Some retrofitted homes performing below their efficiency rating, Oireachtas told

Findings could mean homes would have to be retrofitted again after 10 years, researchers say

Some homes in Ireland which have been retrofitted to a highly efficient A2 standard are actually performing at a far less efficient C level, new research has found.

It could mean that retrofitted houses might need to be retrofitted again in 10 years, an Oireachtas committee has been told.

Projects undertaken by a climate emergency research group at UCD’s school of architecture have identified a performance gap in houses retrofitted to a near zero energy building rating (NZEB).

Lead researcher for the group Dr Oliver Kinnane told the Oireachtas Committee on the Environment and Climate Action on Wednesday that the actual performance of some of the retrofits did not live up to the NZEB rating.

“In some cases A2 homes are performing at C levels, he said. About 50 per cent of fabrics are not meeting design U-values and heat pumps are underperforming due to improper installation.

“It is important we get retrofit right, to avoid retrofitting the retrofit in 10 years time,” he said.

Asked later by committee members as to why these retrofits – which constitute a minority – were falling short of standards, he said that among the issues were mis-sizing of heat pumps, incorrect installation of heat pumps, as well as a lack of insulation on piping and poor insulation materials generally.

He said there was also heat and energy loss because of thermal bridging and thermal bypassing (at junctions such as windows) as well as other design and construction faults.


He told Réada Cronin (Sinn Féin) that other mistakes by contractors included the use of impermeable insulation that trapped moisture and allowed mould growth and dampness, and also created problems such as bad air quality.

He said that the problem stemmed from a “lack of knowledge and a lack of training.

“It emphasises the point that we really need to train the installers ahead of installation,” he said.

Saying such skills were not something that every contractor had in their armoury, he added the industry needed to be trained or otherwise builders would be pulling those retrofits apart again in 10 years.

Pat Barry of Irish Green Building Council told the committee that the construction emissions actually amounted for 37 per cent of all emissions in Ireland, which put it on a par with agriculture.

Mr Barry said that at the moment construction emissions were measured at 23 per cent but that only took account of operational transmissions. However, when embodied carbon emissions (associated with production of construction materials, transport of materials, construction process, maintenance, repair and disposal of buildings and infrastructure) was included it added an extra 24 per cent.

The Irish Green Building Council was founded by organisations operating in the construction and property sector, to accelerate the transition to a sustainable built environment.

Mr Barry and Dr Kinnane both argued that it would be far better from an emissions perspective for the State to use as much of the existing building stock as possible (including vacant homes) rather than demolishing and doing new construction in all cases.

Both also talked about the desirability of Ireland producing its own bio-based building materials such as timber and hemp, rather than concrete and steel. Hemp can be used for insulation and also as part of a cement alternative.

Mr Barry said: “Biobased materials require lower CO2 emissions to produce and sequester carbon. Only 24 per cent of newly constructed homes in Ireland are timber frame versus 75 per cent in Scotland,” he said.

“This requires encouraging and supporting new local forestry and agriculture related industries to supply the construction sector. Forestry licensing must be reformed to increase levels of planting.”

Vacant buildings

Dr Kinnane said that current retrofit rates are well below the levels required. On the use of old vacant buildings, he said: “We are constructing many new buildings, but we are also demolishing buildings to make way for replacement buildings.

“Young buildings, built only 30-40 years ago, are being demolished all over the city and country to be replaced by buildings of much greater floor area and materials of high embodied carbon. The service life of buildings is constantly decreasing. This is unsustainable.

“We need to save the buildings we have and retrofit first.”

Mr Barry also made the point that it was important that the one-stop-shops – that will form the core part of the Government’s national retrofit scheme – will not be led by construction companies alone but also include advisers who can give them independent advice.