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G-rated Meath bungalow aims for A rating — without renewables
Energy consultant Cillian Donoghue of BERCerts.ie is currently undertaking a retrofit project that will transform a neglected G-rated bungalow in Co Meath into an A-rated dwelling, using a fabric-first approach and without the use of renewable energy.
This article was originally published in issue 25 of Passive House Plus magazine. Want immediate access to all back issues and exclusive extra content? Click here to subscribe for as little as €10, or click here to receive the next issue free of charge
“Newly built homes typically meet compliance through renewables placed in the fabric, rather than the fabric itself. So an A-rated home is really a B-rated home, with renewables added,” Donoghue said.
“In 10 or 15 years time, many of our newly built homes — which all comply with buildings regulations now— may start needing to replace their heating systems, which may be defunct or out of warranty.
“Let’s say we all go out and install a 400% efficient heat pump then. All of the A3 houses that rely on renewables now will still have an A3 rating, whereas my ‘dumb’ building will get an A1. While a smart building or home is full of expensive ‘bling’, a dumb building is efficient by itself, or by its envelope.”
He continued: “While renewable energy is both positive and necessary, it should be considered lastly, and this concept seems to be lost on many. Because of this, too many new homes are over specifying renewable systems.”
“The sizing of a heat pump should only be considered once the envelope has been specified properly. In the field this seems not to be the case as it is based purely on size of the dwelling. My bungalow would have a vastly oversized system if I allowed a heat pump to be sized for it based purely on floor area or volume.”
Donoghue’s retrofit in Navan will include ground floor excavation and insulation, internal and cavity wall insulation, removal of chimneys and flues, and remodelling of the internal layout for solar gain. It will also include demand controlled ventilation and a target airtightness of 1m3/hr/m2 at 50 Pa. Careful detailing at junctions and other thermal bridges has been crucial to getting the house up to an A-rating, he said.
BERCerts.ie is a comprehensive energy consultancy that offers BER certs, airtightness testing, sound testing, energy audits, assigned certification and thermal imaging, as well expert advice and consultancy on Parts L, E (sound) and F (ventilation) of the building regulations, and on nZEB compliance.
