
Tap into the expertise of the AECB network by booking a personal consultation with one of our Expert Advisors
Our panel of Expert Advisors has been selected to represent the depth of knowledge and experience in the AECB network. We recommend them all as accomplished experts in sustainable building, each with their own unique achievements and qualifications. They offer strategic, commercial, design or technical insight and advice, whether you need an hour or a day of their time. Please contact them directly to discuss your requirements and receive a quote for consultation.
Each Expert Advisor runs one interactive AECB webinar each year on their area of expertise: these are available free to members.

Bill Butcher
Low energy, Radical retrofit Expert
Director Green Building Store
Bill Butcher
Director Green Building Store
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 and amongst other duties runs the construction and consultancy sections 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 on the Construction module of the CarbonLite CEPH Designer course and is a tutor on the CarbonLite Retrofit course.
Contact: bill.butcher@greenbuildingstore.co.uk ◦ @billbutch

Paul Jennings
Airtightness Expert
Director, Aldas
Paul jennings
Director of Aldas | Airtightness Expert | AECB Trustee
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.
Contact: paul.jennings@aecb.net ◦ 07866 948 200

Steven Fawkes
Energy efficiency & Finance Expert
Managing Partner, EnergyPro
Dr. Steven Fawkes
Managing Partner, EnergyPro Ltd BSc, DipTechEcon, PhD, FEI, FBIS
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 at www.onlyelevenpercent.com
Contact: steven.fawkes@energyproltd.com ◦ 077 0223 1995 ◦ @DrSteveFawkes

Tim Martel
PHPP & PHribbon Expert
AECB CarbonLite Author
Tim Martel
○ Retrofit Coordinator ○ CarbonLite Tutor ○ AECB Expert Advisor
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.
Contact: tim@phribbon.co.uk ◦ 01453 759466 ◦ 07531 288147
Sarah Price
Low energy retrofit Expert
Head of Building Physics & Consultancy, Qoda
Dr. Sarah Price
Head of Building Physics & Consultancy, Qoda
MSci, CEPH, AECB CLRetrofit, RICs Construction Project Management
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.

Eric Parks
Passivhaus & Low energy design Expert
Co-Director, Buckrose Ecological Architects
Eric Parks
Architect (BA Hons; B Arch; ARB registered) ○ Certified Passivhaus Designer ○ Co-Director of Buckrose Ecological Architects
Eric is an architect and long-term AECB member whose career has focused solely on practicing energy saving design. He has been a regular trainer on the AECB’s CarbonLite Passivhaus Designer course and is keen to asssit self-builders, other building practicioners and professionsals in desiging and building to high standards of energy saving and comfort.
Contact: eric@ericparks.co.uk ◦ 01653 696 198 ◦ 07746 159 711 ◦ @BuckroseEco

Robert Prewett
Deep low energy retrofit Expert
Director, Prewett Bizley Architects
Robert Prewett
Architect specialising in low energy fabric first design for new build and retrofit. Passivhaus certified designer.
Robert is an architect who has expertise in low energy design. Prewett Bizley has delivered new build passivhaus homes and have pioneered deep low energy retrofit projects across a range of house types. We were one of the first to talk about whole house design and continue to teach on the subject of retrofit.
Contact: rp@prewettbizley.com

Harry Paticas
Low-carbon deep-retrofit Expert
Managing Director and Founder of RAFT
Harry Paticas
BA BSc AAdipl CEPH RIBA – Architect and Managing Director and Founder of RAFT
Harry is an architect, passivhaus designer and recognised expert in the field of building retrofit. He has a 14-year track record as an architect and director of the successful architecture practice Arboreal Architecture. He recently featured in a one-hour blog post as a Climate Champion for the Architects Journal and has just completed the provision of technical advice for the passivhaus retrofit of special educational needs school for the DfE. Harry is an Expert Adviser for the UK Passivhaus Trust and the AECB (Association of Environment Conscious Builders), and a technical expert for the STBA (Sustainable Traditional Buildings Alliance). Harry is a frequent speaker, including at events organised by Historic England, Futurebuild, SPAB, Passivhaus Trust, ASBP, Historic Scotland, AECB, RIBA, and the London Diocese.
Awards In 2018 he was nominated RIBA London Project Architect of the Year and has won multiple awards for his projects including a RIBA National Award 2018, the CIBSE Building Performance Awards 2016, Don’t Move Improve Awards 2018 and multiple ASBP Awards in 2019 and 2021. His own home is an innovative retrofit and is the UK’s first step-by-step Passivhaus Enerphit retrofit project.
Contact: harry@retrofitaction.org.uk ◦ @harrypaticas

Peter Warm
Passivhaus training Expert
Director, WARM
Peter Warm
Director of WARM | MCIBSE | Passivhaus Certifier
Initial Chair of AECB (in distant past). Peter has over 30 years’ experience in energy consultancy, he claims he has carried out energy surveys on every type of building imaginable. Set up WARM: Low Energy Building Practice some 10 years ago with daughter Sally Godber, now 6 strong. He has built five of his own low energy buildings, including the WARM EnerPHit office (they do get better). Focusses on practical implementation of low energy buildings. Was first active Passivhaus certifier in the UK. Organised CarbonLite set of Passivhaus Trainers to promote low energy design, now a decade on. Dreams of Passivhaus becoming normal.Contact: office@peterwarm.co.uk ◦ 01752 542 546

Will South
Engineer & Designer Expert
Director of Etude
Will South
Director of Etude | MEng(Hons) | Passivhaus Certifier
Will is a Passivhaus Certifier, Passivhaus Designer and Mechanical Engineer focusing on building fabric and heat transfer. He can help you understand the energy performance of your design, prove compliance, learn the details of PHPP, or develop a construction design. Will has a particular interest in achieving energy performance in practice, with input on quality assurance during construction. He has previously helped manufacturers hone their design for thermal performance, and contractors meet Passivhaus airtightness requirements. Will is a Director of Etude, and teaches on the AECB Carbonlite Passivhaus Designer Course.
Contact: will.south@etude.co.uk ◦ 020 3176 4464

Mark Siddall
Passivhaus, Deep Retrofit and Building Performance Expert
Director, LEAP
Mark Siddall
Architect, Passivhaus Consultant and Building Performance Consultant
As an architect with over 20 years experience in the building industry, Mark works at the forefront of building design. If you need to develop better building technologies, improved techniques or new cost effective strategies that consider hygrothermal performance, comfort, health or well-being then Mark’s no-nonsense EROS framework will help you develop well considered, effective, scale-able solutions that avoid performance gaps. Mark has experience with retrofits, Passivhaus developments as well as housing, laboratories and listed buildings.
Contact: mark@leap4.it ◦ 0191 375 7702 ◦ 07795 031 700

Alan Pither
Energy consultation Expert
Director, Alan Pither Ltd
Alan Pither
Energy consultant and trainer; Director of Alan Pither Ltd.
Alan Pither is a highly experienced advisor who has worked on energy and environmental assessment throughout the UK for over 30 years, with a large proportion of his work involving the modelling of building energy efficiency both at the individual dwelling and housing stock levels. He has a thorough understanding of the Standard Assessment Procedure (SAP) and the BREDEM model that underpins it as well as reduced data and the minimum data sets used for assessing existing housing where the full details are not available. Since 1998, Alan has been working as an independent consultant and trainer, offering a wide range of services to building owners, local authorities, housing associations and commercial organisations. He is accredited as a Domestic Energy Assessor, an On Construction Domestic Energy Assessor and a CIBSE Low Carbon Consultant. He was also one of the first BREEAM assessors in 1990 and is a BREEAM Accredited Professional and licensed to carry out BREEAM assessments on most building types as well as Code for Sustainable Homes and Home Quality Mark assessments on new build homes. Alan has an outstanding reputation as a trainer of energy assessors and BREEM/Code for Sustainable homes assessors and is a Member of the Society for Education and Training. He has many years’ experience of training housing providers and local authority staff on energy advice and related issues including fuel poverty. He also delivers the Retrofit Coordinator training for the Retrofit Academy.
Contact: alan@alanpither.co.uk ◦ 07905 608414

Beth Williams
Structural Engineering & low energy construction Expert
Chartered Engineer, Build Collective
Beth Williams
Chartered Engineer, Build Collective | MEng (Hons), CEng MICE | Certified PassivHaus Designer
Beth is a Chartered Civil Engineer and Certified PassivHaus Designer, and associate at Build Collective, a bespoke engineering consultancy based in Bristol.
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.
Contact: beth@buildcollective.co.uk ◦ Twitter: @BethWilliamsSE

Diane Hubbard
Airtightness & Thermography Expert
Director, Greenfootsteps
Diane hubbard
Director, Greenfootsteps | Passivhaus Consultant | Certified PassivHaus Designer
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.
diane@greenfootstepscumbria.co.uk | https://greenfootsteps.co.uk/
01539 823119