By Maria Miranda on Mon 02 December 2024 in Insights
Is Passivhaus achievable in the UK
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Energy efficiency and sustainable living have become key priorities in addressing the UK's housing challenges. It is estimated that the housing stock in England alone accounted for 100 million tonnes of CO2 emissions in 2022*. In an effort to reduce energy consumption, Passivhaus, also known as or Passive House, has emerged as an innovative solution in sustainable architecture and construction.
In light of government targets to build 1.5 million new homes in the next five years, and Scotland's decision to implement a Passivhaus-equivalent standard for new builds from 2025, the housing sector faces critical choices about future development. Can Passivhaus standards effectively address the UK's housing efficiency, affordability, and sustainability challenges?
This report will examine the elements of the Passivhaus standard, analysing the barriers preventing its widespread adoption across the UK's housing stock. By exploring the challenges and opportunities this approach presents, we aim to understand why Passivhaus, despite its significant potential, has not yet become a mainstream construction standard.
The report covers:
- The current state of UK housing
- Passivhaus myths and FAQs
- The barriers to Passivhaus: is Passivhaus achievable across the UK?
- 1.5 million new homes — how many will be Passivhaus?
- The cost versus reward of Passivhaus
- Passivhaus principles versus Passivhaus standards
Key Findings
- Only 14% of UK councils have delivered Passivhaus projects, as of 2024
- 34% of London Boroughs have delivered Passivhaus projects
- The number of homes in England with an ‘A’ or ‘B’ EPC Energy rating has only risen by 2% in the past five years, compared to 3% in Scotland
- Building to Passivhaus standards would be expected to add between £5,320 and £10,640 to the construction cost of an average-sized three-bedroom semi-detached house
- In 2022, the average modelled energy cost in England was £1,434/year - an average passive house would expect to pay around £800 less than this
The current state of UK housing
Understanding the need for energy-efficient housing standards requires a close look at the UK's current housing landscape. The insights in this section come from Airflow’s analysis of the English Housing Survey and the Scottish House Condition Survey.
Homes in England and Wales
The energy efficiency of UK housing is improving, however, there are significant steps to be taken. As of 2022-2023, over half of England's housing has an Energy Performance Certificate (EPC) rating of D or less, indicating the homes are less than 68% energy efficient. Only around 3% are rated A or B, i.e. very energy efficient.
This represents a rise of only 0.3% compared to the previous year, and just 2% in the last five years. While moderately-efficient C-rated homes have increased by almost 16% in five years, this progress is still far from optimal energy efficiency.
Newer buildings tend to be more energy efficient, due to improvements in airtight construction, 83% of houses built after 1990 rated A, B or C. However, 17% of these newer homes are still low efficiency, leaving thousands of residents with higher energy demands. One human impact of these figures is that a third of people in the UK find it difficult to pay their energy bills. In fact, 12% of people in England report being unable to keep comfortably warm in their living rooms during cold weather.
The financial impact is significant: owner-occupied and private rented dwellings have the highest energy costs, averaging £1,599 and £1,270 per year respectively, compared to £991 for local authority and £975 for housing association homes.
Data suggests that improving energy efficiency in the home is a priority for many, as nearly three-quarters of owner occupiers carried out improvement works on their homes in the last 5 years, with energy efficiency being the motivation for 33% of these projects.
EPC ratings are important because they indicate the cost of heating and lighting, as well as potential CO2 emissions. At a time when high energy prices are set to be the “new normal,” reducing costs where possible is essential.
Homes in Scotland
With 52% of homes rated as EPC band C or better under SAP 2012 in 2022, Scottish dwellings have proven slightly more energy efficient than those in England and Wales. At the top end, around 6% of homes in Scotland are rated EPC A or B, compared to only 3% in England.
The impact on social housing
ONS data shows that social rented homes in England and Wales are more energy efficient than their private rented and owner-occupied counterparts, with an average EPC rating of C. Housing in the Scottish social sector similarly outperforms other sectors. However, tenants continue to face financial strain.
Despite higher energy efficiency ratings, social housing tenants are disproportionately affected by rising energy costs. Social renters in the most inefficient homes spend up to 15.5% of their income on heating — equivalent to nearly two months' worth of their annual income. Social renters are also the group that are most likely to fall behind on their fuel bills — around one in eight social renters.
The benefits of improving energy efficiency in social housing make this a priority, with potential advantages across all housing sectors. Passivhaus offers a promising solution, but implementation challenges and industry misconceptions currently limit its broader adoption.
Passivhaus myths and FAQs: what you need to know
Since its inception in Germany in the late 1980s, Passivhaus has been adopted across Europe, but certain persistent misunderstandings may have hindered its wider acceptance.
To provide clarity, Alan Siggins, Managing Director of Passivhaus Trust member Airflow, has responded to some of the most frequently raised questions and myths about Passivhaus.
FAQs
Is Passivehaus net-zero?
“Passivhaus buildings are optimised for net-zero, however, they are not inherently net-zero. The definition for net-zero construction is not standardised, unlike Passivhaus, so there are a couple of different definitions. For some, a net-zero structure is one that generates as much energy as it consumes. Passive houses are designed to reduce energy use, not generate energy. Achieving net-zero is not easy, but reducing energy demand to Passivhaus levels gives us the best chance of achieving it.”
Is Passivehaus worth it?
“This question is much more subjective. Passivhaus is generally considered worth the investment, especially in the long-term. Houses designed to Passivhaus standard can offer energy savings of up to 90% and the indoor air quality is improved, so you’ll see a significant reduction in running costs and improved comfort and health benefits. There’s also the environmental side of things. Passivhaus buildings have a much lower environmental impact, allowing for more sustainable living and contributing to reducing climate change. However, Passivhaus buildings tend to have higher upfront construction costs compared to traditional buildings. Whether Passivhaus certification is worth it will depend on your current situation and needs.”
Can you have a Passivhaus without MVHR?
“No, an MVHR system is an essential part of a Passivhaus so without it, you wouldn’t meet the Passivhaus standard. MVHR allows Passivhaus buildings to maintain high indoor air quality while recovering and recycling heat that would otherwise be lost. Without it, a building would not be able to achieve the necessary balance of airtightness and ventilation required by the Passivhaus standard.”
Is Passivhaus equivalent good enough?
“There are other building standards that share some similarities with Passivhaus, like the EnerPHit retrofit standard. Scotland is also defining the Scottish equivalent to the Passivhaus standard for all new build houses in Scotland. The equivalents are generally considered to be less demanding than Passivhaus in terms of the criteria buildings need to meet. Passivhaus is seen as the ‘gold standard’ for energy-efficient building design and is a reliable way of making sure a building is able to achieve the highest energy savings, comfort, and environmental impact. That said, building to an equivalent standard without Passivhaus certification is still a good option for prioritising energy efficiency and ventilation in a house. Just be aware that Passivhaus alternatives may not be as rigorous as the official standard.”
Myths
Passivhaus is more expensive than a traditional new-build.
“It’s true that Passivhaus buildings typically have higher upfront construction costs than traditional new builds, however this difference can vary and the cost of projects has reduced over the years. Passivhaus Trust, which certifies passive house buildings in the UK, suggests that best practice costs were around 8% higher than similar non-Passivhaus projects in 2018. As Passivhaus design becomes more mainstream, we expect the cost to continue decreasing, as the industry gains more experience and the necessary materials and technologies become more widely available.”
All elements of the building must be Passive House Certified products.
“No, not all components of a Passivhaus building need to be certified Passivhaus products. Only the MVHR unit needs to be Passive House Certified. Passivhaus focuses on the overall performance of the building, rather than requiring the use of specific certified products.”
You can't retrofit Passivhaus.
“Yes, it is possible to retrofit existing buildings to meet the Passivhaus standard, but it is challenging. Since passive house principles are harder to achieve in existing properties, the Passivhaus Trust developed the EnerPHit standard. The criteria for EnerPHit are more relaxed than those for Passivhaus, but meeting this standard still means that the building will likely outperform new builds for comfort and energy use.”
Passivhaus is just about airtightness.
“No, Passivhaus is not just about airtightness, although it is a key component. The Passivhaus standard encompasses a holistic approach to building design, incorporating strategies such as high-performance insulation, optimised window and door placement and MVHR. Air tightness is a part of this approach, as it allows the building to maintain indoor temperatures and air quality while minimising energy loss. However, there’s much more to it than that.”
The barriers to Passivhaus: is Passivhaus achievable across the UK?
Passivhaus offers comfortable and energy-efficient building design, but achieving full Passivhaus certification comes with strict requirements that pose challenges.
When examining the requirements of Passivhaus, the barriers become apparent:
Airtightness
Passivhaus requires a maximum of 0.6 air changes per hour at 50 Pascals of pressure, to reduce heat loss and protect the building. Maintaining this high level of airtightness is extremely difficult, especially in retrofit projects where the existing structure may have many air leaks. The air sealing techniques and quality control measures add complexity and cost to the construction process.
Thermal comfort
There are strict limits on overheating. Indoor temperatures cannot exceed 25°C for more than 10% of the hours in a year. This tight control on thermal comfort can be challenging to achieve, especially in regions with hot summer climates. Maintaining this level of temperature regulation requires careful design of the building.
Space heating demand
Passivhaus has an ultra-low annual space heating demand target of 15 kWh/m² or 10W/m2 at peak demand, which can require complex and expensive construction materials and methods. This prices some projects out of meeting the Passivhaus standard. However, it’s thanks to this demand that Passivhaus energy use can be so low, about 10% of the energy used in conventional buildings.
Space cooling demand
Similarly to heating demands, the Passivhaus requirement to limit yearly space cooling demand to no more than 15 kWh/m² calls for specialised passive and active cooling strategies.
Primary energy demand
Passivhaus has limits on the building's annual energy demand for heating, cooling, household electricity and primary energy use. Meeting these targets requires investment in high quality insulation, windows, and other specialised components. The upfront costs associated with Passivhaus construction can be a deterrent, especially for smaller-scale projects or those with tight budgets.
Passivhaus projects must also have a Passivhaus certified MVHR system. Most of these requirements bring about an additional level of expertise or cost.
Beyond the demands of meeting Passivhaus standards, there are limitations in existing skills and experience within the construction industry that could also hinder wider Passivhaus adoption.
While full Passivhaus certification isn’t always achievable, its principles, such as improved insulation, airtightness, and ventilation, can still be widely applied. These approaches, while they may not meet exact Passivhaus performance thresholds, can still deliver substantial energy savings and enhanced occupant comfort and health. The Scottish Government has already committed to its own equivalent to the Passivhaus standard for all new build homes. This type of building is constructed around the needs of the end user, and offers benefits throughout its lifetime.
These improvements can be especially important in situations like social housing, where energy poverty is a significant concern.
1.5 million new homes — how many will be Passivhaus?
The UK government has set ambitious targets for new home construction over the next five years, with plans to build 1.5 million homes. The introduction of this many new homes presents an opportunity to significantly improve the energy efficiency of the UK’s housing supply and shield households from high heating costs. However, despite the benefits of Passivhaus, it's unlikely that a large proportion of these new homes will meet the standard.
Construction costs continue to be a primary deterrent, with developers and local authorities perceiving Passivhaus as more expensive, despite evidence of only an 8% premium compared to standard construction. This perceived cost barrier, combined with limited understanding of long-term savings, means most new developments choose to prioritise immediate savings on construction expenses over future energy efficiency.
However, there is hope that the Future Homes Standard will be brought in to mandate much higher energy efficiency standards for new residential construction projects. A spokesperson for the ministry for housing, communities and local government has said: “We want to ensure new homes and buildings are sustainable and fit for the future.” Building today’s homes to a higher standard will avoid the need for retrofitting, at a higher cost, in the future.
Social rented housing needs
While these new homes will be primarily funded and delivered by the private sector, the demand for social rented housing remains high. The National Housing Federation has highlighted a need for 90,000 new social rented homes every year to meet housing needs in England. However, an average of only around 7,000 new social rented homes have been completed in the past five years.**
Housing associations and local councils play a crucial role in addressing this housing shortage, delivering many of the UK’s new homes. Their work to meet Passivhaus offers a glimpse of the potential transformation in social housing.
As of May 2023, a limited number of local authorities and housing associations have delivered Passivhaus homes in the UK. Of the UK’s 317 principal councils, 43 of them have delivered Passivhaus homes in the UK, as have a further 41 housing associations. The fact that 84 organisations have successfully delivered Passivhaus homes, despite the aforementioned challenges, demonstrates that it is achievable within the UK context. The picture across London is more promising, with 11 of the 32 boroughs (34%) having completed Passivhaus projects.
Why have only 14% of councils delivered Passivhaus?
The lack of interest in Passivhaus among councils and housing associations is due to factors such as higher upfront costs, lack of expertise in Passivhaus design and construction, and concerns about the complexity of meeting Passivhaus standards. The absence of policy incentives to pursue such a high standard of energy efficiency and design also leaves many councils opting for traditional builds. This choice may save organisations 8% of the cost to begin with, but leaves tenants bearing higher ongoing energy costs.
The case for Passivhaus in social housing is compelling, particularly given the current challenges of energy poverty, poor housing conditions, and rising utility costs.
The cost versus reward of Passivhaus
Passivhaus construction is conceived as expensive, but long-term energy and maintenance savings narrow the initial cost gap.
There are two main cost areas: upfront investment and ongoing operational costs. Upfront investment includes all expenses for the construction and achieving Passivhaus certification, if required. Ongoing operational costs includes any ongoing expenses to maintain and live in the home, including bills and repairs.
The upfront investment for a passive house is higher than for a traditional build, by around 8%. Passivhaus Trust also indicates that by ‘removing the costs associated with quality assurance and considering further development of skills, expertise and supply chain maturity… extra costs could come down to around 4% or less.’ The construction of a standard three-bedroom semi-detached house costs approximately £133,000, according to The Housing Forum. Meeting Passivhaus standards would add between £5,320 and £10,640 to this project.
The Housing Forum also estimates that a typical two-bedroom high-rise flat would be £225,000, meaning the additional cost of implementing Passivhaus standards would be between £9,000 and £18,000.
After the initial build, though, operational costs for passive houses are significantly lower, which may eventually offset the upfront cost for the owner or renter.
In England in 2022, the average energy use for homes was 231 kWh/m²/year, costing £1,434 annually. For less energy efficient homes, average annual energy costs were even higher — around £1,561 for D-rated to £2,662 for G-rated dwellings. By comparison, a passive house cannot exceed an energy use of 60 kWh/m²/year — just over a quarter of a typical home’s consumption. Based on average daily standing charges in the last six months of 2024, a typical standing charge for the year is around £336. Taking this into account, an average passive house (of the same size) would expect to pay around £621 in annual energy bills. This makes for an estimated annual saving of over £800.
Even when the passive house is meeting maximum energy use, the initial cost saving could be reclaimed in as little as seven years.
There are also non-financial benefits for occupants of passive houses, such as improved comfort and health benefits, which can’t be ignored.
Passivhaus principles versus Passivhaus standards
Whilst Passivhaus has garnered the reputation of being the gold standard, not every energy-efficient home needs to be Passivhaus certified. In case of budget constraints, a non-Passivhaus alternative may be a suitable option for comfortable and sustainable living. Therefore, it’s important to understand the connection between Passivhaus principles, the general energy-efficient design approach, and Passivhaus standards, the strict certification criteria.
The five core Passivhaus principles are:
- Thermal bridge free design
- Superior windows
- Ventilation with heat recovery
- Quality insulation
- Airtight construction
These can be achieved in many housing or building projects, without the added performance-based stipulations of Passivhaus. For example, aiming to achieve high levels of airtightness would reduce heating needs and allow ventilation systems to work effectively, even if levels don’t quite meet Passivhaus’ requirement of less than 0.6 air changes per hour at 50 Pascals. This can help reduce project costs, but still result in similar end-user benefits.
Conclusion
Widespread adoption of Passivhaus in the UK is achievable, although success depends on addressing key strategic challenges. By systematically addressing skills gaps, regulatory barriers, and public perception, the UK can transform Passivhaus from a niche standard to a mainstream housing solution.
In the meantime, it is also possible for construction projects and government policies more broadly to embrace Passivhaus principles, which bring many of the benefits, without the same stringent and costly requirements of full Passivhaus certification.
The potential for significant energy efficiency and long-term sustainability makes this transition not just desirable, but essential.
For more general information on Passivhaus, you can read our Passivhaus Guide.
Data gathered in October 2024
*English Housing Survey 2022 to 2023 (energy report):
**Live tables on affordable housing supply:
https://www.gov.uk/government/statistical-data-sets/live-tables-on-affordable-housing-supply