Cooling via transfer upstairs??
Our house is challenging to cool and has 3 different temperature zones.
It's a 2 story house built into the side of a hill. Downstairs is partially underground, gets almost no sun and is cold and damp, consequentially we avoid it in winter which we can because it's just garaging and some spare rooms. Upstairs we have a split pitched roof with a 4m high central hallway that runs the length of the house. One side of the house has very high ceilings, the other regular height, both sloped. The side with the normal height ceilings gets more sun in winter so is quite a bit warmer. In summer when the sun is higher, the high ceiling side is actually hotter as it gets roasted by the afternoon sun. It is a skillion roof so there is no ceiling space for HRVs, central heating ducts etc.
There are 3 places where I might be able to pump cold air up from downstairs in summer. Not sure if this is a good idea as it will be more damp. Not winter level damp but still damp.
To get more benefit I thought about reversing the flow in winter but the upstairs where we live, needs all the heat it can get.
Oh and I have priced up heatpumps, just considering all options :)