Energy people: The passive homeowner

“Why would you build any other way?” is Niall Walsh’s stock answer to questions about his passive house.

His family home at Mount Merrion in south Dublin looks no different from any other on Wilson Road, which mainly features 1930s-style bungalows. The house that Walsh and his wife Michelle built three years ago conforms to the appearance of its neighbours. There is a central porch, a sitting room to one side and a master bedroom to the other. The Walsh family even re-used red roof tiles from the original 1930s house on the site.

There the similarity ends, however. Behind the Walsh front door is about 3,000 square feet of tiled warmth, evenly spread throughout the house.

A large, split-level reception area at the back of the house which incorporates the kitchen and television areas is warmed by two radiators which Walsh says never need to actually get hot.

Temperatures in the radiators and the rest of the house are maintained by an air-source heat pump, an energy-efficient device which involves a compressor and a condenser to absorb heat outside and release it indoors – “an air conditioner in reverse”.

Windows are triple-glazed. In a conventional house, draughts and ventilation change the entire air about six times in an hour. In the Walsh house, this is reduced to about one air change every two hours. Heat from electrical appliances remains in the house longer, and when warm air is expelled it passes through a controlled heat exchanger, to warm cold air on its way in.

The result is a house which delivers annual room and water heating – for four adults – at a cost of €170 per year. Electricity brings the total cost of running the house to about €2,000 a year, he says. The total cost of building his house was in the region of €700,000.

Are there health implications of living in effectively an airtight, insulated box? “Yes,” he replies. “Nobody in this house has had a sniffle all winter”.

The house at Mount Merrion was recently used by the Passive House Association of Ireland to host an information evening for members of Dún Laoghaire-Rathdown County Council. A week later the councillors voted to amend their draft development plan to stipulate that in future all buildings in the council’s administrative area of South County Dublin, both commercial and residential, be built to passive-house standards.

Chairman of the Passive House Association and University of Ulster lecturer Dr Shane Colclough says passive houses are now more mainstream than “hippy”.

At a conference last November, stands were taken by Irish firms already committed to working to low energy standards. These included Kingspan, Munster Joinery, and AIB, which has a €100 million energy fund for small and medium enterprises wishing to reduce energy bills.

The Passive House Association of Ireland will hold a briefing on passive houses at the Dundalk Institute of Technology, on Wednesday March 11, from 5pm to 7.30pm. For details see phai.ie