As part of the Energy Performance Survey of Irish Housing, which was completed in 2005, energy auditors assessed 52 houses designed to the 1997 version of Part L of the building regulations, which sets minimum levels for insulation and heat loss. Only one complied in full.

Details of the survey, which is yet to be published by Sustainable Energy Ireland, are revealed in an article in Construct Irelandmagazine.

Potentially making a bad situation worse, the insulation standards of the 52 houses may be lower than the survey reveals, as the assessors could not get a complete energy performance picture of the houses they visited, with particular aspects such as floor insulation.

"That was one difficult area we had, " said Gerry Wardell of City of Dublin Energy Management Agency, which coordinated the survey along with DIT. "They were non-invasive studies so we weren't able to drill a hole in the floor to check if the correct insulation was put in. In the walls, to a large extent, we were able to peep in through the openings for the services, the wiring and the plumbing and all that. That speaks for itself. There was an opening there we could see through - it wasn't sealed.

"In the attic where the insulation was at ceiling level we could check it very well and where it was in the sloping part of the roof sometimes we could and sometimes we couldn't. But overall we felt we got a fairly good handle on it."

Wardell is careful to stress that, in many cases, a house's non-compliance may have been due to a technicality rather than inherent problems with insulation levels:

"Compliance with Part L involves taking every last detail and giving equal weight to points which are more important and to the ones that are less important. For example, if a house failed on no draught stripping on the attic hatch door then it would fail, whereas more serious things would be if the insulation was left out over large areas of the walls.

"Normally when people talk about complying in Ireland what they've meant is, 'is the insulation in?' That's the main area that people judge it by, and if it's the right thickness.

To comply then there are other little clauses and subclauses, such as sealing the attic hatch.

The pipes going up through the hot press into the attic as well should be sealed, and generally they're not. Most houses would fail on that."

According to Wardell, the ideal way to rate a building accurately would involve inspections during the construction process. "Ideally you'd go along and see them pouring the floor slabs, you'd go back again when the walls are going up and when they're being completed. In an ideal world you'd do an infra-red survey then on at least a small percentage of houses and a blower door test on a small percentage of houses."

In the UK, blower door tests, which measure the draughtiness of buildings, are to be used to check compliance with energy regulations for all new homes. In spite of such a low level of compliance, the Department of the Environment cannot refer to a single prosecution of a builder, developer, engineer or architect for failure to comply with Part L in the history of the state.

"The enforcement of the building regulations is primarily the responsibility of the 37 local building control authorities, " said a spokesperson for the department. "A breakdown of enforcement action for each part of the regulations is not available in the department. However, each building control authority has been requested to include this information in future statistical returns."

According to a local authority building control inspector, who wished to remain nameless, the regulatory system is full of problems. "The building control set up in this country is basically papering over the cracks. It looks good, it's supposed to look good, but the defects are there when you go down into it."

Although inspectors are expected to check between 12% and 15% of new homes for compliance with regulations, the emphasis is not on comprehensive checks. "Even if you go in and inspect a building you cannot do exhaustive inspections to ensure that everything is correct, " said the inspector. "You take elements of the building and inspect those. You're relying on the fact that it is a self-policing, self certification process."

With the government placing the onus on architects and engineers to certify homes they have designed, the inspector is not surprised that noncompliant buildings slip under the radar. "When you get into a self-certification process, they're not going to say 'our work is deficient'. No one is going to say 'we're bad at our job, we don't do things right'."

Jeff Colley is the editor of Construct Ireland, now in newsagents nationwide