Imran Jahn completes AECB CarbonLite Retrofit Foundation training

RISE Design Studio’s Design Director, Imran Jahn, has completed the AECB CarbonLite Retrofit Foundation course with a score of 94%.

The training strengthens our approach to improving existing homes: considering insulation, airtightness, ventilation, heating and moisture together, so that each design decision supports a warmer, healthier home with lower energy demand.

Imran Jahn’s AECB CarbonLite Retrofit Foundation training certificate, awarded on 10 October 2026. RISE Design Studio.

Why retrofit matters

The greenest building is usually the one that already exists. London's housing stock is old, much of it is draughty, and a large share of the UK's carbon emissions comes from heating these homes.

But retrofit is not simply a case of adding insulation. Every older home is a system of materials, moisture and air. Change one part and you affect the rest. Done well, retrofit brings:

• Comfort through even temperatures and no cold spots
• Health through clean, fresh air and no damp or mould
• Lower bills through a fabric that holds onto its heat
• Lower carbon by keeping the embodied energy already in the building

Done badly, it can trap moisture in walls and timbers, and store up problems for years to come. That is why specialist knowledge matters.

About the course

The AECB CarbonLite Retrofit Foundation course is run by the Association for Environment Conscious Building (AECB), one of the UK's most respected voices in low-energy building. It is delivered as part of the Warm Home Skills Programme.

The course was cited in the UK Government's Heat and Buildings Strategy 2021 as a route for the building sector to upskill towards decarbonising homes and heating. It is no light read: over 170 lessons across eight modules, tested through quizzes and scenario-based exercises.

The eight modules take a whole-house view of retrofit:

1. Introduction to CarbonLite Retrofit
2. Buildings in the UK Climate
3. UK Construction
4. Energy in Buildings
5. Moisture in Buildings
6. Case Studies
7. Building Services for Retrofit
8. Retrofit Investment Appraisals and Cost Modelling

Imran received his certificate on 10 October 2026.

The course is recognised by the Passive House Institute for CPD, and it is one of the entry routes to becoming an AECB CarbonLite Certifier.

What CarbonLite aims for

CarbonLite judges a home on four clear outcomes:

• Energy efficient: a well-insulated, airtight fabric with low heating demand
• Comfortable and healthy: steady temperatures, designed-out draughts, good ventilation and a low risk of overheating
• Low carbon: a move away from fossil-fuel heating, typically to a heat pump
• Quality assured: trained professionals and on-site checks, including airtightness testing

For retrofit, the targets are demanding but achievable. A certified home needs a space heating demand of no more than 50 kWh/m² a year and an airtightness of 2.0 m³/m².h or better, tested on site.

There are three routes: a New Build Standard, a Retrofit Standard, and a Step-by-Step approach for homes that are improved in stages over time. That last route matters for many of our clients, who often retrofit room by room or alongside an extension.

What it means for our clients

Our approach has always been fabric-first and Passivhaus-informed. We look at the building envelope before the boiler, and we design for the long term. Imran's training deepens that expertise at a senior level, right at the point where design decisions are made.

For homeowners, that means:

• A clear strategy from day one, so retrofit measures are planned as a whole rather than bolted on
• Fewer risks, with moisture, ventilation and detailing considered together
• Better value, by putting the budget where it makes the biggest difference
• Homes that perform, not just homes that look good on paper

Whether it is a full deep retrofit or a sensitive extension to a period home, our clients benefit from a team that understands how old buildings really behave.

Looking ahead

As signatories to UK Architects Declare, we believe architects have a real role to play in tackling the climate emergency. Retrofitting the homes we already have is one of the most powerful ways to do that.

Imran's achievement is part of a wider commitment across the studio to keep learning, keep testing and keep raising the bar.

Congratulations, Imran.

Thinking about retrofitting your home? We would love to hear about your project. Please do get in touch with the team at RISE Design Studio, we're happy to help.

→ Email us at architects@risedesignstudio.co.uk
→ Or call the studio on 020 3947 5886

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