The UK's Best Green Homes: Part One

The 'Massive' House

Details: Self-build, Sussex
Designer: SEArch Architects (01406 364646)

An exacting proportion of thermal mass to insulation – together with careful orientation – has helped architect Dr Jerry Harrall create his innovative low-resource home. The thick walls of this earth-sheltered house are constructed of 300mm solid concrete panel with 200mm reinforced concrete for the roof and floor, with insulation – 140mm extruded polystyrene – throughout. This dense construction facilitates thermal mass, meaning the structure absorbs and stores heat entering the house through south-facing glazing — and slowly releases it when temperatures fall. It also helps capture incidental heat – from appliances and human occupation – within the structure. Natural lime render and clay interior paints also increase thermal mass.

Unlike many new airtight, mechanically ventilated homes, careful design allows for natural, no-energy passive stack ventilation and passive cross ventilation, ensuring a healthy internal environment — while also preventing the house overheating in summer.

The natural roof – with 600mm of soil which supports ivy growth – also helps regulate internal temperatures. Ivy growth over the earth-sheltered north-facing façade, together with minimal glazing, reduces heat loss from this elevation, and shelters the low-lying home from the wind.

Solar thermal panels provide hot water, but Jerry maintains that developing low-cost, low-technology and low-maintenance solutions to reduce reliance on resources is the essence of creating a sustainable build: “Renewables should be supplementary,” he comments.

Jerry’s own revolutionary home has become a benchmark for his work — from which he has honed the propo - rtion of thermal mass to insulation to create even more efficient builds.

The Future-Proofed Home

Details: Self-build, Cotswolds
Designer: Tranquility Houses (tranquilityhouses.com)

This self-build’s rainwater harvesting system is so extensive that owner and green pioneer Mike Hillard was able to offer his local council 12,000 litres when floods devastated clean water supplies. Below the three storey, stone-faced home lies two storage tanks, with a combined capacity of 24,200 litres — enough to provide seven months’ supply of both drinking and non-potable water. More importantly, the house contains watersaving features to reduce reliance from the outset.

Equally impressive are Mike’s annual energy bills — which equate to approximately £67 for heating and hot water. Low Grid reliance is due, in part, to the 158m² double-height glazed sunroom — its extensive concrete floor acts as a thermal store. Roof-mounted solar thermal panels (ABOVE) also provide energy to heat domestic water. Mike, who runs sustainable British wood flooring company Tranquility, hopes a community wind turbine will enable him to become entirely self-sufficient.

The Pioneer

Details: Self-build, Wales
Designer: Eco Arc (01539 822822 ecoarc.co.uk)

Hailed as one of the UK’s original eco homes, this self-sufficient 2004 self-build remains an outstanding example of how strong design and sustainability go hand-in-hand.

The timber frame is insulated with 300mm of blown cellulose fibre (recycled newspaper), while the striking double-height glass frontage – constructed from low-E triple glazing – encourages passive solar gain. Inside, a 150mm-insulated concrete slab floor provides thermal mass. This, together with high levels of insulation, means the large home only requires a woodburning stove for space heating.

Electricity for this self-sufficient house is provided by 20msup2; of solar photovoltaic (PV) panels – mounted upon garden trellis – and a 2.5kW wind turbine (with a 12kWh battery store as backup), while roof-mounted solar thermal panels provide hot water. Rainwater is collected and purified to provide both drinking and non-potable water, and waste is treated on site through a sewage treatment plant, which discharges to a reed bed.

In addition to creating a low-resource home and generating energy on site, the homeowner, keen to build a home with low embodied energy, planted ten times the number of trees used for the timber frame, and recycled materials from the dwelling which previously stood on the site.
Read more about this self-build.

Read about a pre-war renovation, a low-carbon remodel and a sustainable urban self-build in part two...

More green homes:

• An Energy-Efficient Self-build by the Coast
• A Low-Impact Eco-House
• An Eco-friendly Farmhouse with a Swimming Pond

Further reading:

• How to Build a Sustainable Home
• How to Build a No-heat Home
• The New Standards, and How to Achieve Them