Double Storey Too Hot Upstairs

Hi, anyone here live in a high performance double storey home? I'm interested to know how hot it can become in summer.

I have a high performance single storey house in Ballarat and I'm loving it. We don't have any sub floor heating and our heater is only switched on probably 10 times a year. Each time only for 3-4 hours. In summer, it's always cool inside the house when it's very hot outside. Our house is West facing (front of the house facing West).

We recently bought a new block of land (32m W x 62m D) and it's North facing. I didn't know how bad North facing is until I started looking at floor plans. Because the width is only 32m, we aren't able to fully utilize the land and now I'm looking at double storey floor plans. Thus.... I want to know if anyone here can share their experience of living in a double storey high performance home (air tight and fully insulated).

Thank you! Cheers.

High performance requires Engineering Multiphysics simulations in Housing
BTW, experience has nothing to do with energy transfer, its a science and
architect /designers do not use ansys and comsol software.
OT, when the market moves that way and clients are prepared to pay big bucks, then engineers may show an interest.
ATM, simulating the Build/Engineering showing optimisation ie, materials, labour, costs, etc, is No1 priority on builds
check the real surveys
Cheers
Chris

Someone I know built a 2 storey high performance home in Adelaide. The downstairs doesn't require cooling. However, the upstairs has split systems as it is noticeably hotter in summer as the hot air rises upstairs. They need to run the AC in the summer time upstairs. There is no seal between the two floors (i.e. the staircase is completely open to upstairs). I was there on a 33 degree day and you can feel the difference. Didn't need cooling that day but they would once it approaches 40. Not sure how it performs in winter, but I imagine may be the reverse where the upstairs is fine as the warm air rises leaving the downstairs cooler.

That being said, they don't have to run the AC often and their upstairs would be a LOT more comfortable than a standard 2 storey house. Their split systems are also very efficient so they don't need to worry too much.

They have said if they were to do it again, they would design it in so the two floors can be sealed off. Doesn't look as nice though I suppose.

Talking to some builders, it seems like a common problem with double stories even if air tight and well insulated/orientated.

Unless you have double glazing, nothing will be high performance. Glass is the largest transfer of energy in and out of a building.

You may have no insulation upstairs in the studframe or roof.

Frankly speaking, in a typical house around 30-35% of the energy will be lost through walls and around 25-35% through the windows and doors (depending on glazing ratios). Around 25% goes out through the roof too.

So, for effective insulation, all 3 areas (actually 4, plus floors) should be considered.