Our philosophy . . .

The thing about us is we’re passionate about Passivhaus. In an age of rapidly rising energy prices we need to make our buildings perform as efficiently as possible. The Passivhaus standard with its fabric first approach offers very low energy usage, comfort and quality.

We design using sustainable methodology and a firm belief in using natural, renewable materials where possible. Using the Passivhaus Planning software ensures that the exacting Passivhaus standard is met, in the most economical and sustainable way. Our designs often incorporate living roofs and wildlife habitats to ensure that the environment benefits as well as the occupants.

jonathan at work

Jonathan Williams BSc


After financing his way through university at UEA (more years ago than he cares to remember) by doing some casual building work Jonathan ended up doing this full time for the next 30 years as the managing partner of Williams & Partners, a building company which specialised in historic building conservation and the use of natural, renewable building materials.

“This approach to building conservation was born of the realisation that historic building fabric needs to breath to avoid many of the problems which have bedevilled our listed churches and houses. The same approach, allied with the use of high tech building membranes can be used to create highly energy efficient and healthy to live in, new buildings”.

janet not at work

Janet Cotterell, MSc, Dip Arch


Author and architect, with experience in designing certified Passivhaus buildings, Janet is motivated by working to produce quality, aesthetically pleasing buildings achieved through thoughtful design and teamwork with people who share common values and interests. Whilst being pragmatic about material choice she prefers natural, locally sourced products.

Appropriate use of energy is critical in today’s world and Janet believes the best way she can contribute as a Passivhaus architect is to ensure that the building’s fabric is insulated and detailed well and to ensure the whole team has a proper understanding of building physics.



Janet is the co-author of The Passivhaus Handbook

When not working Jonathan enjoys thinking about working.

When not in the office Janet enjoys taking the dog for a walk.  Hang on Janet . . .


two dogs

The Office dog's bodies

Without whom we would get more done . . . . .but less exercise.

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Passivhaus Trust Member
15 40 architecture collective
certified passivhaus consultant