11.12.3 Building Design

Dúnta22 Nol, 2020, 09:00 - 12 Már, 2021, 17:00
​​​​​​11.12.3 Building design

The Urban Design Manual[1] sets out how sustainable energy considerations should be incorporated into all stages of the design process. 

The Building Regulations, Part L – Conservation of Fuel and Energy – set out the requirements for dwellings[2] and for buildings other than dwellings[3].   In order to ensure that the Building Regulations are fully taken into account in the design of any proposed dwelling, it will be a requirement that all planning applications be accompanied by a provisional BER cert stating that the proposed dwelling is in accordance with the current Technical Guidance Document L - Conservation of fuel and energy.


​​​​​​​ NZEB Building Regulations 2019 TGD -L

Since new building regulations have improved energy performance of homes over the past 10 years all new homes after 2016 are now A-rated homes providing warmth and comfort with very low energy demand. The integration of 20%  renewables is now typically achieved using 2-4 kW of solar PV with heating typically provided by Electric Heat pumps and electric car charging unit fitted in most homes.

It is expected that batteries will be soon integrated into most homes and that they will store energy for use in home using smart appliances and charging electric vehicles over the next decade.


​​​​​​​​​​​​​​ NZEB requirements for Non-Domestic Buildings

For new buildings

For all new builds, an equivalent to a 60% improvement in energy performance on the 2008 Building Regulations is required. This means an improved energy performance for the fabric, services and lighting specification. It also introduces a mandatory requirement for renewable sources. The renewable sources must in general provide 20% of the primary energy use, however there is flexibility where the building is more energy efficient than the regulations. This typically corresponds to an A3 Building Energy Rating.

For major renovation

For existing buildings under EPBD, major renovation is where “more than 25% of the surface area of the building envelope undergoes renovation”. 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.


​​​​​​​​​​​​​​ NZEB requirements for Domestic Buildings.

For new buildings

For all new builds, NZEB is equivalent to a 25% improvement in energy performance on the 2011 Building Regulations. A range of examples are shown in excel versions of the DEAP software available in the Domestic BER Resource page. Key changes to Part L for NZEB compliance include a Maximum Energy Performance Coefficient of 0.3, a Maximum Carbon Performance of 0.35 and a renewable Energy Ratio of 20%.

For major renovation

For existing buildings, major renovation is typically activated under the following circumstances, where the work affects greater than 25% surface area of the existing dwelling:

  • External Wall Renovation, external or internal insulation
  • External Wall & Window Renovation
  • External Wall & Roof Renovation
  • External Wall & Floor Renovation
  • New Extension

The cost-optimal level is a primary energy performance of less than 125 kWh/m2/yr (B2 BER) when calculated using DEAP or upgrade of ceiling insulation and heating system.


[1] Department of Environment, Community and Local Government, Urban Design Manual, A best practice guide 2009

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