Saving the planet with Passive resistance
Architect Tomás O'Leary was intrigued when he first came across the Passive House concept, and he wasted no time in building his own. Now his company specialises in creating these energy efficient homes for others.Caitriona Murphy reports
Published 05/09/2008 | 00:00
As energy costs soar, Irish householders are finding it increasingly expensive to run their households. Higher oil, gas and electricity prices mean homeowners are looking to make their homes more energy efficient.
The introduction of Building Energy Rating in 2009 means buyers will be able to compare how much houses cost to run and in a buyer's market, an energy efficient home is certain to be more attractive and quicker to sell.
Enter one of the most energy efficient houses you could imagine: the Passive House. Passive Houses rely on making the most efficient use of renewable energy and are virtually independent of fossil fuels such as oil, coal or gas.
Mention a house that runs on little or no central heating and most Irish homeowners would be forgiven for thinking it could only happen in California.
However, architect Tomás O'Leary, through his company MosArt, first introduced the concept of Passive Houses to Ireland through building the first certified project in Co Wicklow called 'Out of the Blue'. The house has been Tomás's family home since 2005.
O'Leary was first captivated by the Passive House concept at a conference in Kerry. "A Swedish architect was explaining how he designed a terrace of houses without any conventional heating system, even at temperatures of minus 40 degrees Celsius outside," recalls Tomás.
"I was blown away. I'll never forget those few minutes because I seemed to be looking at the solution to many of our energy problems in Ireland," says the architect.
"I even rang my wife, Mairead, from the conference to tell her I wanted to build a house with no central heating for the family," he says. "She thought I was bonkers and even asked me if I'd been drinking!" he laughs.
However Tomás persisted with his vision of a clean, low-energy house and threw himself into the task of researching Passive Houses. The concept is based on minimising heat losses and maximising heat gains from the home. Certified Passive Houses must meet the Passivhaus Standard, a building standard developed by the Passivhaus Institut in Germany.
Three years on, Tomás and his family live in a modern, bright, airy and energy efficient home that bears no comparison to the conventional terraced house they lived in previously.
The central tenets of passive housing are simple: reduce heat loss with insulation and by making the house airtight, and increase heat gains by taking advantage of free energy like solar power.
"We seem to have forgotten the basic first principles of building that have been around since the pyramids were built," says Tomás.
"For example, instead of facing our houses south, we face them onto the road and lose out on the huge energy potential we could be harvesting from the sun," he explains.
"Even the builders of Newgrange knew they should face it towards the winter sun." Air leaks are responsible for large heat losses throughout the home and cause draughts so air tightness is critical. "
But an airtight Passive House is not a stuffy house because of the ventilation system," he says. The mechanical heat recovery ventilation system uses the heat from warm stale air leaving the house to heat the fresh cold air coming in. The materials for Tomás's groundbreaking house were predominantly sourced abroad. "At that time most of the technology was unavailable in Ireland so things like the triple-glazed windows had to come from abroad. Now there are eight different suppliers of those windows here."
A typical Passive House generates an 85pc saving on the cost of a conventional heating and the investment required should pay for itself in seven years.
However the additional cost is not as daunting as you might expect: Tomás estimates his house cost just 8pc more than a conventional house to build. "A good proportion of the cost of a Passive House is actually substituting other costs," explains the architect.
"For example triple glazed windows were expensive but we did not have to put in a conventional heating system like radiators, underfloor heating or a boiler," he says. "The only small back up heating system we have is a pellet boiler which is carbon neutral."
The figures for heating a Passive House are astounding: Tomás says his total bill for heating and hot water is just €250 per year. Tomás and his firm MosArt have become a recognised authority on Passive Houses and were co-authors of the definitive guidelines for their construction, recently launched by Sustainable Energy Ireland.
For more information on Passive Houses, check out Sustainable Energy Ireland on www.sei.ie and MosArt www.mosart.ie.