In this episode, we are joined by Attzaz Rashid (Barratt London) and Joel Callow (Beyond Carbon) to talk about Barratt London's move into Passive House.

It was a chance to get into what attracted Barratt to developing this Lo-E homes proposition and how they came to feel confident about committing to deliver certified Passive House apartments, the team effort that's been employed to make it work, and the way this change has brought about a renewed enthusiasm for the job in some of the project's participants.

It's a really interesting exploration of how the rigour and challenges of Passive House has affected Barratt's approach to high-density building, and how the Passive House approach has come to be recognised as advantageous to Barratt, in all sorts of ways. 

Finally, the critique of M&E design that's made late on in the episode is not a Barratt critique—as Az makes abundantly clear—this is one founded in Joel’s experience of inheriting issues that require Beyond Carbon’s expertise for their resolution.

Notes from the show

• Attzaz Rashid on LinkedIn
• Joel Callow on LinkedIn 
• The Barratt London website
• The Beyond Carbon website
• District heating and passive house - are they compatible? from the pages of Passive House Plus
• Barratt launches record passive house scheme also from the pages of Passive House Plus

**SOME SELF-PROMOTING CALLS TO ACTION**

We don't actually earn anything from this podcast, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Retrofit Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

Is there a collaboration problem in retrofit within the social housing sector? That was the premise for this conversation with Rafe Bertram, an architect and retrofit expert—appearing in a personal capacity—who was very surprised when I posed the question because he's found collaboration to be a strength in the sector, at least in London.

In the end it led to a conversation about what he's learned from the experiences he's had working on retrofits in the social housing sector, in his community, and even doing big flashy Apple stores.

The most interesting bit though is the strategy he's using to reduce the cost of retrofit, with his theory of reactive planning. It's an approach that takes a systematic integrated asset management approach and adds strategic opportunism into the mix in a way that enables him to piggyback essential works, like roof replacement, and use them as a catalyst for getting into a building to do the sustainability stuff that's usually a lower priority.

Notes from the show

• Rafe Bertram on Linkedin
• Retrofit Kentish Town 
• The Good Homes Alliance website
• Rafe's finance report for the Good Homes Alliance — “The Green Shift – The existing financial incentives for higher environmental performance of new homes” (October 2023) 

More links to articles about green building, favourable finance, and better valuations:

• Homebuyers pay a ‘green premium’ of up to £40,000 for the most energy efficient properties (September 2021)—Lloyds Banking Group
• Halifax includes EPC ratings in maximum lending calculations
• Halifax to use EPC rating in affordability calculations
• Octopus reducing interest rates for finance capital: 4 criteria = 1.25% discount, 6+ criteria = 2.00% discount

**SOME SELF-PROMOTING CALLS TO ACTION**

We don't actually earn anything from this podcast, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Retrofit Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

This episode is all about case study in circularity and a group of people turning waste into useful materials for the built environment. Daniel Dinizo and Charmaine Cu-Unjieng of NaturLoop are bringing a new bio-based product to market that transforms waste coconut husk into a material that's something between MDF and a particle board.

For us, this presented a chance to talk about how sustainable materials are developed, the challenges of bringing them to market and how responsible businesses can approach supply chain development (the big challenge now).

As professionals who work with LCAs, EPDs, and carbon calcs all the time it was refreshing to get into a product that will have an impact that can be accounted for in human terms, as well as the usual economic and environmental terms.

They're also fundraising right now, so here's the pitch from Charmaine.

NaturLoop at the Final Stage of Pre-Seed Funding
"NaturLoop, the Swiss–Philippine climate-tech startup behind Cocoboard, is at the final stage of its pre-seed round. Cocoboard is the first industry-ready fibreboard made entirely from coconut husk waste and natural adhesives—a truly biocircular material. Featured at Interzum Cologne 2025, Cocoboard embodies the shift in construction and furniture toward biocircularity—no longer a trend but the future of materials. Europe’s sustainable furniture market is set to more than double to $42.6 bn by 2032, with consumers paying around 10% more for sustainable products. NaturLoop is closing its round soon, inviting strategic investors to co-build a climate-positive business that reduces deforestation and uplifts poor coconut farmers—making the industry more future-proof."

Notes from the show

• Charmaine Cu-Unjieng on Linkedin
• Daniel Dinizo on Linkedin 
• NaturLoop on Linkedin 
• The NaturLoop website
• A short film about Cocoboard®
• An investor CTA from Charmaine
• An example of Cocoboard in use as a speaker box for a Schwab System

**SOME SELF-PROMOTING CALLS TO ACTION**

We don't actually earn anything from this podcast, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Retrofit Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

In this episode we are exploring the relationship between financial institutions and the built environment in relation to sustainability, building performance and mitigating climate change with Ian Bhullar and Ronnell Reffell from UK Finance, the UK financial sector's membership organisation.

The episode itself was prompted by a report that UK Finance published in relation to the incoming UK Government's own Warm Homes Plan: Greening Homes, Creating Growth: Unlocking demand for green home finance. Its recommendations will be familiar to anyone who has been working in the green building sector but it's notable because these arguments and demands are being presented by the banks and lenders.

For us this presented an opportunity to find out what the finance sector is actually thinking about how to address the demands of the built environment in relation to climate change and the financial risk that comes with it.

Most importantly, they're serious about the matter—this is not ESG-style fluff, they know they need to draw in expertise from built environment professional and they want to know what people like you think.

Notes from the show

• Ian Bhullar on Linkedin
• Ronnell Reffell on Linkedin 
• The UK Finance website 
• The report itself—Greening Homes, Creating Growth: Unlocking demand for green home finance

**SOME SELF-PROMOTING CALLS TO ACTION**

We don't actually earn anything from this podcast, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Retrofit Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

We're joined by our new friends from Building Atlas, Nick Taylor and Olga Khroustaleva, who join us for a conversation about commercial retrofit—the non-residential kind. 

They’ve got a data driven business Building Atlas that helps commercial asset owners to plan pragmatic retrofit pathways for commercial real estate.

This isn’t just important because of how much energy the non-residential sector consumes, it’s also because 70% of non-residential building assets are on course to become stranded assets because of their EPC rating and MEES regulation.

They are simplifying a complex problem into something that’s comprehensible—aggregating experience (and data) to give broad brush stroke direction that's useful. 

They’ve also published a paper about retrofit strategy for commercial buildings: The Beauty in Boring Buildings: The Business Case for Retrofit Beyond Flagship Assets.

Notes from the show

• Nick Taylor on LinkedIn 
• Olga Khroustaleva on LinkedIn 
• The Building Atlas website 
• Their recent paper — The Beauty in Boring Buildings: The Business Case for Retrofit Beyond Flagship Assets
• UK Government MEES guidance — Non-domestic private rented property: minimum energy efficiency standard - landlord guidance

  
  

**SOME SELF-PROMOTING CALLS TO ACTION**

We don't actually earn anything from this podcast, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Retrofit Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

In this episode Rose Chard joins us to describes her multilayered and multi textured approach to innovation and research.

It's a conversation about Energy Systems Captapult's experiment in prescribing heating to keep people warm—that's pretty much it, but there was a lot to talk about.

Notes from the show

• Rose Chard on LinkedIn
• The Inclusive Smart Solutions project that Rose mentions
• Warm Home Prescription® Insights and Impact Report (July 2024) by Energy Systems Catapult
• Warm Home Prescription recommended by 93% of health professionals in latest trial (September 2023) by Energy Systems Catapult
• One of the papers Jeff mentioned: Occupant Interactions and Effectiveness of Natural Ventilation Strategies in Contemporary New Housing in Scotland, UK
• The other one: Ventilation and Indoor Air Quality in Part F 2006 Homes (BD 2702) from 2010

**SOME SELF-PROMOTING CALLS TO ACTION**

We don't actually earn anything from this podcast, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Retrofit Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

In a slight departure from our usual building performance themes joining us for this episode we have Richard Muscat, a man who has experienced the world of investment and tech from a fascinating range of angles and is seeking ways to do things differently.

In essence, we’re looking at the way venture capital and climatetech are organised in ways that aren't conducive to delivering the impact that's promised. We're not just picking on VCs, we're using them as a means of highlighting a bunch of systemic economic issues—chief among them is how unrealistic goals for growth (in its myriad forms) almost always leads to failed impact. Perversely, it's a bug in the impact investment space that's a feature of the broader investment system.

We also get into concepts of degrowth and economic biodiversity.

Good Homes Alliance event
Launch event of our a best practice guide to ‘Water Efficiency and Reuse in Housing’ on Thursday 10 July.

Notes from the show

• Richard Muscat on Linkedin
• The Untangled website
• Richard's recent LinkedIn post that we mention
• The Project Drawdown website
• Human flourishing doesn't require perpetual growth; it requires sufficiency, by Jason Hickel
• Smarter Finance 4 EU — the project Jeff's been working on and promoting because green home certification is about not just energy use, or IAQ, etc, but how residents live their lives once they leave the front door i.e. nature + cycling + public transport + climate resilience etc. all matter

**SOME SELF-PROMOTING CALLS TO ACTION**
We don't actually earn anything from this, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Retrofit Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

In this episode we're talking about Zero Bills Homes, so we welcome back Nigel Banks, this time accompanied by his Octopus colleague Emma Fletcher*.

We're not directly talking Fabric Fifth again but the concept is central to the Octopus zero bills strategy i.e. prioritising decarbonising energy use and reducing the cost of energy use rather than focusing on reducing energy demand through fabric measures. As before, basic fabric standards are required in order to make the proposition financially viable.

As you might imagine, Jeff was keen to dig into the technical and performance side, so Nigel explains what’s going on in the standard and what they know about how well it’s functioning and Emma fills us in on how it's shaping up to evolve into a building standard in its own right. 

We're particularly keen because—although we might be sceptical, which we discuss—the action that Octopus is initiating will raise standards and will shape expectations that will influence the whole residential construction sector, and could go some way to catalysing the bridging of the skills gap.

*She, too, works at Octopus Energy—she is not an actual octopus.

Notes from the show

• Nigel Banks on Linkedin
• Emma Fletcher on Linkedin
• The Octopus Zero Bills proposition in their own words 
• The Octopus Tenant Power proposition
• Nigel Banks' addressing the embodied carbon question on LinkedIn 
• Link to The Octopus Energy Tech Summit (23rd June)
• The Fabric Fifth ZAP episode from last year

**SOME SELF-PROMOTING CALLS TO ACTION**
We don't actually earn anything from this, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Retrofit Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

This episode is all about a retrofit programme gone wrong in Preston and the effort required to fix it.

It's a story that was covered in the pages of Passive House Plus back in 2018 under the headline "Disastrous Preston retrofit scheme remains unresolved" and until recently we thought it remained unresolved.

We're joined by Filipe Amarante and Joanna Curtis to talk about the Preston Retrofit Catastrophe and all the work that National Energy Action has been doing to fix the grotesque damage that was wrought on a community in the 2010s. It's a project that's consumed at least four years and—in truth—will require many more to make good.

It's not a hopeless story though. The work NEA has carried out is full of lessons for anyone who works in retrofit to learn. They've taken a worst case scenario—one so bad it's hard to imagine how you could make it any worse—and developed a remediation programme that mitigates the worst of the situation while laying out a best-practice template for how one should approach place-based retrofit programmes.

They're also hosting a NEA webinar about the programme on 10 June: sign up here.

Notes from the show

• The Passive House Plus article: "Disastrous Preston retrofit scheme remains unresolved"
• Filipe on LinkedIn
• Joanna on LinkedIn
• The NEA website 
• The NEA's summary report on the project (and video): Warm and Safe Homes in Fishwick
• More photos of the disaster in "When retrofit goes wrong – lessons from Preston", a presentation by Kate de Selincourt, the writer who brought this story to Jeff's attention
• Cathy Come Home on IMDB
• A Taste of Honey on IMDB
• Riff-Raff on IMDB 

**SOME SELF-PROMOTING CALLS TO ACTION**
We don't actually earn anything from this, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Own Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**

We are joined by Valentina Marincioni (UCL, UKCMB) and returning guest Toby Cambray (Greengauge) to talk about the bane of all buildings: moisture.

Recently, they they’ve produced a simple explainer video about "breathability" in buildings for the UK Centre for Moisture in Buildings. Given Jeff's proclivity for referring to the 'sweatability' of buildings this seemed like a perfect opportunity to have Toby back and meet his colleague Valentina.

We got into the subject of moisture in some depth, discussed the key terms (vapour diffusion, hygroscopicity, and capillary action), why this all matters, what’s important to understand and how it’s easily misunderstood and easily miscommunicated.

We also play the audio from the video.

Notes from the show

• Buildings Don't Breathe, the video that led to the conversation
• Toby on LinkedIn
• Valentina on LinkedIn
• The UKCMB website and the tools and guidance they host there
• The recent Historic England paper: Air and Vapour Control Layers (AVCLs) in buildings of traditional construction. A literature review to understand appropriate use
• The BSI white paper about 4 Cs (context, coherence, capacity, and caution) framework for the development of moisture standards in the UK
• The paper Toby wrote with Sarah Price on moisture in Enerphit: Moisture and EnerPHit - Good Practice Guide (December 2023)
• Toby's appearance on the House Planning Help podcast talking about all things WUFI
• The Greengauge consultancy website (Toby's consultancy, with others, too)

**SOME SELF-PROMOTING CALLS TO ACTION**
We don't actually earn anything from this, and it's quite a lot of work, so we have to promote the day jobs.

• Follow us on the Zero Ambitions LinkedIn page (we still don't have a proper website)
• Jeff and Dan about Zero Ambitions Partners (the consultancy) for help with positioning and communications strategy, customer/user research and engagement strategy, carbon calculations and EPDs – we're up to all sorts
• Subscribe and advertise with Passive House Plus (UK edition here too)
• Check Lloyd Alter's Substack: Carbon Upfront
• Join ACAN
• Join the AECB 
• Join the IGBC
• Check out Her Own Space, the renovation and retrofit platform for women

**END OF SELF-PROMOTING CALLS TO ACTION**