The cost of retrofitting Dublin City Council houses to cut heating bills for tenants and reduce carbon emissions is set to increase by almost 60 per cent, according to council estimates.
The council expects to spend €83.1 million to retrofit the remaining 2,690 homes from its stock of 12,000 council houses, a cost of almost €31,000 per home.
The sum represents a substantial hike on its most recent energy upgrade programme, which has seen it retrofit 927 homes since 2018 at a cost of approximately €18 million or just over €19,000 per home.
However, the council said the work, while costly, had the potential to save tenants upwards of €800 a year in the face of rising fuel costs.
The council has completed a range of retrofitting and upgrade measures on almost 9,000 houses, bringing their building energy rating (BER) to an average of C3.
"Some of our old stock was down at F and G ratings," the lowest energy ratings in the BER scale, said senior executive engineer Shane Hawkshaw. "At that BER you can pump in as much heat as you like, but it's going to leave as quick. You might as well have a fire lighting and the front door wide open."
Most of the homes, a total of 8,057, have been upgraded with cavity wall insulation; attic, tanks and pipes insulation; roof and wall ventilation; draught-proofing; and cylinder lagging jackets.
However, in the more recent phase of the programme, the 927 homes have had external insulation, installation of heat pumps where possible, and new doors and windows to replace single glazing. This is in addition to internal insulation, draught-proofing and ventilation work.
Phase one of the programme concentrated on the council’s stock of housing from the latter decades of the 20th century, constructed with cavity walls which could be filled with insulation. The second phase involves the council’s older housing, generally dating from the 1930s to the 1960s, which were built with solid or hollow block walls, and require external insulation.
The first phase, which ended in 2018, cost €16 million, or less than €2,000 per home.
“Pumping cavities is a lot easier than external insulation, which is a lot more time-consuming and costly,” Mr Hawkshaw said. “You can pump a cavity house for less than €1,000 but when you’re externally insulating you are up around €15,000-€17,000.”
With the additional measures, including heat pumps or new boilers where applicable, and door and window replacement to some houses, the cost differences between both phases are considerable. “The costs are multiples of what they would have been in phase one, but it’s a far more significant upgrade.”
Retrofitting the remaining 2,700 houses, with similar systems to the 927 homes, will cost even more, Mr Hawkshaw said, with current projections of just over €83 million. While a significant element of this is down to rising construction costs, the council is also seeking to achieve the highest possible BER ratings.
“We will be targeting B2 and better going forward.”