I created a simple house (only one zone with a roof on top) for Melbourne, Australia Climate: the roof is metal decking, ceiling is insulation of R5.0 m2.K/W, external wall is brick veneer with insulation of R1.5 m2.K/W, floor is 0.1m concrete floor on slab.

I changed floor insulation and external wall insulation separately and both results are quite strange:

1. when I add insulation of R0.3 m2.K/W to floor, the indoor operative temperatures will change a lot (max difference: +7°C/-3.1°C).

2. If I change the wall insulation from R1.5 m2.K/W to R10 m2.K/W, the indoor operative temperatures will only change a little (max difference: +0.6°C/-0.58°C) and values of the External Wall Average Face Conduction Heat Transfer Energy will be quite similar.

The results seems not corret as insulation of R0.3 m2.K/W to floor shouldn't has such large effects on the indoor temperatures and the average face conduction heat transfer energy of external wall shouldn't be similar for insulation R1.5 and R10 m2.K/W.

Please see the link I have put my modelling and comparison of the indoor temperatures in the dropbox: https://www.dropbox.com/sh/91fypsn1d2...

Does anyone know why the effects of the insulation of floor on indoor temperatures is so huge and the insulation of external wall has such small effects on the conduction heat transfer energy?