The "most sustainable mainstream house" in the world has just been built by an Irish company on a research site in England.
Irish building manufacturer Kingspan Century claims that its zero-carbon "Lighthouse" on the BRE (Building Research Establishment) plot in Watford has a level of energy efficiency that is unrivalled in houses of its type. It was built to show that advanced sustainable homes can be constructed by and for most people.
The house costs just €50 a year to heat because it has highly insulated walls, makes it own electricity and hot water through the use of solar and PV (photovoltaic) panels on the roof, stores heat in its floors and ceilings, uses a wood-pellet boiler and benefits from passive solar gain through rooflights and windows.
Other features include rainwater recycling, A-rated (low energy) white goods in the kitchen, a draught lobby to negate the need for a tumble dryer and low-energy light bulbs.
The 93.3sq m (1,004sq ft) house complies with the British government's code for sustainability, energy efficiency and carbon emissions which all housebuilders have to comply with by the year 2016. The requirements are around 100 per cent more stringent than current Irish building standards, says Kingspan Century.
"We have shown that an Irish company is capable of producing a 2016 house today. It is achievable, so why are we delaying doing this when it has been proved that it can be done," says Gerry McCaughey, chief executive of Kingspan Century which has offices in Ireland and the UK.
He also criticises the fact that it is not possible to sell home-generated electricity back to the ESB. "In the 'Lighthouse', if you go on holiday for two weeks you can generate electricity and give it back to the electricity companies. You can't do that in Ireland."
The house was designed by architects Sheppard Robson who configured it as a lifetime home that would be flexible enough to cater for changing family needs.
The bedrooms are on the ground floor where less natural light is needed. This enables the top floor, which soars skywards like the sail of a ship, to benefit from natural light coming in from above and the shape makes optimum use of the windcatcher on the roof which ventilates the "airtight" building. Heat from the boiler warms this incoming air while stale air can be expelled without cooling down the house.
There are slatted timber shutters on the windows to cut down on solar gain when the need arises, especially in light of the fact that the planet is gradually getting hotter, says Dan Burr, associate partner and design director of Sheppard Robson. A mezzanine in the roof space can be used as a home office - cutting down on commuting - and the half of the roof area over the sittingroom could be converted into another bedroom without having to add on to the house.
The shape of the house, which is clad in sweet chestnut, was inspired by the traditional barn, says Burr. "We reinterpreted it as a contemporary design." The architects liked working with Kingspan Century's panel-based system.
"We saw many pod-based systems that limit the design and tend to result in boxy prefabs," says Burr. "The shape of this building is a natural form that tends to have universal appeal. Every planner should be dragged here to see it."
