BC Update: No.95 - Building Code clause H1 energy efficiency amendments

30 January 2009: From 1 February 2009, new Building Code (NZBC) provisions for hot water and HVAC systems come into force.

The Department provides the following guidance to help designers and building consent authorities (BCA) interpret the new provisions relating to hot water and HVAC. BCAs, when issuing building consents, will need to consider the provisions on a case-by-case basis. Copies of the new NZBC clause H1 are available at: www.dbh.govt.nz/energy-efficiency.

Hot water energy efficiency provisions of the Building Code now include a new requirement for systems to “be constructed to facilitate the efficient use of hot water” (new NZBC clause H1.3.4(c)). This new provision only applies to buildings that are classified as housing (refer NZBC clause A1 for definitions). The existing Acceptable Solution for hot water energy efficiency, H1/AS1 5.0, states that “hot water systems complying with NZS 4305 satisfy the requirements of NZBC H1.3.4”. This Acceptable Solution remains in force for H1.3.4(a) and (b). However, in the absence of a new Acceptable Solution that expressly includes H1.3.4(c), NZS 4305:1996 can be used to interpret H1.3.4(c) as well.

Heating, ventilation and air conditioning (HVAC) systems are no longer excluded from NZBC Clause H1 after 31 January 2009, and a new performance (H1.3.6) is added as follows,

H1.3.6 HVAC systems must be located, constructed, and installed to –

(a) limit energy use, consistent with the intended use of space; and
(b) enable them to be maintained to ensure their use of energy remains limited, consistent with the intended use of space.

H1.3.6 will only apply to buildings that are classified as commercial (refer NZBC clause A1 for definitions).

There is currently no acceptable solution or verification method for the new NZBC clause H1.3.6. Very little comment was received on the latest version of a proposed Acceptable Solution for HVAC released for public submission in October 2008. The Department has therefore decided to publish the main elements of this document as guidance rather than to publish a Compliance Document. This will allow designers and Building Consent Authorities more flexibility and allow more time for further consideration before any Compliance Document is completed. This guidance document Guidelines for energy efficient HVAC plant is available from the Department (www.dbh.govt.nz/energy-efficiency) to assist BCAs in making decisions on whether the new HVAC provisions have been met. This is not a compliance document and the decision of whether a design complies with these new provisions is for the BCA to make.

The Department will continue to work with the sector to improve guidance/compliance documentation and enable better energy efficiency outcomes. Submissions on proposals for amendments to the H1 Compliance Document will be sought later in the year.