Passivhaus Retrofit
Step-by-step for a whole house approach
The Trust's activities & what’s going on now?
Passivhaus retrofit - an introduction
The full Passvhaus retrofit masterclass lecture series is available to watch on demand - book now.
The retrofit challenge
Retrofitting existing buildings is undoubtedly a colossal challenge in transitioning the built environment to net zero. Even the majority of new homes built today are not nearly efficient enough, which means we will need to retrofit all 27 million homes, not just the older ones.
The sheer scale of this task is huge. It’s one home every 35 seconds between 2020 and 2050. Or, if every retrofit takes 4 people 6 months, it's 500,000 simultaneous retrofits needing 2 million people in the industry.
It’s also a complex undertaking. Every home is different which means some efficiency measures that work on one project may not be appropriate for another. Get it wrong and you could end up with damp and rot. Getting the right contractor with the right skills and experience is also a worry for most homeowners.
How can we make retrofit happen?
There are many issues surrounding retrofit at scale in the UK. The route to introducing higher standards and the associated costs are relatively clear for new-build properties. For retrofit, it is much more complex, and several interrelated issues must be addressed:
- How can we legislate to ensure homes are retrofitted?
- When should retrofit happen?
- How far/deep should retrofit go?
- How should it be financed?
- How can we ensure retrofits are done to a good standard?
- How do we make sure that a retrofit doesn’t result in damage to the building fabric?
We know how to safely retrofit buildings and we cannot afford to wait any longer. Read the Trust's recommendations on how to sensibly approach Passivhaus retrofit & assess whether it is right for your building here. If we had spent all the money raised by quantitative easing in 2007/8 on retrofit, then we would have done it by now…
There were many good ideas in the Bonfield Review and the arrival of PAS2035 as a compulsory retrofit requirement will result in better standards and hopefully a greater degree of trust from homeowners.
Where does Passivhaus fit?
The building physics principles behind Passivhaus apply to any building – but you may not be able to get quite the same results from an existing building where you aren’t really in control of the building’s orientation, structure, shape or amount of glazing. The Passivhaus standard, therefore, includes a retrofit standard called EnerPHit which takes these limitations into account and relaxes some criteria to reflect this. However, it is still a very demanding standard and will typically result in a building that outperforms a new-build property both in terms of energy and comfort. An introduction to the standard can be found on What is Passivhaus and there are some case studies below.
One step at a time
A radical whole house retrofit is likely to achieve the best results both in terms of energy reduction and comfort. However, this is a significant undertaking which could take place over several years. Getting the sequence right and decisions in the early phases are critical to ensure that the full potential of the retrofit is realised and that the project doesn’t inadvertently result in ‘carbon lock-in’. The EnerPHit process, therefore, includes tools to structure the retrofit in a step-by-step way, thus ensuring that the implications of each step are understood and properly planned out right at the start of the project.
The Trust's activities
The Passivhaus Trust’s activities relating to retrofit are intended to:
- Support work to examine the technical barriers to retrofit and how they can be overcome
- Support work to examine how retrofit at-scale can take place in the UK
- Support work to determine the level/depth of retrofit that is feasible and practical across the range of UK housing stock
- Lobby central government to introduce legislation to enable retrofit at scale
- Support the sharing of best practice knowledge and experience in deep retrofit
- Promote the building-physics principles of Passivhaus to support retrofit and, where appropriate, the EnerPHit standard
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The Passivhaus Trust's recommendations on assessing whether Passivhaus retrofit is right for you
What’s on now?
The Trust has published & collaborated on several research reports & guidance documents on Passivhaus retrofit. Looking for something more involved - take a look at the training offers we currently provide.
Guidance
Training
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2024 Managing Moisture: Joining the Passivhaus Retrofit Masterclass Series, hear from the authors of the research paper, Moisture & EnerPHit.
- 2024 Passivhaus Retrofit Delivery: An online training course delivered by PHT preferred training partner Coaction. Understand the delivery of deep fabric retrofits and what is needed to ensure projects are a success on site.
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2024 Enhanced Retrofit Fabric Improvement Training (ERFIT) Programme: This precursor course founded on the Passivhaus pillars, supports the need for growth in the retrofit supply chain. The ERFIT Programme aims to deliver trained practitioners with the technical knowledge and expert skills to install, advise and troubleshoot existing and new retrofit projects.
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2023 RIBA Passivhaus Retrofit Series: A series of 8 webinars, jointly organised by the Trust & RIBA, will offer an introduction to the benefits of Passivhaus retrofit and discuss how to communicate with clients. Delve into the retrofit processes and various toolkits, and discuss the differences between Passivhaus and Energiesprong retrofit.
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2021/22 Passivhaus Retrofit Masterclass lecture series: Expanding upon the retrofit guidance & PHT position paper, the Trust's Masterclass lecture series is available on-demand exploring EnerPHit approaches, and delivering retrofit strategies for common building typologies.
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2020/21 Demonstration of Energy Efficiency Potential (DEEP) retrofit study in conjunction with Leeds Beckett University. BEIS-sponsored research.
Retrofit case studies
As with the Passivhaus Standard, EnerPHit can be applied to many contexts. The handful of selected schemes below show a variety of building typologies from multi-home developments to one-off houses and even commercial schemes. For more examples in the UK please visit our Passivhaus projects gallery and map, or search for inspiration further afield in the International Passivhaus Buildings Database.
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.jpeg "Modernist EnerPHit Plus") |
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.jpg "Shepherds Barn EnerPHit, Image credit: Mark Siddall") |
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Project Sectors I Project Gallery I Project Map
Further Information
Previous PHT story: Estate-wide EnerPHit-informed retrofit planning - 1 August 2022
Previous PHT story: Renfrewshire retrofit programme aims for EnerPHit - 20 June 2022
Previous PHT story: Passivhaus Retrofit Masterclass series wrapped - 29 April 2022
Previous PHT story: Retrofit: The 'EnerPHit' in the room - 22 October 2021
Previous PHT presentation: Passivhaus Retrofit - 2019
Previous PHT story: Can EnerPHit at scale fight fuel poverty? - 27 November 2018
Previous PHT story: Bonfield Review: A step in the right direction? – 27 February 2017
EnerPHit & how it fits into the zero carbon agenda
Previous PHT story: Passivhaus on-demand training - 14 July 2022
SHRA Podcast: Energiesprong & Passivhaus - 09 November 2021
Homebuilding & Renovating: Why do we still not have a national retrofit strategy? - 17 November 2021
outPHit - Raising awareness for prefabricated and streamlined renovation concepts throughout Europe
outPHit: Analysis reveals energy savings potential of EnerPHit approach - 5 May 2023
Sustainable Renovation Guide - SEDA publication
