Passive home to slash energy costs

A ‘passive house’ might sound like one devoid of the normal domestic hustle and bustle but the only thing absent from the O’Leary family home is a heating system.

No cowboy builders are to blame, however. Tomas and Mairead O’Leary deliberately chose to say no to radiators, fireplaces and oil tanks and let nature - and some nifty design - warm their hearts instead.

There are 7,500 certified passive houses but the house the O’Learys and their three children share at Ballykeppogue near Wicklow town, is the first in Ireland and as the prototype, provides the ABC to passive house building.

Insulation is the key feature. Where most homes have about two inches of padding in the walls, the O’Leary’s house has around 12 inches lining the walls, attic and floor and windows are all triple-glazed and super-sealed into the frames.

To make the most of the sun, the main rooms and windows are south-facing, and there are solar panels on the roof to heat water.

The idea is that all the heat generated naturally by sunlight, body temperature, light bulbs, cooking and showering is captured within the house where most normal homes would haemorrhage it through cracks, crevices, under-door gaps, windows and poorly insulated surfaces.

A special ventilation system allows a complete change of air in the house 12 times a day so it doesn’t get stale or damp and as the warm air is expelled, it heats the incoming air from outside so that the temperature indoors doesn’t dip.

It may be green and carbon free but is it a practical family home?

“The air temperature is around 23 degrees consistently,” says Tomas. “Since we moved in we had one night when the temperature outside fell below five degrees but the lowest it was inside was 22 degrees.”

The specialist nature of the construction means higher building costs but still Tomas says the average passive home is only 10% more expensive to build.

“Over the life of the mortgage, it will be a lot cheaper to run. It’s not unusual for families to spend €2,000 a year on heating. Even if energy prices stay at current levels - and we know they won’t - over 20 years that’s a saving of €40,000.”

The RTÉ series, About The House, visited the house last year when it was still being built and the O’Learys have now moved in. The return will be broadcast on November 22 on RTÉ 1 at 8.30pm.

The Energy Research Centre at UCD is planning to attach monitors around the house and track its performance over two years.

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