Section J outlines the Energy Efficiency Provisions of the NCC 2019 – Vol 1, with JP1 stating the requirements which a Performance Solution or Deemed-to-Satisfy Solution must meet. More specifically, JP1 states that a building, including its services, must-have features that facilitate the efficient use of energy appropriate to the following:
(a) the function and use of the building; and
(b) the level of human comfort required for the building use;
(c) solar radiation being—
(i) utilised for heating;
(ii) controlled to minimise energy for cooling;
(d) the energy source of the services;
(e) the sealing of the building envelope against air leakage;
(f) for a conditioned space, achieving an hourly regulated energy consumption, averaged over the annual hours of operation, of not more than—
(i) for a Class 6 building, 80 kJ/m2.hr;
(ii) for a Class 5, 7b, 8 or 9a building other than a ward area, or a Class 9b school, 43 kJ/m2.hr;
(iii) for all other building classifications, other than a sole-occupancy unit of a Class 2 building or a Class 4 part of a building, 15 kJ/ m2.hr
The NCC energy efficiency requirements are now underscored by a requirement to also ensure that human comfort (b) is met. In other words, whether meeting the Performance Requirements via a Performance Solution or Deemed-to-Satisfy Solution, both are deemed to ensure human comfort. Therefore, particularly in the case of glazing, much higher performance will need to be specified and met as a result.
In 2019, the stringency of commercial buildings has increased significantly, when compared to the last update to the NCC in 2016. Based on cost-benefit assessments, a 35% improvement in energy efficiency is stated to be deliverable through these changes with a cost-neutral impact on the market. While an incredibly ambitious target, such changes are subject to numerous questions of accuracy and unlikely in real terms.
Of the areas subject to increased stringency, the building envelope has seen the most onerous and challenging changes to how we design and construct buildings. Adopting a ‘fabric first’ approach, the thermal transmittance of roof, floors, walls and glazing systems have all seen new performance requirements, methodologies and metrics, making for a challenging transition from 2016 to 2019 compliance years.