Rethinking “Eco” Insulation: Why We Need to Look Beyond the Marketing
By Ant
Sustainability is a word we hear daily in construction – and rightly so. But as someone at the coalface of building and retrofitting homes, I’m increasingly frustrated by how often the solutions we’re being sold fail to stand up to scrutiny.
Take insulation. Recently, I ran a viability assessment for a proposed system on a heritage property. The results were sobering:
269 years for financial payback
31 years for carbon payback
A product lifespan of just 25 years
These figures alone should stop us in our tracks. Yet the push to use it was relentless. Why?
The Hidden Costs of “Green” Materials
Many popular insulation systems like PIR boards (think Celotex and Kingspan) are marketed as eco-friendly, high-performance, long-lasting products. Yet independent research paints a more complex picture:
Up to 50% yield loss after 10 years due to thermal ageing and gas diffusion
Significant embodied carbon from production and installation that, when scaled, can rival concrete in environmental impact – though exact comparisons depend on material density and aeration
No third-party certifications or independent validation of performance claims in many cases
To illustrate, 1 m³ of polyurethane foam weighs around 600 kg, while 1 m³ of PIR board such as Celotex is closer to 80 kg. Even at lower mass, the embodied carbon remains significant.
And let’s not forget Grenfell – PIR insulation was listed among primary factors that accelerated the fire, underscoring the consequences of technical oversights.
The Part L Conundrum
The latest Part L Building Regulations aim to boost energy efficiency—an aim I support wholeheartedly. But the implementation risks pushing blanket adoption of high-carbon insulation without factoring in:
Realistic long-term U-value deterioration
Full life-cycle environmental accounting
Suitability in heritage and retrofit contexts
A one-size-fits-all regulatory approach rarely serves diverse building needs well.
Case in Point: Celonit
Celonit’s wood-wool insulation is a more natural alternative, certified to certain European standards and backed by eco-labels. However:
Their U-value claim (0.5 W/m²·K at 50 mm) isn’t yet supported by independent lab verification
Certifications don’t necessarily validate long-term thermal or carbon performance
Marketing may be strong—but verified, peer-reviewed data is currently lacking.
Where Do We Go From Here?
As an industry, we must:
Demand independent testing and certification, not just marketing claims
Use lifecycle analyses, weighing embodied carbon against operational performance carefully
Tailor insulation strategies to context—heritage, retrofit, new build, local climate, and energy sources
A truly sustainable approach demands more than ticking energy-efficiency boxes. It means critical thinking, full-life accounting, and diverse, proven solutions.
Final Thought
Our shared goal is a more sustainable built environment. But if the solutions we embrace are based on hype instead of rigorous data, we risk repeating our mistakes in the name of progress. It’s time for transparency, science, and context—not marketing spin.
1000 Trade Studios
