eco design

lessons 1-4

we have been practicing  ‘eco-design’ since  long before words like sustainability and carbon emissions were commonplace 


although the details are complex, the principles of

‘green’ ‘eco’ ‘sustainable’  architecture  are simple:


lesson one : insulation, insulation, insulation

the first principle of eco-design is to insulate as much as possible:

working to the passivhaus standard suggests achieving a u-value of ± 1.0 for the major elements of the building


lesson two : airtightness

recent research underlines the importance of  good airtightness

in order to avoid draughts + control ventilation:

the passivhaus standard seeks to reduce this down to 0.6 ac/hr


lesson three : comfort ventilation [mvhr]

in order to achieve the good + healthy air quality needed, a central mechanical ventilation system is normally used, which can be made extremely efficient by adding a heat recovery unit


four : passive solar

we try to maximise passive solar gain, balanced with shading to avoid summer over-heating [we’ve all been fried inside over-heated conservatories in june]: 

passive solar depends on site, shading + orientation

lessons 5-8we generally favour the ‘fabric-led’ approach, i.e. spending most effort on the basics of insulation, airtightness and comfort ventilation, but clients are increasingly interested in the ‘active’ aspects of eco-design:


lesson five : active solar

photo-voltaic + solar heating panels generate electricity, hot water, possibly even some space-heating. 

these have longer pay-back periods than the passive approaches, although these are reducing along with their cost, and solar water heating is becoming nearly standard


lesson six : micro-generation

with the introduction in 2010 of subsidised ‘feed-in tariffs’

the various forms of generating electricity - PV’s, wind power

hydro-electric are rapidly becoming more economically viable


lesson seven : biomass | heat pumps | geo-thermal
often biomass heating provides the lowest carbon solution

everyone now enquires about heat pumps, attracted by the apparent availability of ‘free heat’. 

BUT they use electricity on a ratio of 2.5-4 :1 which is a lot of juice !

lesson eight : just do it !

govilon eco-houses


2 new houses, designed to passivhaus + Code 4/5  standards for the Brecon Beacons National Park Authority


the brief was to create two houses on a site in the village of govilon near abergavenny to exemplary environmental and design standards for future sale by the client


the design features...

- orientation to maximise passive solar gain

- verandah to avoid summer over-heating + amenity

- super-insulated floor, walls + roof

- high performance joinery

- an easily convertible attic floor

- ecological site enhancements


planning approved Nov. 2012 | completing 2017


the houses are also designed to the lifetime homes standard, ‘future-proofed’ for use by people of

all ages and abilities with minimal adaptation

wellington eco-house

this project, for clients looking for a low-energy low-cost  retirement home was designed to achieve the passivhaus standard.


planning was approved in october 2011 after a uniquely glowing assessment from the planning case officer


the design features:

- careful orientation to maximise passive solar gain

- large roof overhangs to avoid over-heating  

- super-insulated floor, walls + roof

- high performance joinery

- draft lobby / sunspaces


constructed 2013

what the planners said



This is commended, the 'simple form' with strong clean horizontals works very effectively, the steep roof pitch is also endorsed. 

A number of details are noted and complimented on, in particular the overhangs with functional exterior space beneath, screened porch, and utilisation of the garage block to interrupt the clean horizontal dominance on the North elevation.


The use of the internal space created is considered excellent, with a logical flow and layout. The feature gable window on the South elevation is considered a benefit in providing natural light into the dwelling. 

The functionality of the landing as useable space is clever, this is often wasted space in many designs we receive, however here one could imagine a piano, library, 'chill out' area, or even a home cinema! 

The use of space required for associated plant machinery incorporated into a utility room is also well thought out and 

again ensures no space is wasted



this response was not only immediate, but very gratifying, given that it is very rare for planners to  give glowing reviews of anything. More commonly, their reaction to projects needs to be carefully interpreted from the odd raised eyebrow and non-committal grunt ! our thirty years experience of dealing with planners in many different authorities means we get very such few surprises !

solar parks

In recent years we have designed a number of PhotoVoltaic solar parks, ranging in size from 0.4 ha [1acre] to 10 ha [25 acres] 


These have a planned electrical contribution to the national grid of between 50KW and 5 MW [enough power for 1000 homes]


these projects all take advantage of  either feed-in tariffs or ROC’s - the government subsidies aimed at kick-starting the photovoltaic industry, thereby contributing to renewable generation targets


the policy position changes rapidly, so anyone interested in PV installation should check the latest news


planning policies are in support of renewable generation in principle but, as always, subject to specific siting and design issues, requiring sometimes delicate negotiation with local planning authorities


our approach is to consult the lpa as soon as possible, and are finding a pretty sympathetic response, if the site is chosen carefully


we are able to model sites with our 3D modelling software, including shadowing, around the daily + annual solar cycle 


larger or more sensitive schemes require EIAs which we can assemble if required

the planning issues...

as with any large-scale renewable project. solar parks can be controversial - even roof-based pv’s can be visually intrusive if poorly designed, but solar parks, like wind-farms, raise the stakes 100- or 1000-fold


that is one reason for careful site selection and appraisal - it is beneficial for site security as well as local acceptability for pv sites to be visually screened - normally achieved through careful choice of orientation and position and retention and reinforcement of existing hedgerows


the question is often asked - should we really be covering areas of open country-side with pv’s ?

individual responses to this will be determined by the attitude to the balance between landscape protection and co2 reduction


for us ? well, we consider pv parks to be a significant contributor to renewable energy production targets - at the very least an acceptable short-term response until we succeed in reducing our energy use dramatically


by the time large solar parks are no longer required, we expect...

     • the national grid to have been de-carbonised

     • electric cars + buses to be the norm...

     • all buildings to be net-zero carbon... and probably

     •  pigs to be flying


meanwhile, solar parks are arguably the  least-worst option in landscape terms, as well as giving a good return on investment


a conversion, to low energy standards:


- highly insulated floor, walls, roof

- comfort ventilation - mvhr 

- low-impact materials, etc


the design proves that  modern, light, design can combine with energy efficiency


these images show the internal + external design, the mvhr unit and insulation details


constructed 2011

eco studio


completed near ross-on-wye in 2010, this new-build music + art studio project involved brick cladding + conventional timber -frame, upgraded on our advice to a much higher performance


this performance was modelled by aaben,  and subsequent pressure-testing resulted in an good result, given the late change in design 



- highly insulated floor, walls, roof

- comfort ventilation

- good airtightness 

- low-impact materials, etc


the design again proves that  modern, light, design can combine with energy efficiency


constructed 2010

code 3 houses | 2012


designed in 2008, these 2 houses were completed as self-builds by their new owners, and were early examples of ‘code 3’ houses

‘code 3’ was the first step on the road to ‘code 6’ - the ultimate destination of the government’s ‘code for sustainable homes’ which aims for zero-carbon homes by 2016, introduced in 2006 as a welcome long-term policy 

although the government have abandoned the Code for Sustainable Homes, there is still pressure to adopt more efficient buildings with lower CO2 emissions, with the most forward-looking local authorities insisting on the gold-standard of passivhaus. 

these houses in hereford have a number of energy-saving features...

- good insulation 
- comfort ventilation
- passive solar design
- active solar design
-rainwater recycling 

eco - projects

eco-renovation, gloucestershire
a complete renovation and extension  completed 2008, featuring external wall insulation, mvhr, innovative integrated solar + biomass heating,  huge rainwater harvesting store [ex swimming pool], and use of many benign and recycled materials. 


eco-house, monmouth
a new ‘eco-house’ designed to near-passivhaus standards, built using traditional construction and contractors, 2007. the house employed ‘lifetime homes’ standards, is fully accessible, and incorporates a lift.

waste wood-powered heat + power plant, monmouth
this multi-million pound scheme was is planned to provide
6mw of green electricity, heat and other facilities to the community of monmouth. un-built


green shop hq, gloucestershire
this 300m2 development provides office and retail hq space for the nationally renowned ‘green shop’ group was opened by jonathan porrit in 2008: with architype

eco-renovation | 2007


brockweir, gloucestershire


a major eco-renovation of a house in a beautiful wye valley location, this ambitious innovative project involved:

- total external insulation

- high air-tightness + mvhr

- bio-mass and solar heating, 

  linked in an innovative system

- low impact + recycled materials

- high level of client design input



a monmouth town centre house, designed for low energy, carbon use, and therefore running costs, with high comfort levels


designed around the aecb ‘silver standard’ to include:

- very high insulation levels

- good airtight-ness 

- a central ventilation system

- high performance windows

- a shaded passive solar ‘sunspace’

- solar water heating

- rainwater recycling


the house was built with high thermal mass and under-floor heating for continuous occupation by its elderly owner with minimal temperature fluctuation. ‘lifetime homes’ principles were followed to ensure long-term accessibility + therefore sustainability:

- through-the-floor lift 

- full wheelchair accessibility

- low sills for better visibility


the design + materials are conventional - concrete block + render + trussed roof + beam + block floor, to ensure both planning approval and buildability by a local builder 


space heating est. £200 pa 

completed 2007



wood-powered heat + power plant, monmouth


this multi-million pound scheme was proposed as the first of a chain of community level ‘eco’ power stations, providing 6mw of green electricity and heat to the community of monmouth


the conversion of a 1.1ha warehouse was planned to include a spa, cafe, and green retail space


project currently in abeyance