Late 2000s to Date



A Passivhaus retrofit and extension of Grove Cottage, a 98 m2 Victorian detached house in Hereford dating from 1869.

The house was in need of total refurbishment. Basic strategic advice on thermal design was provided to the owners, who are themselves architects, on the external insulation, the ‘cavity’ insulation in the 25-50 mm gap between Grove Cottage and the adjacent detached house, the passive solar measures in the extension and essential details of the space and water heating system, including very well-insulated tank and pipes. Also some input on the use of more energy-efficient lights and appliances.

The first UK retrofit to be certified to the Passivhaus Institut’s Enerphit Standard. Short listed, 2012 Passivhaus Trust Awards. More information on the owners’ website and in this article in The Independent.





Grove Cottage, Hereford.


Picture © Simmonds Mills Architects.




New detached house in Cropthorne, Worcestershire. The clients wanted near-autonomy in energy use. EAA was appointed to work towards this goal with Neill Lewis Architects. Close to zero backup space heat requirements, aided by extensive passive solar design features.

Hot water comes from solar. Water comes from rainwater collection. Electricity is interchanged with the national grid. Over a year, solar PV generates more than the house consumes.

The floor area is 144 m2 plus a porch, ‘mezzanine’ and cellar. The shape took careful negotiation with the planning authority because the house’s footprint straddles the village development boundary.

It went through the 2011-12 winter needing about 500 kilowatt-hours of backup space heating energy. Energy performance in winter 2012-13 was better because the mechanical ventilation system was complete by then. In the rather mild winter 2013-14, it used negligible space heating.

Overall winner, Wychavon Council 2014 Intelligently Green Awards.

More information on the owners’ website. David Olivier’s September 2012 article in Self Build and Design is here and another article is here.


Cropthorne SB&D Cover

The Autonomous House, Cropthorne.

Front cover of Self Build and Design magazine, September 2012.

Picture © M. Coe.


Internal view on the first floor, facing west.







Internal view on the first floor, facing west. Much of the dwelling’s winter solar gain enters through the large window to the left. Note, the main living rooms are located on this level.

Picture © EAA.


Cropthorne House Cropthorne NE Side

Left, viewed from the south-west.

Picture © M. Coe.

Right, viewed from the north-east.

Picture © W W Magazines Ltd.



A self-build project in south Wales. The village has no natural gas. The advice provided concerned the heating and ventilation services and electricity savings on lights and electrical appliances. The thermal envelope was already quite well-constructed, having used an ICF system, and the windows were virtually on order. The suggestions on the space and water heating system saved the owners about £2,500 on capital cost and reduced the house’s prospective CO2 emissions.


A Grade II Listed barn conversion in rural Herefordshire, attached to a 16th century Grade II Listed oak-frame farmhouse. A mix of solid limestone and oak-frame construction. Efforts are being made to renovate it to AECB Silver Standard or above and to deliver affordable heating costs on a site with no natural gas. It is hoped that the insulation and draughtproofing measures will reduce the building’s space heating consumption two- to three-fold, compared to just meeting current Building Regulations.


An energy-efficient retrofit of a suburban detached house in Hampshire. Advice to the owners and their architects on how to evaluate correctly the relative heating costs and CO2 emissions of a space and water heating system based on:

  • a natural gas condensing boiler;
  • an electric heat pump with top-up resistance heating; or
  • wood pellets.


An ‘annexe’ in the garden of a Grade II Listed historic house in Oxfordshire. Several novel solar technologies are included, with the details based on past US experience. The rest of the house will meet the Passivhaus Standard. Currently at design stage.


Grade II Listed 16th century solid stone building, Oxfordshire. In mixed commercial use, including office space, a museum, a library and a small café, all. Half-day survey and follow-up report on a strategy to reduce gas consumption for space and water heating and electricity consumption for lighting, ICT equipment, portable space heaters, storage heaters, water heating and catering.

The building is cold and draughty. All its space heating comes from electric systems and old gas convector heaters, with high CO2 emissions per unit of heat. The suggested long-term plan would insulate the building fabric internally and substantially improve comfort for the users, but without changing the building’s appearance or significantly increasing space heating greenhouse gas emissions.

Further proposals were made to update the 35-40 year old lighting, which is very energy-inefficient. Electricity consumption should decline after implementing this advice; i.e., implementing more energy-efficient lighting and equipment and switching to gas for space heating. The charity which owns the building is now considering the options for major refurbishment and for implementing the list of recommendations.


A replacement dwelling in a small market town in the Midlands. Had aimed for very near to the Passivhaus Standard. Expert advice to the owner on the design proposals which had already been commissioned from a local architectural firm.


Another replacement dwelling in a Midlands city. Construction work was well underway before advice was taken on energy efficiency. Nevertheless, significant improvements are being achieved to the fabric insulation, the space and water heating system and the electrical equipment within the building.