Winner of the Passivhaus Awards 2013 for Best Private House

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Low Energy Design

One of our core responsibilities, as your architect, is getting the building fabric right for low energy performance, and at CTT we take this as an essential starting point.

From achieving the certified Passivhaus low energy standard, to an award-winning B&B and community building (in a highly sensitive historic setting) CTT Sustainable Architecture bring performance and design together, perfectly.


CTT Sustainable Architecture is the new name of Cotterell Thomas & Thomas LLP. CTT's approach to architecture is to bring together design flair with a sustainable, low energy focus.


Low energy building solutions are sometimes accused of lacking uplifting design - we believe both can be successfully achieved, producing low energy buildings that respond appropriately to their context (both physical and historical) and contain light, calm and uplifting spaces.


CTT prefer the use of natural, healthy materials and by designing using Passivhaus low energy principles our buildings will also be comfortable, and healthy for their occupants, and inexpensive to heat.


CTT work in a collaborative style, it is your building and your investment after all. We adopt the same team approach with all those involved in the building process, and especially aim to work closely with the chosen contractor.



Read more about the CTT team and their methodology...

Architects specialising in low energy design and Passivhaus

This 1970's retrofit (including a new build extension) is one of the first retrofits in the UK certified to the full Passivhaus standard. The project  won the UK Passivhaus Awards 2013 for best private house.


Please click on the photos, opposite, to view at a larger size.


Learn more about the transformation on the popular "Passivhaus Refurb" blog.


View more photos from the project here.


See an interview with our client on site, featured on BBC Spotlight, via YouTube.

Featured Project: Totnes B&B in Devon

What is Passivhaus?

Passivhaus is a building methodology that targets reducing the energy needed for heating by 90%, while maintaining a comfortable indoor temperature and ensuring healthy indoor air quality, all year round.


Our design service is combined with the latest PHPP energ modelling tool. PHPP is the only proven software that accurately predicts the energy savings that will be achieved by a building.

This early modelling optimises your build costs as well as ensuring we deliver lifetime savings on your energy bills.


By working as an integrated team (see our joint venture for housing at www.passivhaushomes.co.uk) we are best placed to deliver quality, low energy and comfortable buildings at economic costs.



Read more about the Passivhaus Design standard....

The Passivhaus Handbook

Janet Cotterell, the founding partner of CTT, is co-author of The Passivhaus Handbook the first comprehensive book on Passivhaus.

Buy the book from Green Books direct and get a better price than Amazon...

See details of our latest completed projects...

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Award-Winning Sustainable Architecture by CTT


Less Energy



See details of our latest completed projects...

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