NCC 2016 Volume Two
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ACT 7.1.2 Heating and Cooling Loads

ACT 7.1.2 Heating and Cooling Loads

(a)

Subject to (b) to (e), 3.12.0(a)(i) may apply to—

(i)

a whole dwelling as added to or as extended; or

(ii)

a house-like addition or extension as if 3.12.0.1 expressly indicated it applied to a large part of a building and as if the rating scheme and protocol mentioned in 3.12.0.1 applied to rating large additions or extensions to buildings rather than rating a whole building.

(b)

For (a)(ii), an addition or extension is not house-like unless—

(i)

it has a contiguous floor area of at least 100 m2 including any contiguous existing floor area up to no more than 50 m2 of the unaltered part of the building, that needs to be incorporated into the rating to minimise inaccuracy due to the effect of nearby elements of the unaltered parts; and

(ii)

it has at least 1 kitchen within the floor area mentioned in (i); and

(iii)

the floor area mentioned in (i) is isolated from other buildings and from the remainder of the unaltered part of the building by a draft-proof barrier such as walls, floor, ceiling and a draft-sealed door, all of which comply with 3.12.3.

(c)

If (a)(ii) is applied, the following must be included as part of determining the rating mentioned in (a)(ii)—

(i)

the relevant properties of any existing and unaltered roof, internal wall, or external wall that is taken as being part of the thermal envelope of the contiguous floor area of the addition or extension; and

(ii)

the remainder of the unaltered part of the building must be taken as a separate building adjoining the addition or extension, if it adjoins the part of the building being rated.

(d)

ACT 7.1.2 does not apply if compliance with it would result in a building (or part thereof), as extended or altered, having its energy efficiency reduced below—

(i)

the relevant statutory minimum, which is the minimum energy efficiency requirement, if any, that all or part of the building, respectively, was required to achieve when constructed or altered; or

(ii)

for a building that has not been altered or extended, the current energy efficiency of the building, which is the lesser of its energy efficiency determined using the factors Part 3.12 covers, or the energy efficiency it would be required to achieve under Part 3.12 if it was to be built; or

(iii)

for the following parts of a building—an unaltered, unextended, altered, or extended part—the energy efficiency for the part as per (ii) as if (ii) applied to the part.

Example for ACT 7.1.2(d)

Example for ACT 7.1.2(d):

A house constructed in 1980 was not required to be energy efficient. However, recently R4.0 bulk thermal insulation batts were installed in the roof space. Part 3.12 covers thermal insulation performance of roofs. ACT 7.1.2 does not apply to removing the bulk thermal insulation for use in an extension to the house. The house was extended in 2008 (the first extension). The first extension was required to comply with BCA 2008. A proposed second extension will shade northerly glazing in the first extension, bringing the first extension out of compliance with BCA 2008. Therefore, ACT 7.1.2 does not apply to shading the window without offsetting the detrimental effect that shading would have to the first extension’s energy efficiency even though the first extension does not comply with the requirements of current Part 3.12.

(e)

Dispensations in an ACT building legislation, however described, that may allow existing elements to not comply with the BCA under a deemed-to-satisfy method must not be applied to an energy efficiency rating under 3.12.0.1 or ACT 7.1.2. All relevant existing elements must be assessed in respect of their actual performance without dispensation.

Explanatory information

Explanatory information:

An alternative option to the EER provisions option is to make the relevant building elements comply with the respective energy efficiency provisions. That alternative option is referred to as the "elemental provisions". Elemental provisions are set out at 3.12.0(a)(ii) and ACT 7.1.3 to ACT 7.1.5.

Explanatory information

Explanatory information:

The energy rating scheme and protocol mentioned in 3.12.0.1 are intended to only apply to whole houses, not to only an addition or extension to a house, nor to part of a house that is less than the entire thermal envelope of the house. However, they can apply to attached houses to assess one or other attached house separately. Thus, they can produce reasonably reliable information about an extension to a house if the extension is comparable to adding an additional house to the existing house to form 2 attached houses.

If only an addition or extension to a house is rated, the rating is not necessarily a reflection of the house’s overall rating. Although area correction factors are included in relevant energy rating software, the accuracy of ratings can decrease with reduced size and number of rooms rated. Therefore, ACT 7.1.2 limits use of a rating to large additions or extensions.

As the energy rating scheme mentioned in 3.12.0.1 is intended to apply to a whole building, an assessment in regulatory mode must include a kitchen zone. In order to avoid the pretence of applying false heating and cooling loads to a zone, ACT 7.1.2 is limited to house additions or extensions containing a kitchen in the rated area. This can include an existing or new kitchen area.

ACT 7.1.2 permits small parts of an existing house to be incorporated into the addition or extension, to take account of draft-proof barriers that are not located at the interface between the existing house and the addition or extension. The construction details of any existing part incorporated into an addition or extension for rating purposes must not be assessed as having the same relevant details as the remainder of the addition or extension unless they are actually the same in both. For example, if the existing part is bounded by an internal wall with no bulk thermal insulation added, that wall must not be assessed as having the same properties as the remainder of the insulated bounding walls, unless they actually have the same relevant properties, (see Figure ACT 7.1.1).

Figure ACT 7.1.1

Diagram a. Addition not incorporating floor area from existing dwelling

v2_ACTFig711eg1_2015.svg
Note: Plan showing compliance with certain requirements of ACT 7.1.2(a)(ii) and (b), without incorporating floor area of an existing dwelling into the relevant floor area of an addition or extension to the dwelling. This is relevant where house energy efficiency rating software is used to demonstrate compliance.

Figure ACT 7.1.1

Diagram b. Addition incorporating floor area from existing dwelling

v2_ACTFig711eg2_2015.svg
Note: Plan showing compliance with certain requirements of ACT 7.1.2(a)(ii) and (b), incorporating a small amount of floor area of an existing dwelling into the relevant floor area of an addition or extension to the dwelling. This is relevant where house energy efficiency rating software is used to demonstrate compliance.