NZEB - Nearly Zero Energy Buildings in Ireland

Today we've been at the nZEB-15 National Retrofit Conference at Dublin Institute of Technology listening to the latest research, developments and education in this energy retrofit technology for Irish buildings.

Introduction video - Near Zero Energy Buildings

Some Information on Nearly Zero Energy Buildings standards in Ireland:

From January, 1st 2019 every new public building will have to be designed to nearly zero energy building standards. Also, all other new buildings will have to comply with the new nearly zero energy buildings standards from January, 1st 2021. This arises from the Recast European Performance of Buildings Directive 2010/30/EU.

For a typical dwelling this will equate to 45 kWh/m2/annum and an Energy Performance Coefficient (EPC) and Carbon Performance Coefficient (CPC) of 0.302 and 0.305 in accordance with the common general framework set out in Annex I of Directive 2010/31/EU on the energy performance of buildings (Recast). This takes account of the energy load for space heating, water heating, fixed lighting and ventilation. A very significant proportion of which will be covered from renewable energy sources produced on-site or nearby. (Ref: Towards Nearly Zero Energy Buildings in Ireland – Planning for 2020 and beyond. 

 The proposed improvement from current building  standards  to  an intermediate and final NZEB target for buildings other than dwellings are:

Targets will be further refined when developing new the technical performance standard TGD L – Buildings other than Dwellings. (Source: Towards NZEB in Ireland- Planning for 2020 and beyond)

Energy Performance of Buildings Directive (EPBD)

The EU Energy Performance of Buildings Directive (EPBD - 2002/91/EC) is the main European legislative instrument for improving the energy efficiency of Europe's building stock. Under the Directive, the following obligations were introduced in all Member States:

• A methodology to calculate and rate the integrated energy performance of buildings
• A system of energy certification for new and existing buildings, with display requirements for public buildings
• Regular inspections of heating and air-conditioning systems
• Minimum energy performance standards for new buildings and for existing buildings that undergo major renovation with a useful floor area over 1000m2

The EU Energy Performance of Buildings Directive (EPBD) was transposed into Irish Law from 2006 onwards.

From 2013, the EPBD was superseded by the Recast EPBD and S.I. No 666 of 2006 was superseded by S.I. 243 of 2012.  See more at: http://www.seai.ie/Your_Building/EPBD

Changes in the Building Regulations in Ireland

Building Regulations were first introduced in Ireland in 1976 in Draft form and revised draft Regulations were introduced in 1981. The Building Regulations were formally revised in 1991, 1997, 2002, 2005, 2008 and 2011.

There have been significant step changes in the Irish Building Regulations since 2005. Technical Guidance Document Part L (TGD L), of the 2008 Regulations required a 40% reduction in primary energy use compared to a reference dwelling specified in the TGD Part L 2005 Regulations. TGD L of the 2011 Regulations require a 60% reduction in the primary energy us. The gradual improvements leading to NZEB standards for dwellings are summarised in the table below. 

*These energy values are for a typical two storey semi-detached house.

Information from NZEB Open Doors Ireland.

Passive House Principles Simply Explained:

With Dun Laoghaire Rathdown and Dublin City Councils set to make Passive House standards mandatory for new buildings in their forthcoming Development Plans - 

“The time has come in Ireland for passive house standards to move from the margins to the mainstream, for building policy and its energy efficiency to become more active by becoming more passive... " - Pat Cox

Passive House or "Passivhaus" buildings provide a high level of occupant comfort while using very little energy for heating and cooling. They are built with meticulous attention to detail and rigorous design and construction according to principles developed by the Passivhaus Institute in Germany, and can be certified through an exacting quality assurance process.

The new-build Passivhaus Standard requires:

• a maximum space heating and cooling demand of less than 15 kWh/m2.year or a maximum heating and cooling load of 10W/m2
• a maximum total primary energy demand of 120 kWh/m2/year
• an air change rate of no more than 0.6 air changes per hour @ 50 Pa

The Passivhaus refurbishment standard, EnerPHit, requires:

• a maximum space heating and cooling demand of less than 25 kWh/m2.year or a maximum heating and cooling load of 10W/m2
• a maximum total primary energy demand of 120 kWh/m2/year + heat load factor
• an air change rate of no more than 1.0 air changes per hour @ 50 Pa

To achieve the Passivhaus Standard in the Ireland typically involves:

• very high levels of insulation
• extremely high performance windows with insulated frames
• airtight building fabric
• ‘thermal bridge free’ construction
• a mechanical ventilation system with highly efficient heat recovery

Just bear in mind though:

"It is far more difficult to be simple than to be complicated; far more difficult to sacrifice skill and easy execution in the proper place, than to expand both indiscriminately".  John Ruskin.

Passive House Ireland - Facebook

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Passive House Simply Illustrated

We came across these wonderfully simple illustrations of the principles of Passive House design (Passive Haus) and thought they were well worth sharing.  They are by a U.S. firm, Albert, Righter and Tittman Architects. 

 The illustrations help make the case that green building in the new millennium should be about simplicity: weaving together and maximizing simple technologies rather than relying on fancy gizmos and complex systems.

The first image shows the evolution in building technology over the centuries, from wood-heated homes in the 19th century, to a complex jumble of building systems in 20th century homes, to the promise of simplicity presented by today’s Passive House standard:

It’s all about the envelope.  A central principle of Passive House design is to reduce heat loss by superinsulating homes, creating airtight building envelopes, and eliminating thermal bridges (elements or penetrations that allow heat or cold to leak through the fabric):

With a carefully-designed and executed building envelope in place, almost all the heating needs of a Passive House can be met by body heat, heat from lights and appliances, and solar gain:

The control of these solar gains can be easily regulated though a combination of well considered siting (along the east-west axis), shade-providing overhangs for the highest sun of the summer months, and the careful placement of high-performance windows.  All that’s left is to include heat-recovering mechanical ventilation, a simple system that exhausts spent air and brings in fresh air, all the while capturing and retaining the thermal energy of that exhausted air:

The end result is a comfortable, normal-looking home that saves 75-90% of the energy consumed by a conventional home.

Hofler Architects - Monkstown, Dun Laoghaire, Co. Dublin