J1P2 Performance Requirements

J1P2 Thermal Performance of Sole-Occupancy Units in Class 2 and Class 4 Buildings sets limits for heating loads, cooling loads and thermal loads, as per Specification 44. Specifically, these are set within S44C2, S44C3 and S44C4, where the limits of each Class 2 (sole-occupancy unit (SOU)) are established and adjusted for the total area of habitable space.

Specification 44 - S44C2 and S44C3 - must be used to calculate the heating and cooling load limit for each SOU in order to verify J1V5(1)(a) and/or J1V5(1)(b).

What is S44C2 - Heating load limit?

S44C2 sets the heating load limit of a space (MJ/m2.annum). It is equal to the greater of:

a) 4; and

b) $((0.0044×HDH)−5.9)×FH$, where—

$HDH$= the total annual heating degree hours of the building location; and

$FH$= the area adjustment factor for the heating load limit, determined in accordance with Table S44C2.

Table S44C2 outlines the area adjustment factor (FH) based on the total area of habitable rooms (AH). For rooms with an area of 50 m² or less, the adjustment factor is set at 1.37.

When the area exceeds 50 m² but is less than or equal to 350 m², the factor is determined by the quadratic formula: ( 5.11 × 1 0 − 6 ) 𝐴 𝐻 2 − ( 3.82 × 1 0 − 3 ) 𝐴 𝐻 + 1.55.

For rooms with an area greater than 350 m², the adjustment factor is fixed at 0.84. This table helps in adjusting calculations for energy efficiency assessments based on the size of the habitable room area.

Table S44C2

Total area of habitable rooms (AH)	Area adjustment factor (FH)
≤ 50 m2	1.37
> 50 m2 to ≤ 350 m2	$(5.11×10−6)AH2−(3.82×10−3)AH+1.55$
> 350 m2	0.84

What is S44C3 - Cooling load limit?

S44C3 sets the cooling load limit of a space (MJ/m2.annum) in accordance with the following formula:

$CLL=(5.4+0.00617×(CDH+1.85DGH))×FC$

$CLL$= the cooling load limit (MJ/m2.annum); and

$CDH$= the total annual cooling degree hours of the building location; and

$DGH$= the total annual dehumidification gram hours of the building location; and

$FC$ = the area adjustment factor for the cooling load limit, determined in accordance with Table S44C3.

Table S44C3 details the area adjustment factor (FC) for different ranges of the total area of habitable rooms (AH). For areas up to 50 m², the adjustment factor is set at 1.34.

For areas greater than 50 m² but not exceeding 200 m², the factor is calculated using the formula: ( 1.29 × 1 0 − 5 ) 𝐴 𝐻 2 − ( 5.55 × 1 0 − 3 ) 𝐴 𝐻 + 1.58. For areas between 200 m² and 1000 m², the formula ( 3.76 × 1 0 − 7 ) 𝐴 𝐻 2 − ( 7.82 × 1 0 − 4 ) 𝐴 𝐻 + 1.12 is used.

Lastly, for areas exceeding 1000 m², the adjustment factor is fixed at 0.71. This structured approach allows for precise adjustments in energy efficiency assessments based on the size of the habitable room area.

Table S44C3

Total Area of Habitable Rooms (AH)	Area Adjustment Factor (FC)
≤ 50 m²	1.34
> 50 m² and ≤ 200 m²	(1.29 × 10⁻⁵) AH² - (5.55 × 10⁻³) AH + 1.58
> 200 m² and ≤ 1000 m²	(3.76 × 10⁻⁷) AH² - (7.82 × 10⁻⁴) AH + 1.12
> 1000 m²	0.71

What is S44C4 - Thermal energy load limit?

S44C4 sets the thermal energy load limit of a space (MJ/m2.annum), calculated in accordance with the following formula:

TLL = 19.3 HLL + 22.6 CLL − 8.4 / Tr + 10.74 − 15

TLL represents the thermal energy load limit.

HLL represents the heating load limit.

CLL represents the cooling load limit.

Tr represents the annual average daily outdoor temperature range.

S44C4 calculates the thermal energy load limit (TLL) based on the heating load limit (HLL), cooling load limit (CLL), and the annual average daily outdoor temperature range (Tr).

It combines these factors using specific coefficients and constants to determine the maximum thermal energy load that a system or building can accommodate, considering both heating and cooling needs along with outdoor temperature variations.

S44C4 - Thermal energy load is not required for J1V5. It is only required if an independent Performance Solution is being undertaken to meet the Performance Requirement J1P2.