Tap into the expertise of the AECB network by booking a personal consultation with one of our Expert Advisors

Low energy, Radical retrofit Expert
Director 21 Degrees

Bill Butcher has been the project leader of many low energy builds including the Denby Dale, Golcar and Kirkburton Passivhaus projects, the Stirley Farm EnerPhit project, and several notable radical retrofits. Originally trained as a quantity surveyor, he has over 45 years’ building experience both hands-on and managing , including construction of the Longwood low-energy house in the early 1990s. He jointly set up Green Building Store in 1995 which has subsequently rebranded to 21 Degrees in 2024. Amongst other duties, Bill deals with consultancy services of the business advising on numerous low energy and PH projects. Bill is a Certified Passive House Consultant and a Certified Passive House Tradesperson. A member of the AECB from inception, he also serves on the Technical Panel of the Passivhaus Trust, teaches Construction for the Coaction CEPH Designer and Trades courses, several architectural MSc courses. and other educational establishments. He also runs bespoke training days for contractors and self-builders.

Airtightness & Thermography Expert
Director, Greenfootsteps

With a mechanical engineering background, Diane’s interest in buildings arose a number of years ago with the realisation that our existing buildings are crucial to reducing our environmental impact.

Primarily interested in building physics, she completed an MSc at the Centre for Alternative Technology and over the past few years has had a number of papers published in the field of ventilation in traditional dwellings, together with undertaking project work for organisations such as the Society for the Protection of Ancient Buildings (SPAB) and Historic Environment Scotland.
In order to drive our understanding of older buildings forward, Diane continues her research into aspects of the energy consequences of ventilation in existing dwellings which will have particular relevance for rural, fuel-poor households.
Diane feels it is important this knowledge is applied and so continues to practice as an energy consultant to both householders and businesses.

Low energy retrofit Expert

Professional Institutions: AECB, PHT
Skills: Passivhaus and Low Energy Design, Project & Programme Management, THERM, SAP, WLCA, Teaching & Training
Sarah has experience of working on a wide variety of projects related to energy in the built environment from concept through to commissioning, and in 2011 she wrote the city wide energy strategy for Birmingham City Council. More recently she has specialised in project delivery, managing several Innovate UK projects and is now embarking on a BEIS funded project to develop a new external cladding system to achieve 80% reduction in carbon emissions in a single step. She is a specialist in the technical performance in buildings including thermal bridge analysis, energy modelling, moisture, MVHR and has a deep understanding of the relationship between different building performance standards in the UK from Building Regulations to Passivhaus.

Airtightness Expert
Director, Aldas

Paul Jennings of Aldas is the most experienced airtightness tester and consultant in the UK, with over 30 years’ experience. He has been an an AECB member for over 15 years and a Trustee for much of that time.  He is also a Director of the UK Cohousing Network.

He has presented at several AECB conferences and demonstrated the door fan test equipment at others. He has also given talks at Passivhaus conferences in Vancouver and Germany, as well as in the UK.  Paul has been involved in most UK PassivHaus projects in one or more capacities.

These schemes include:

• the first UK certified domestic and non-domestic PH projects in Machynlleth, both built by John Williamson, initially tested in 2008 and then retested after a decade of operation in 2018
• the Erneley Close (Manchester), Wilmcote House (Portsmouth) and Carlton Chapel House (North London) EnerPHit block refurbishment projects
• the Agar Grove area regeneration scheme in Camden, where neglected 60’s social housing will ultimately be replaced by over 500 newbuild PH units
• the Exeter Passivhaus swimming pool and leisure centre, currently under construction
• numerous individual newbuild custom- and self-build Passivhaus schemes

Paul is an experienced trainer and originated the “Airtightness Champion” concept, as well delivering numerous on-site trainings and many CPD seminars to architects and builders.  He developed the 12 Steps to Airtightness approach to enable UK contractors to reliably deliver airtightness in Passivhaus and other low-energy projects. Aldas offers planning and consultancy and online and practical airtightness training.

Structural Engineering & low energy construction Expert
Chartered Engineer

Beth is a Chartered Civil Engineer and Certified PassivHaus Designer, and associate at Momentum Consulting Engineers in Bath.
Beth has over 10 years’ experience in low-energy and low-carbon design and construction, focussing on timber frame PassivHaus buildings. Her project experience ranges from domestic extensions to new build sports halls and high security NHS facilities.
Alongside practice work, Beth is a visiting tutor at Bath, Cardiff and UWE architecture schools, and group leader for the AECB Bristol & Bath local group. Beth is passionate about making low-energy buildings simple to build, affordable and available to all.

PHPP & PHribbon Expert
AECB CarbonLite Author

Tim is an expert in PHPP energy calculations for new build and retrofit projects, Embodied CO² calculations, PAS2035 calculations, software and moisture issues. He’s the author of the AECB PHribbon software, used with PHPP, and a standalone Embodied CO² calculator. This is backed up with considerable expertise in Excel, macro/Visual Basic programming and calculations. He has been a Retrofit Coordinator since 2017 and also has experience in THERM for Thermal Bridge calculations and handling Omnisense monitoring data.

Energy efficiency & Finance Expert
Managing Partner, EnergyPro

Dr. Steve Fawkes has over 30 years experience in energy efficiency including delivering large energy management programmes, co-founding three energy service companies, implementing innovative energy services transactions, and advising governments. He founded EnergyPro, which provides advice, asset management and investment to accelerate the energy transition. EPAL, EnergyPro’s JV with EESL has invested more than £60m in energy efficiency since March 2017. He has received awards from the Energy Institute, the American Council for an Energy Efficient Economy and the Indian Business Group. He presents globally and has written more than 350 publications on energy efficiency including three books and a regular blog: www.onlyelevenpercent.com.

Architect, Passivhaus Consultant, AECB Certifier and Building Performance Consultant

As an architect with over 32 years experience in the building industry, Mark works at the forefront of building design.

Whether it is new build or a retrofit, as an experienced Architect, Passivhaus Consultant and  AECB Certifier, Mark can help you assemble a design team, find and support suitable contractors, solve design problems and develop a detailed technical solutions so that your high performance building avoids pitfalls and is optimised to achieve your goals.