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ZEB Summit

Recovering heat from shower water and 3D printed homes: the future of house building in Ireland

A new conference aims to explore sustainable building in Ireland.

PLANT-BASED INSULATION, technology to recover the heat from shower waste waster, and 3D-printed homes are some of the innovations being explored as the EU moves to tackle emissions in its buildings.

A conference being held in Dublin later this month – the Zero Emissions Buildings (ZEB) Summit – aims to discuss and explore the ways to make old and new buildings in Ireland more environmentally sustainable.

According to estimates, over a third of all of the EU’s planet-warming greenhouse gas (GHG) emissions come from buildings, many of which are old, poorly insulated and heated and powered by fossil fuels.

Under its international commitments, the EU aims to be fully climate-neutral by 2050 - an economy with net-zero greenhouse gas emissions. This will require large-scale changes to almost every sector of society, many of which are already underway. 

For buildings, the EU has set two key targets. The first is to bring all older public and private buildings across the continent up to a proper environmental standard through a massive retrofitting programme (at a potential cost of €1 trillion).

In Ireland, the National Retrofit Plan aims to support the retrofitting of the equivalent of 500,000 homes by 2030, in order to bring them to a suitable standard. Progress has been slow however, with just under 48,000 homes supported last year, though this is a significant increase on 2022.  

The second major EU target is to ensure that all new builds on the continent are zero-emission buildings (ZEBs) by 2030. Essentially, ZEBs are buildings that produce the same amount of energy per year that they use.

It will fall to individual countries to put in place the laws and regulations to meet these targets. In Ireland, a number of innovations and avenues are being explored at industry level in order to make building more sustainable.

“Buildings in the future are not going to be consumers of energy but prosumers of energy,” said Tomás O’Leary, the managing director of Irish architecture firm Mosart. 

So a home in the future will be like a mini power plant. And the idea of those mini power plants is they should be brought to such an efficient level that they start to even out the energy consumption of the old buildings.

MosArt specialises in designing passive housing: buildings that meet very high environmental and sustainability standards.

The firm is also behind the upcoming ZEB Summit, which it is arranging in partnership with a number of groups, including Dún Laoghire Rathdown County Council.

DLRCC is currently building 597 new social and affordable homes at Shanganagh in Shankill. The scheme is supported by the Land Development Agency (LDA) and when completed will be one of the largest passive housing social schemes in Europe.

O’Leary says he designed the first passive house in the English speaking world in Wicklow in 2004, and since then he’s watched as buildings that meet a high environmental standard have become “a nice to have to a need to have”.

ZEB Summit aims to explore the shifting landscape of sustainable construction, with talks and panel discussions on a variety of different topics centred around sustainable housing construction and retrofitting programmes.

Among these, will be the use of 3D printing in home building, the use of plant-based insulation to lower emissions, and methods to recover the heat from drain water.

“Right now, every time you take a shower, all that heat and energy goes into the sewer and is completely lost,” said O’Leary.

“It’s as bad as using a plastic bottle just one time. It’s almost like single use energy. 

But in the future every house will have a very simple device that can recapture about 50-60% of the heat of the water that is going out into the sewer.

Up for discussion will also be how to manage and reduce the “embodied carbon” of buildings, that is the the greenhouse gas emissions arising from the manufacturing, transportation, installation, maintenance, and disposal of building materials.

EU changes

The EU is in the process of passing a new Energy Performance of Buildings Directive (EPBD) which will enshrine its new building targets into law, and it will then fall to each individual state to implement measures to achieve them.

The EPBD was agreed in principal in December last year, but it still needs to be voted on in the EU Parliament. That vote is due to take place later this month but work is already underway to start adapting home building for the future.

“We have achieved something remarkable… created a blueprint for the world to decarbonise its building stock,” Green Party MEP Ciarán Cuffe – who was the lead negotiator of the deal – said in December.

With this plan, we add an essential pillar to the EU’s decarbonisation plans  and begin the long journey towards reducing 36% of Europe’s CO2 emissions.

Climate scepticism

While the EU pushes ahead with its Green Deal and aims to decarbonise its economy, there is growing discontent from different sectors of society. 

In countries across the union, there has been a reaction against the implementation of green policies. The recent tractor protests by farmers’ groups are one indication of this.

Some experts are predicting that the upcoming European Parliament elections will see a shift towards parties and MEPs hostile to an environmental agenda.

What this means for the future of homebuilding in Europe and Ireland remains to be seen, however O’Leary of MosArt says that the drive towards sustainability is not solely being pushed by EU regulations, but by customers’ preference and, crucially, international finance.

“It’s interesting, it’s almost like the building regulations are not driving performance anymore, it’s the global drive for sustainability.

Essentially, if you don’t have the know how to deliver high performance homes you’re going to get left on the roadside.

Zeb Summit takes place on 21-21 February