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All New Homes Will Be Nearly Zero Energy Buildings (NZEB)

Amendments to Part L of the Building Regulations (relating to the conservation of fuel and energy in dwellings) will come into effect on 01 November 2019.

All new homes will have a typical Building Energy Rating (BER) of A2 and will be 70% more energy efficient and emit 70% less carbon dioxide than 2005 performance levels.

What is a Nearly-Zero Energy Building (NZEB)?

‘Nearly zero-energy building’ means a building that has a very high energy performance. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby.

Are there any exceptions to the new regulations?

Yes, but only if planning approval or permission has been applied for on or before 31st October 2019 and substantial work has been completed by 31st October 2020.

“Substantial work has been completed” means that the structure of the external walls of the dwelling has been erected.

 What are the key changes to TGD L Dwellings 2019?

  • MPEPC (Maximum Permitted Energy Performance Coefficient)=0.30, in order to achieve the acceptable primary energy consumption rate.
  • MPCPC (Maximum Permitted Carbon Performance Coefficient)=0.35, to demonstrate that an acceptable CO2 emission rate has been achieved.
  • Where a dwelling undergoes major renovation, the energy performance of the whole dwelling should be improved to Cost Optimal level insofar as this is technically, functionally and economically feasible.
  • Introduction of a Renewable Energy Ratio (RER) of 20%.
  • Reduction of air permeability backstop from 7m3 /hr/m2 to 5m3 /hr/m2.
  • Table 1- Reduction of wall and floor backstop U-Value from 0.21W/m2K to 0.18 W/m2K.
  • Table 1- Reduction of window backstop U-Value from 1.6 W/m2K to 1.4 W/m2K.
  • Inclusion of guidance to avoid overheating in dwellings.
  • Par 1.3.2.4 – removal of variation of U-Value with percentage glazing.
  • Introduction of calculation of Ru value for corridors in apartments.

How can compliance be achieved?

The correct specifications need to be prepared by your Architect to your specific project. Compliance is then demonstrated using the DEAP (Dwelling Energy Assessment Procedure) software.

Below is an example prepared by the Department of Housing, Planning and Local Government for a semi-detached dwelling with 126 sq.m. and with heat pump for space heating and continuous mechanical extract ventilation.

NZEB example specification
Semi-detached dwelling with 126 sq.m. and with heat pump for space heating and continuous mechanical extract ventilation

A nearly zero energy buildings (NZEB) future – Minister English reminds construction sector to be prepared for new building regulations on energy efficiency

What’s All the Fuss About the Revised Energy Performance of Buildings Directive

Overview of Key Changes to TGD L – Dwellings 2019

Minimum BER Rating for New Houses Built in 2019

 

We are quickly approaching the introduction of Nearly-Zero Energy Buildings (nZEB) standard and once again we are asked to improve the energy performance of buildings.

 

What is a Nearly-Zero Energy Building (nZEB)?

‘Nearly zero-energy building’ means a building that has a very high energy performance. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby.

When will the new regulations be introduced?

Article 9(1) of Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings requires that all new buildings:

– shall be nearly-zero energy buildings by 31 December 2020;

– occupied and owned by public authorities shall be nearly zero energy buildings after 31 December 2018

A full review of Part L of the Building Regulations is expected to be published very soon, this will include the nZEB standard.

What are the transitional arrangements?

This will be confirmed when the reviewed Part L of the Building Regulations is published.

The draft transitional arrangements required the standard to apply to all new dwellings commencing construction from 1st April 2019 (subject to transition).

Transitional arrangements (draft) will allow Part L-2011 Dwellings to be used when planning permission has been applied for prior to the application date of 1st April 2019 and substantial work * is completed by 31st March 2020.

*The structure of the external walls has been erected.

 

How will compliance with nZEB be demonstrated?

For domestic buildings, compliance will be demonstrated using the DEAP methodology. DEAP is currently being updated to account for NZEB.

For non-domestic buildings, compliance will be demonstrated using the NEAP methodology.

 

Is nZEB standard only for new houses?

No, the new standard applies to Domestic and Non Domestic Buildings.

It also applies to existing buildings (Domestic and Non Domestic) where major renovations take place.

Major Renovation’ means the renovation of a building where more than 25% of the surface area of the building envelope undergoes renovation.

For Existing Non Domestic Buildings this will require that the building is brought up to cost optimal level, which is defined in the building regulations as:

  • Upgrade Heating System more than 15 years’ old
  • Upgrade Cooling and Ventilation Systems more than 15 years’ old
  • Upgrade Lighting more than 15 years old.

For Existing Domestic Buildings, it is proposed that major renovation is typically activated where external wall is renovated. The cost optimal level is a primary energy performance of 125 kWh/m2/yr when calculated using DEAP or upgrade of roof insulation and heating system.

 

What are the BER requirements once nZEB standards are implemented?

This is currently out for public consultation, refer to Department of Housing, Planning and Local Government website for proposed changes to the regulations and DEAP methodology.

For all new builds, it is proposed that nZEB will be equivalent to a 25% improvement in energy performance on the 2011 Building Regulations.

This equates to an energy performance and carbon performance parameter that is 70% better than Ireland’s 2005 standard.

A new Nearly-Zero Energy Building (Dwelling) will typically correspond to an A2 Building Energy Rating (BER).

 

 

Will a new house be more expensive to build from 1st April 2019?

The impact on design and cost is expected to be relatively small.

The projected increase is 1.9% over current construction costs depending on the dwelling archetype and design specification applied.

 

 

Please Build Exactly as per Specifications

 

We always get nervous when the Contractor or the Client rings asking to change this or that. This would typically happen at construction stage and after we have spent long hours preparing construction drawings, specifications, etc. Many details are quite complex and it is not easy to change them from A to B in the hour. Furthermore, they are likely to involve extensive calculations to comply with Part L of the Building Regulations and possibly more research.

It would be easy enough to change the colour paint for a bedroom but changing a whole wall construction or even just the wall insulation is not that easy, it is time consuming and it kind of defeats the purpose of preparing pre-construction drawings.

Recently we found out on site that an existing wall was not as we had assumed in our drawings and calculations. We were prepared to review the specification and there were notes in our drawings that requested the Contractor to confirm the type of wall before proceeding with works. This was not a change requested by the client or contractor, it is just an example of what is involved when something changes. Between research, new drawings, calculations, etc there were about 10 hours extra to properly detail this variation. The image below shows one of the U-value calculations for just ONE wall. The client rarely gets to see all the work that is involved when things change on site.

WUFI-calculations2

 

In conclusion, unless there is a really good reason to change the specification, please think careful before you ask and please understand the implications not only for your Architect but also for the Assigned Certifier.

And even more important – please do not change the specifications without getting permission from the Architect/Contract Administrator!




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