The Cost of Passivhaus Construction and Retrofit in London
Kent House
An Architect’s Guide on the Economics of Building Green
As the world becomes increasingly aware of the need to reduce carbon emissions and combat climate change, the construction industry faces growing pressure to adopt sustainable building practices. This pressure is particularly acute in London, one of the most densely populated cities in the world. With millions of residents and countless businesses occupying its urban landscape, London is a city that demands innovative solutions to its energy needs. One such solution is Passivhaus construction.
What is Passivhaus?
Passivhaus is a building standard that originated in Germany in the 1990s. The concept behind Passivhaus is simple: build structures that are so well insulated and airtight that they require minimal heating and cooling. As a result, these buildings are remarkably energy efficient and provide exceptional comfort for inhabitants while promoting environmental sustainability. But what are the financial benefits of building or retrofitting to Passivhaus standards in London?
The Economic Advantages
One of the most apparent benefits of Passivhaus construction is energy savings. Because Passivhaus buildings are so well insulated and airtight, they require far less energy to heat and cool than traditional buildings. This translates to lower utility bills for residents and businesses, which can result in significant long-term cost savings. Passivhaus buildings use up to 90% less energy for heating and cooling than traditional buildings. Over the life of a building, this can result in significant financial savings for both the building owner and the occupants.
In addition to energy savings, Passivhaus buildings require less maintenance than traditional buildings. This is because the high-quality materials used in Passivhaus construction are designed to last longer and require less upkeep. For example, Passivhaus buildings often use triple-glazed windows, which are more durable and require less maintenance than single or double-glazed windows. The airtight building envelope of Passivhaus buildings also helps to reduce moisture damage and mould growth, which can lead to costly repairs.
Another financial benefit of Passivhaus construction is increased property value. As more people become aware of the benefits of sustainable building practices, demand for green buildings is likely to increase. Passivhaus buildings are highly valued because of their energy efficiency and comfortable living or working environment. This can result in higher property values for Passivhaus buildings, an important consideration for building owners and developers.
The construction industry is also recognising the value of Passivhaus construction. As more building owners and developers seek to reduce their carbon footprint and improve the sustainability of their projects, Passivhaus construction is becoming more mainstream. This means a growing demand for architects, engineers, and builders with experience in Passivhaus construction.
The challenges of Passivhaus construction
Of course, building or retrofitting to Passivhaus standards does come with some upfront costs. The high-quality materials used in Passivhaus construction can be more expensive than traditional building materials, and the design and construction process can be more time-consuming.
In addition to upfront costs, ongoing maintenance expenses also play a role in the economic disadvantage of Passivhaus. The need for regular monitoring and maintenance to ensure optimal performance can incur additional expenditures over time. Moreover, retrofitting existing buildings to meet Passivhaus standards can be even more expensive due to the challenges of incorporating energy-saving features into older structures.
However, many building owners and developers find that the long-term financial benefits of Passivhaus construction far outweigh the initial costs.
What Building A Passivhaus Costs
Building a Passivhaus in London entails significant upfront costs, although the long-term economic benefits are substantial. The initial expenses are primarily attributed to implementing energy-efficient features and high-performance materials. These may include advanced insulation, airtight windows and doors, mechanical ventilation systems with heat recovery, and solar panels for renewable energy generation. Additionally, rigorous planning and design processes tailored to Passivhaus standards incur additional expenses.
The expenses related to innovation in early Passivhaus projects are decreasing as the approach gains popularity. Studies indicate the additional costs of constructing a Passivhaus in the UK have decreased. As of 2018, it was found that implementing best practices in Passivhaus projects resulted in costs only around 8% higher compared to similar non-Passivhaus projects.
While these upfront costs may seem daunting, they are offset by remarkable long-term savings in energy bills.
At Ciarcelluti Mathers Architecture, we actively maintain a construction cost forecast for each project. Before we put pen to paper, our clients have the information needed to make informed decisions about a project's feasibility. During each design stage, we track the impact of any change to ensure the project continues to align with their expectations.
Want to discuss your project with us?
The Different Standards For Passivhaus
The Passivhaus standard has gained recognition worldwide as a benchmark for energy-efficient buildings. However, it is essential to note that there are different standards within the Passivhaus concept. These standards vary based on climate conditions, building types, and retrofit projects. Two main certification routes exist in the UK: the Passivhaus Classic and the EnerPHit standard. The Passivhaus Classic sets strict criteria for new builds, ensuring extremely low energy consumption and high comfort levels year-round.
The EnerPHit standard focuses on retrofitting existing buildings to achieve similar energy efficiency goals. Additionally, variations in regional climate conditions have led to different standards across Europe. For instance, colder climates like Scandinavia may have stricter insulation and heating system requirements than milder climates like Southern Europe.
Retrofit: An Alternative Approach To Passivhaus
While building a Passivhaus in London may come with substantial costs, retrofitting existing buildings to meet energy efficiency standards is gaining traction as a more economically viable option. Retrofitting refers to the process of upgrading and improving the energy performance of an existing building, rather than starting from scratch. By utilising this approach, the economic disadvantage associated with constructing a Passivhaus can be mitigated.
The standards for retrofitting to the EnerPHit standard differ from those of building new Passivhaus structures. As an alternative to the Passivhaus EnerPHit standard, the AECB has created a self-certified retrofit standard, with less stringent criteria more suitable for UK buildings. Provided the risks are managed by your designer, it is also possible to use the framework of the Passivhaus standard and lower targets to make the project economically feasible.
The focus is optimising insulation, reducing air leakage, and upgrading heating and ventilation systems. This approach allows for incremental improvements tailored to each building's characteristics and constraints, making it a more flexible and cost-effective solution. Moreover, retrofitting offers additional benefits, such as preserving historical architecture and reducing waste through repurposing existing structures.
Conclusion
In conclusion, building or retrofitting to Passivhaus standards in London can result in significant long-term financial benefits for building owners, occupants, and the wider community. Energy savings, reduced maintenance costs, increased property value, and a growing demand for Passivhaus expertise are just some of the financial advantages of this innovative building standard. As the world becomes more focused on sustainability and the need to combat climate change, Passivhaus construction will likely become an increasingly important part of the construction industry in London and beyond.
