Something old, something new: building greener homes in Northern Ireland


Sustainability and energy efficient properties are to the fore, but there’s still much to be done as experts explain

Research, carried out by Ulster University (through Professor Martin Haran & Forum for Better Housing Market NI) found that 60% of homes in Northern Ireland will need improving in order to meet net zero targets — roughly 50,000 buildings per year to be upgraded to meet 2050 targets.

We are a long way off meeting this target, says architect company Marshall McCann, which says that Northern Ireland has the worst housing stock in the UK and Ireland.

“We are also the only region in UK and Ireland not to have any grants or incentives to upgrade the thermal efficiency of our homes. Ireland currently has grants up to €50,000 for all houses built pre-2011. These grants are not means tested,” explains Roisin McCann from the company.

“The average EPC [energy performance certificate] rating of houses in Northern Ireland is Band D (SAP rating 57), with over 75% of housing worse than band C.

“Research also shows that houses in the most disadvantaged areas of Northern Ireland score the lowest EPC ratings. Detached houses in rural areas score the worst, with apartments performing the best.”

The Forum’s report, New Foundations: The route to low carbon homes, sets out recommendations to support the process of decarbonisation across our housing sector, which currently contributes to 14% of the locality’s total greenhouse emissions, much higher than counterparts in Great Britain.

The report recommends the development of a single policy vision focusing on incentivising developers, construction firms and homeowners to create more energy-efficient homes.

“From my viewpoint, the new build sector will take care of itself in that regulations invariably will mean that we will have to get to a higher build standard,” says Professor Martin Haran, who led the research.

“Building regulations are already moving there so it’ll be a requirement for new developments to conform and comply with new building regulation specifications.”

Passive homes are becoming increasingly popular

At the rate older homes are being upgraded with better insulation and energy efficient heating, NI’s housing stock will not meet UK’s 2030 carbon reduction targets.

Professor Haran speaks of a need for a culture change and education for developers who may believe such decisions will add costs to their build.

“There’s increasing evidence from Europe or even from the Republic of Ireland that through innovative design, through creative material sourcing and procurement, that the actual costs of building net zero or passive house standards can almost be neutralised in many respects.

“The other thing that is if you’re building to a higher standard, does that invariably mean that the value of what you’re building is greater. And then it comes back to how do we value energy efficiency? How do we apply the energy efficiency features? Is that adding value to your property? So if you’re building to a higher standard, is the value of what you’re building more sought after in the market and are purchasers willing to pay more?”

The new build sector, he says, is not the most problematic — it’s the existing stock sector. Over 80% of houses in NI that will be in situ in 2050 have already been built, but there remains a hesitancy to undertake retrofitting.

“There’s a consensus and a feeling that somewhere down the line, governments are going to have to provide some form of grant funding or incentivisation to do this. As a result of that, people, even if they’re willing to do it, or thinking about doing it, or gaining knowledge and insight about what they want to do in terms of retrofit, aren’t willing to push the button, because why would you spend your own money [when] in a year’s time, two years’ time, three years’ time down the line, there may become a grant funding available,” says Professor Haran.

“And the reality is, we’re seeing funding initiatives in GB, so why would those not at some point be brought to NI.

“So, I suppose that creates a backdrop where there is a reluctance and a hesitancy even amongst those that are showing an appetite to do so, and probably have the financial capacity to do so, not actually pressing that button just yet.”

Finding retrofitting solutions — fabric-based interventions, low-carbon heating systems — and developing a more diverse range of incentive-based green mortgage products, was another suggestion made by the report. Existing houses need to become more sustainable, but according to the Forum’s report, retrofitting capacity needs to double if 2030 targets are to be met.

“There is a saying, ‘The most sustainable building is an existing building,’” says Roisin from Marshall McCann.

“This means that an existing building has carbon embodied within it; to knock down and build new is not a sustainable way, as that means we are using more carbon — the initial building was built, and carbon is used to demolish the house (and potentially ends up in landfill), then more carbon is used to build a new house.

“Sustainability is a very generic term. Retaining and upgrading a building is generally the most sustainable (i.e. least harm to the environment); but it does not necessarily mean your house will be as easy to heat as a new build. Embodied carbon and operational energy are two different strands of the sustainability agenda in construction; both of which play an important part.”

The Royal Institute of British Architects (RIBA) have set climate goals for 2030, an aid to move us towards net zero in 2050. These goals set out targets for the operational energy use of the house (how much energy it will take to operate the home to a healthy living standard), the amount of embodied carbon (i.e, how much energy has been put into the construction of the house.

Insulation is one of the principles of passive house design

With the recent cost of living crisis, the hike in energy prices, and the increased summer temperatures, people are more incentivised to build more sustainably.

That said, upgrading the energy efficiency of a house needs to be done carefully, and it may not be easy or cost effective. Though house specific, possibilities include the addition of insulation, achieving better airtightness to reduce air leakage and draughts while increasing ventilation.

“Careful thought and detailing is required; but for all our health, thermal comfort, and the reduction of operational energy, it is essential that our existing housing stock is upgraded,” says Roisin.

“Each house needs to be assessed individually, to understand its construction, and how best to make the house more thermally comfortable.”

As energy prices rise and climate awareness increases, there’s a move towards building to the Passive House standard, the fastest growing energy performance standard in the world.

Benefits for homeowners include healthy properties, thermally comfortable to live in, with low running costs.

There are also studies showing that Passive Houses are more healthy to live in; especially for those with respiratory or allergic tendencies, due to the high quality of light and air within the home. Mould growth, condensation, and toxic gases in the home are reduced.

As Passive House architects, Marshall McCann adhere to a fabric first approach: get the fabric (construction) of your house first, reduce carbon emissions and running energy costs before adding technology to produce energy.

The five principles of a Passive House together mean consumers reduce heating demand to a low level, what Passive House Association of Ireland’s chairperson Barry McCarron calls ‘the secret sauce.’

They are the insulation of floor, wall and roof, thermal bridging (attending to weak points such as junctions which may allow heat to pass through more easily), triple glazed windows, then making the building airtight to mechanically ventilate it.

“But what has happened before is that the interaction of these last two principles got confused,” says Barry over this debate within the construction industry.

“Sometimes, building regs are advocating increased air tightness, but then they’re also advocating natural ventilation. The two are incompatible.

“The two are a contradiction; you can’t make it airtight and expect it to be naturally ventilated.”

Barry is also South West College’s Research and Development Coordinator for the Centre for Renewable Energy and Sustainable Technologies.

In 2021, the college’s Erne Campus became the first educational building worldwide to achieve the highest international standard in environment construction — Passive House Premium.

Across Northern Ireland, moves are being made to adopt Passive House design principles, including in developer Fraser Millar’s Lancaster Park development in south Belfast. The company aims that its homes consume between 75-90% less heating energy than a conventional home.

“If I asked my students what percentage of all emissions globally comes from aviation, most people would give you an answer of 10%, 20%,” says Barry.

“The figure is actually less than 3%. Buildings is actually 40% and the single biggest problem facing the world, it’s even higher than agriculture, it’s higher than transport.

“Buildings really are the low hanging fruit that should be tackled in this debate, not culling the herd.

“I think all those things would probably have to happen to get to net zero, yes.

“But if you were to start at the start, buildings are an easy win.”


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