G'day Guys,

I'm doing some preliminary calculations for a hypothetical build, based in climate zone 7 (Buninyong, VIC).

Based on the following numbers, and assuming a well sealed house, is a heat load of 3.57kw (based on 0c outside, 20c inside) correct? Or, do we make allowances for body heat, appliance heat, passive gain with North facing glazing etc etc? 4 people in the home.

Appreciate any feedback! Cheers

Notes:

30mm Foil board to all exterior walls, tightly taped to all penetrations

Impermeable membrane fitted inside the studs and ceiling, tightly sealed to all penetrations

Zehnder HRV for fresh air supply

48.75sqm total glazing. 41.95 = North, 2.80 = West, 4.0 = South, 0 = East. 450mm eave to whole home

Heat source = either in slab hydronic (decoupled from main slab with two pour system) driven by air source heat pumps, or split system to main space only

External Temp (degrees celsius) = 0

Internal Temp (degrees celsius) = 20

Ceiling height (m) = 2.7

Length of home (m) = 9.2

Width of home (m) = 22.3

Internal Floor area (sqm) = 172

Window area (sqm) = 48.75

Ceiling R Value =7 U = 0.14 kw loss = 0.49 (R7 Batts)

Slab R Value =2 U = 0.50 kw loss = 1.72 (375mm waffle pod, foil board insulation to all edge beams)

Wall R Value =5 U = 0.20 kw loss = 0.49 (R2.7 batts plus 30mm foil board to exterior)

Window U =0.9 kw loss = 0.88 (Note: triple glazed PVC, all fixed windows, two sliding doors to main space)

Total Load (kw) 3.57

Allowable under P/House (kw) 1.72

Total Wall area (sqm) 170.1

Wall area (excludes windows) 121.4