When you picture an eco home, it’s only natural to imagine something along the lines of a timber-clad dwelling with a green roof – but a house’s green credentials aren’t always obvious at a glance.
Advancements in construction technology, ranging from whole build systems to components such as glazing, mean that the desire to produce a highly energy efficient dwelling no longer curbs your design choices.
For some, it’s not enough to build a thermally-efficient home. Many people also want the materials and labour used to be as sustainable as possible – obtained locally from renewable sources, for instance. This minimises the amount of energy that goes into the construction of their home (known as embodied energy).
Learn more: 10 Steps to a Green Home Renovation
While some of the following dwellings employ significant amounts of resource-intensive materials, such as concrete, they have all achieved outstanding in-use energy performance levels – meaning they are able to repay their carbon debt over the years to come. Read on and discover a variety of ultra-efficient houses that will inspire your own sustainable homebuilding project.
This homeowner wanted to build an ultra-efficient, accessible house that would fit in with her long term retirement plans.
After learning about Passivhaus design through a friend, she hired Eco Design Consultants, and met with the director, Alan Budden, who was appointed to handle the plans for her new home. Together, they managed to convert her planning-approved proposal into a Passivhaus without losing the traditional aesthetic. The designers Used the Passive House Planning Package (PHPP) software to modify the specifications to meet the high performance standards.
Build cost: £453,000
House size: 201m2
This couple set themselves the ambitious target of building a sustainable home with net-zero utility bills. They collaborated with the German company Huf Haus, who helped them realise their vision of an energy-efficient premanufactured home.
The house has triple glazing, underfloor heating, a heat pump and excellent insulation. But adding a 10kW array of solar electric panels, 12kW of storage batteries and LED lighting meant the home achieved its zero-bills aim.
Build cost: £1,510,000
House size: 317m2
EXPERT VIEW: Advantages of timber frame for a sustainable self build home
Cameron McQuillian from Rob Roy Homes gives his top tips on how timber frame construction can deliver the sustainability and performance levels you want:
Cameron McQuillian is project manager at Rob Roy Homes, with a focus on sustainability and low-carbon production methods. Rob Roy Homes specialises in the design and manufacture of bespoke timber frame buildings and is an STA Assure Silver Member.
This characterful oak frame dwelling combines traditional and modern construction methods to produce a home that is comfortable throughout the year and filled with a timeless appeal. The owners sought to source trades and materials from the surrounding area to produce a home that was self-sufficient in its energy use and efficient in its use of water.
An engineered timber frame was combined with hempcrete. Comprising the inner woody core of the hemp stem and a lime-based binder, hempcrete is a natural, breathable and thermally-resistant material.
Build cost: £495,000
House size: 322m2
Need more advice on building an eco home?
On 22nd July 2021, Chris Bates, Editor of Build It, will be hosting a virtual discussion with some timber frame specialists, about the eco and sustainability credentials of timber construction.
The FREE webinar will look at all aspects of eco building, including design, energy efficiency, structural systems and airtightness.
The Smiths used straw bales with a lime render to achieve a highly sustainable home on a tight budget. A large south-facing pitched roof allowed the couple to install plenty of solar panels to provide their electricity. The supporting timber frame was constructed from reclaimed wood, adding to the abode’s eco credentials. Local trades and products were used wherever possible. Even the lime paint and handmade furniture were obtained nearby.
Build cost: £210,000
House size: 200m2
This woodland dwelling’s heavy internal concrete structure is designed to make the most of the passive solar gain enabled by the large spans of glazing. Even in mid-winter the house is able to capture the sun’s warmth. High insulation levels were specified for the ground floor, external walls and roof.
The windows are double glazed and fitted with a reflective, insulating film in order to trap solar heat. Most of the construction materials were locally sourced, including the rough sawn oak-cladding used on the external elevations. This keeps the embodied carbon of the property to a minimum.
Build cost: £240,000
House size: 200m2
John and Jeanette Fenwick opted for a highly insulated timber frame with a blockwork outer skin and triple-glazing to ensure their award-winning project met Passivhaus standards. Warmth generated by solar gain and activities such as cooking is recirculated throughout the building by a mechanical ventilation and heat recovery (MVHR) system. An air source heat pump (ASHP) warms the property’s domestic hot water supply. This results in annual energy bills of just £400, despite the Scottish Highland location.
Build cost: £387,214
House size: 239m2
After years living in an inefficient, draughty home, Trevor and Judith Gospel decided to build one of the first Passivhauses in north east England. The process went smoothly, including the installation of non-standard, load-bearing polystyrene insulation for the ground floor. The masonry cavity wall construction features 300mm-thick Rockwool insulation, while the roof space contains 500mm of recycled paper.
Build cost: £307,350
House size: 166m²
Despite the traditional exterior, creating an energy efficient modern home was a top priority for the Searles. They installed extra insulation in the roof, a mechanical ventilation heat recovery (MVHR) system and wet underfloor heating (whereby lower operating temperatures allow for greater efficiency than with radiators).
The triple-glazed softwood windows have low U-values, too, ensuring that this traditional weak point in a home’s thermal performance keeps energy loss to a minimum.
Build cost: £548,398
House size: 313m²
Andrew and Elaine Torrance’s new home offers the accessible and comfortable environment they were after and keeps energy bills to a minimum. Warmcell, a cellulose insulation made of recycled paper, provided an eco-friendly way to make the engineered timber frame thermally-efficient. The windows and doors are timber and triple glazed with a powder-coated aluminium cladding, so they require little to no maintenance.
Build cost: £274,980
House size: 194m2
By prioritising the structural fabric of their self-build, the Hurds now benefit from a low energy property with a traditional exterior and a more contemporary interior layout. The timber frame system used offers excellent insulation and substantially reduced thermal bridging.
The house is so well insulated and airtight that the Hurds didn’t have to install a conventional central heating system. Instead, they have a woodburning stove with a back boiler to heat water, which feeds three radiators in the communal living spaces via a thermal store in the basement.
Build cost: £504,315
House size: 320m²
Determined to use renewable materials wherever possible, Kim Siu opted for a timber frame structure, straw bale insulation and locally grown larch cladding. Not only was this a sustainable approach but it also helped make the new home blend into its surroundings. The prefabricated timber panels were craned into place with the straw sealed inside.
Build cost: £169,000
House size: 140m2
A 657m2 brick-clad farmhouse might not scream sustainability on first glance, but despite its size this impressive dwelling uses relatively little energy. This is thanks to the Beattie Passive system. The method creates a sealed envelope, consisting of an insulating foam filled void, around the whole house. This eliminates cold bridges and provides excellent airtightness, allowing it to achieve Passivhaus status.
Build cost: £1,950,000
House size: 657m2
Adament that they wanted to spend less on bills, this couple hired an architect from The Green Register and set about designing a self build home steeped in eco-friendly features. The scheme was built with Passivhaus principles in mind; with a south facing structure to maximise solar gains and prefabricated walls which came installed with air-tight insulation. The pair even re-used materials from the site, such as old scaffolding planks, for an ultra efficient and equally sustainable build.
Build cost: £445,586
House size: 344m2
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