With BIM and the NZEB new-build requirements in 2020 typically being the focus of the AEC industry, one area that may be slightly overlooked is the state of existing Irish housing stock, as well as the difficult demands associated with undertaking deep retrofit responsibly.
CO2 emissions from the residential sector are a cause of major concern in recent years, with the SEAI indicating that Ireland’s CO2 emissions are almost 60% higher than the EU average. Irish homes’ CO2 emission levels had steadily declined between the period of 2005 to 2014, but increased by 7% between 2014 to 2016. 
Similarly, the Climate Change Advisory Council have recently warned that Ireland is not set to meet its EU 2020 commitments and will struggle to decarbonise its economy by 2050; potentially facing fines of hundreds of millions of euro because of this.
This means that the area of deep retrofit could become more prevalent soon, with the EU’s Roadmap 2050 targets seeking to reduce CO2 levels by 80-95% from 1990 levels.
Ireland’s Housing Stock
‘Ireland’s housing stock has been identified as being amongst the least energy efficient in Northern Europe.'
The Irish Government did not introduce regulations in relation to energy efficiency until 1979, with 50% of the current housing stock built prior to this. Significant thermal retrofits were not introduced until 2006, meaning most Irish homes are thermally inadequate.
Similarly, according to the 2011 census, of the 2,000,000 dwellings in the country, 930,000 were built before the first Irish Building Regulations. A further 750,000 were built before any thermal insulation requirements. Arup predicts that 70% of current buildings will still be in use in 2050 and have stated that if every new building constructed is carbon neutral, that Ireland will still fall short of the emission reduction targets, unless the existing building stock is upgraded.
There are indications that the situation in Ireland has not seen much change since the 2011 census. During the annual report from 2017, the CSO stated that of the BER certifications produced, the most common BER ratings achieved by domestic dwellings are a C3-BER rating and a D1-BER rating, both at 13%. A total of 53% of BER ratings have a D1-BER rating or worse. A total of 10% of homes have a B3-BER rating or better, with only 1% A-Rated.
The SEAI indicate that 25% of CO2 emissions in Ireland come from the residential sector alone (Figure 2.2). Professor J. Owen Lewis states that ‘Our homes account for more than a quarter of Irish energy-related carbon emissions. How we use energy in our dwelling is for most of us, the most tangible and direct impact we have on Ireland’s greenhouse gas emissions.'
According to the SEAI, ‘Extensive retrofit measures of the existing building stock will need to be undertaken in order to reduce the excessive carbon emissions from Ireland’s existing housing stock, with the EU setting out targets in Roadmap 2050 to cut greenhouse gas emissions by 80–95% by 2050 compared with 1990 levels.'
According to the UK Government, with respect to a European scale, Irish homes have the third highest annual energy consumption rate per dwelling.
The SEAI have also shown that Irish homes consume more energy than both the UK and EU averages.
The average Irish dwelling emits 47% more CO2 than the average dwelling in the UK and 104% more than the EU-27 averages. Similarly, a report produced by the SEAI, indicates that Ireland produces more kilo tonnes of CO2 per dwelling than both the UK and the EU averages.
However, it stated that Ireland also had the 4th greatest percentage of energy efficiency improvements in the EU between 2000 and 2010. Although this may say more about the state of the existing housing stock rather than extensive retrofit measures being undertaken.
For Ireland to meet its Roadmap 2050 commitments, extensive retrofit measures of the existing housing stock will be necessary. Depending on the dwelling, some extreme energy-saving measures may need to be undertaken to achieve the energy reduction targets. For example, the removal of existing chimneys and the replacement of existing un-insulated concrete ground floor slabs have high-cost and high-disruption implications but may be crucial in some homes to meet Ireland’s 2050 commitments.
The BRE are investigating the dangers of leaving existing floor slabs in deep retrofits, with concerns it can lead to insufficient radon protection and could potentially subject occupants to radon poisoning. Secondly, industry specialists in deep retrofit could become extremely in demand as Ireland attempts to decarbonise its economy by 2050. For retrofitted proposals to be analysed responsibly, analysis such as a hygrothermal analysis, a condensation risk analysis, and thermal modelling may be necessary to ensure that the proposed solutions do not present a risk in terms of condensation and/or mould growth, and thus, will not present a risk to the occupant’s health.
Competencies in accurately assessing the existing and proposed dwellings CO2 emissions (kgCO2/m2/yr) and energy consumption levels (kWh/m2/yr) through software such as DEAP and the PHPP could also become crucial.
This could present a massive opportunity for both architects and architectural technologists to specialise in this field.
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