Energy Efficiency, Computer Simulation and Building Certification

Certifiers (A1BS) are reporting some discrepancy in relation to Energy Efficiency compliance between computer simulation assessments and design details, on building application plan and specification. Currently any person, for example, who does a BERS course (becoming an accredited Simulator); can provide House Energy Rating (HER) simulation certificates.

Energy efficiency simulation practices, at this stage, do not fall under a specific license class. Therefore Building Certifiers will need to have sufficient awareness of energy efficiency issues (in the context of town planning schemes), when accepting simulation certificates (6 star ratings).

House Energy Rating certificates will be required at: the design stage (i.e. for Building Designers), the certification stage (i.e. for Building Certifiers), at point of sale/purchase (i.e. for Completed Building Inspectors), or for other condition reports (i.e. for Completed Building Inspectors). However, computer simulations can be manipulated for desirable outcomes (cheating). Input-criteria may be hypothetical, that is, not part of contractual documents.

HERS Simulators can refer to the Building Codes of Australia and may rely on tools such as point scoring tables or computer software programs, but will also be subject to inputs based on specialist judgement. Therefore HERS simulators will need to be knowledgeable on building regulation, design, building components and material, but Simulators should also be trained in energy efficiency theory, design and systems, to facilitate specialist judgement and competency.

Conclusions from random inspections by a major local government authority (in previous years) suggest that inspections are apparently not being conducted on energy efficiency provisions, indicating that up to 50% of completed dwellings (that were inspected) failed to comply. Further, Accredited Simulators and Building Certifiers may not be passing information, on compliance requirements, on to the Builders, i.e. a check-list of input criteria used to produce the simulation certificate.

The energy efficiency provisions are intended to be a first step in developing more effective energy standards to reduce greenhouse gas productions, reduce ongoing energy consumption and improve thermal comfort. The Provisions will apply in all local government areas throughout the State and in accordance with IPA section 3.1.3 (5), will override any similar provisions of a local governments planning scheme (Building Codes Queensland Newsflash issue 16.05.03, p. 2).

The objective of the BCA is to reduce Greenhouse Gas Emissions (GHGE) through efficient use of energy, based on thermal performance criteria. Verification (for climate zones 1 to 3) is based on annual energy load value, equivalent to a 6 star house energy rating. The new energy standards refer to building elements such as insulation, shading, glazing and ventilation. Part 2.6 (performance requirements) and Part 3.12 (deemed-to-satisfy) on energy provisions.

It is intended that energy provisions apply to extensions/alterations that create a separate definable room with separation walls, including the enclosing of spaces under a raised dwelling. The energy provisions apply to pre-built dwellings brought onto site and to alterations to compliant buildings. Building Code Queensland (BCQ) takes a commonsense approach to the relocation of existing buildings, where, if external cladding is not removed walls need not be upgraded with insulation, but accessible roof spaces should comply. Alterations extending rooms should comply, but compliance need not extend to the whole house. External shading should apply, but eave overhangs need not be extended in the process. However energy provisions are not intended to apply to extensions of existing rooms that are non compliant, nor are separate class 10 buildings applicable. Further applications to rising of non-compliant buildings are not compelled to comply. Applications for changes of building classifications, however, will call on full consideration of energy efficiency provisions (BCQ Newsflash issue 16.05.2003).

Computer simulation software, such as BERS, First Rate or NatHERS, should specify: building fabric, glazing and shading, air infiltration and ventilation, function and use of the building (zoning), with operating hours and casual loads, temperature settings and relevant built-environment and topographical features.

A local authority, for example, adopts new EE standards by assessing deemed-to satisfy provisions along with computer simulation to confirm equivalence and design compliance. Through the computer simulation process a check list is provided that can aid visual on-site inspection. Further, Builders are required to provide (on letter head) an affidavit that construction and installation processes were completed in accordance with approved plans and specifications that comply with energy standards.

� Building Codes Queensland , 2003, Energy Efficiency Provisions for Class 1 and 10 Buildings, Building Newsflash, May, pp. 1-4.
� Australian Greenhouse Office 2003, Energy Efficiency: Introductory Awareness Training, Chapter Four: Verification Methods, Australian Building Codes Board, May, pp. 1-36.
� Building Codes Queensland, 2003, Building Newsflash, issues: 25.07.03 31.10.03 03.11.03 – 07.11.03 – 14.11.03, Queensland Government.
� Australian Building Codes Board, 1996, Class 1 and Class 10 Buildings: Housing Provisions, volume 2, Building Code of Australia, CanPrint Communications Pty. Ltd