A new home in County Westmeath, Ireland has became energy positive for the second year running - meaning that it produced more energy than it actually used, resulting in a surplus of energy and the overall carbon negative rating.
Designed and built by Irish technologist and energy specialist Patrick Daly, the house is located near Mullingar and features a highly insulated and airtight timber frame construction.
According to a report in Green Building Press, Daly began to build the house in February 2008, moving into it in September 2009 with his wife and their three children.
Most of the house's heating comes from the sun, directly or indirectly. Back-up heating is also provided by a small heat pump via a heat exchanger into the air supply system. This heat pump then provides back-up hot water alongside the solar water heating.
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Daly told the press that he had intended to build an environmentally friendly 'eco house'.
'In the early design stages, I focused on ensuring that the house had good passive solar features balanced with a rurally sensitive design. As the technical design progressed, I began to examine the possibility of zero energy as a target and felt confident that it could be achieved,' he said.
'In essence, the house used passive house principles and targets to achieve an ultra-low space-heating demand. I then sought to radically reduce the remaining energy loads through additional energy-efficiency measures and to meet them from renewable sources.'
Daly explained how the extra energy produced at the house is sold back to the Irish electricity grid.
Said Daly: 'Depending on extent of solar radiation, the house is either importing or exporting electricity. The electricity we generate we sell back to the grid, at a poor rate compared to other EU countries, but it is close to what we are charged per unit, so effectively we export a similar amount of energy as we import. Thus our energy bill is very low – only the standing charge for the service, really.'