The Benefits of Passivhaus : A Sustainable and Energy-Efficient Solution

Residential and commercial builds in the UK are responsible for 25% of UK greenhouse gas emissions. In the UK, we have the oldest housing stock in Europe and potentially the world, primarily due to dwellings built during the industrial revolution. Significant changes need to be made to the pre-existing housing stock to reach the UK's target of zero carbon. 

Currently, most homeowners and developers in the UK build to the UK Building Regulations minimum standards and, in doing so, create sub-standard buildings. As part of the UK government's Industrial Strategy, the Construction Sector Deal and the Clean Growth Grand Challenge have set ambitious targets to halve energy use in new buildings by 2030. 

To achieve this, innovative energy and low-carbon technologies will be developed, along with quality-controlled construction methods. This is where the Passivhaus ‘International Gold Standard’ for building construction comes into play. It’s the best standard for construction in the world.

What is Passivhaus?

Passivhaus is a ‘whole house’ design approach developed in Germany during the 1990s by Professor Wolfgang Feist and Professor Bo Adamson. It’s an energy-efficient standard for buildings to reduce a building’s environmental and ecological footprint. A Passivhaus is a building that requires very little energy for heating or cooling. As a rule, a Passivhaus should use approximately 75% less energy than a standard UK new build.   

Key features of Passivhaus: 

• High-quality construction 

• Optimising passive solar 

• Increased insulation

• Rigid criteria for air tightness

• Compact and simple design 

• Thermal bridging is minimal  

• A mechanical ventilation system that recovers heat 

The first Passivhaus houses were built in 1991. Since then, over 50,000 homes, schools and offices have been constructed to the Passivhaus standard. Over that time, the buildings have undergone extensive monitoring to ensure Passivhaus buildings deliver what they promise. The Passivhaus design model specifies that the heating load of a building should be no more than 15kWh/m2/year. The collated data confirms this.

What are the main benefits of Passivhaus?  

The Passivhaus model has many benefits for the people living in these types of dwellings. One of the main benefits is how energy efficient they are. 

Energy efficient

Current Energy Performance Certificate (EPC) data shows that only 2% of new builds built in 2021 met top energy-efficient standards. This data shows a significant ‘performance gap’ with new builds. As the UK tightens its belt on the path to ‘zero carbon’ further CO2 reductions are likely to be put in place. Passivhaus is increasingly becoming the preferred, proven and cost-effective building method for effectively reducing energy consumption and CO2 emissions. 

Unlike solar-powered homes, passive houses use the sun's energy in the form of heat rather than solar panels, which convert sunlight into electricity. As a result of the design and construction of the home itself, passive houses eliminate the need for furnaces, fireplaces, and other conventional heat sources by capturing the sun's energy as heat.

Due to the 15kWh/m2/yr target, a Passivhaus home uses 90% less energy to heat than an average UK home and 75% less than an average new build. This not only saves the occupant money but also helps to reduce their carbon footprint. 

It’s no secret that energy is becoming more expensive. By adopting a whole-house approach to our new builds, or pre-existing buildings, we can reduce the demand for energy. Equally, when refurbishing a property reducing energy demand and using carbon-neutral heat sources should be our top properties.

Lower utility costs

Due to the nature of passive house design, traditional heating systems are unnecessary even in the most challenging climates, so bills for natural gas, propane, and heating oil could be eliminated. Pair that with super insulation and energy-efficient appliances, and the effect is reduced utility bills. 

For architects, Passivhaus goes beyond energy savings and environmental impact. It’s also about health, well-being and the quality of dwelling. 

Improved indoor air quality 

We spend approximately 90% of our time indoors. More time inside means more exposure to indoor air pollution, such as dirt, dust and gases, which harm our health. Inadequate indoor air quality has been linked to numerous lung diseases such as COPD, asthma and lung cancer.  

Healthy indoor air is achieved in two ways using the Passivhaus model: 

• by controlled home ventilation systems 

• by meeting thermal comfort criteria  

A building can either help or hinder our health. A whole-house ventilation system can reduce the risk of allergies and other health issues.

Healthy home environment 

Residents of Passivhaus homes benefit from improved indoor air quality, increased thermal comfort and self-regulated humidity levels. All of which create a more healthy and enjoyable home experience. Although health is not a key element of Passivhaus certification, it is in the designer's interest to achieve this.

Quality of build 

Due to the skill required to build a Passivhaus, highly skilled and quality-minded builders tend to gravitate towards the Passivhaus principles. The focus is very much on the quality of the build and creating a building of the future. 

Increased benefits for tenants 

For the rental sector, Passivhaus offers tenants a property they can be proud of and therefore are more inclined to help maintain. The energy costs are far lower, meaning that tenants living in Passivhaus properties are far less likely to go into rent arrears. 

Can you retrofit a building to Passivhaus standards?

You can retrofit an old property with the same principles as the Passivhaus standards. However, it is harder to meet the exacting standards of a Passivhaus new build, mainly due to the insulation levels needed. The Passivhaus Institute has a separate certification for appropriate retrofitting works.  The less stringent Passivhaus EnerPHit standard is often used for retrofitting existing properties.

Here at CMA we believe in the power of architecture to improve the lives of people and their environment, hence why we support the Architects Journal RetroFirst campaign and we’ve signed up to the RIBA Architect’s Declare movement.

If you are thinking of starting a project and feel that what we mentioned in this article might be relevant to you, contact us, we will be happy to help.