Centre for Medicine, also known as the George Davies Centre is currently the UK’s largest non-domestic Passivhaus building, leading the standard for sustainable building design.
The design reduces total energy consumption from 500kWh/m²/yr in a typical building of this size to only 80kWh/m²/yr, cutting energy bills by 80% and achieving an EPC A-rating.
Client: Kings Hawford Junior School
Bartholomew Barn is a £1.3m multifunctional sports and drama building facilitating community events from games and assemblies to drama, music and dance for King’s Hawford Junior School.
The school needed a space that would be suitable for a wide range of activities, as well as provide a kitchen and servery for catering, changing facilities, showers and bathrooms to suit all users.
The building is the UK’s first ever building built and certified to Saint Gobain’s Multi-Comfort standard, and is also certified Passivhaus and EPC A rated.
Get in contact with our Passivhaus experts
Get in touch with our Passivhaus experts today and learn more about our Passivhaus & zero carbon services and previous projects. We take pride in developing low-energy buildings that stand the test of time and maximise user comfort and efficiency.