My wife has suggested side opening windows rather than bottom opening, which are apparently quite common in the UK. I don't really mind either way, but I'm interested in peoples practical experience. We will have to have a couple bottom opening, for example above the kitchen bench, because we couldn't reach side opening up there. In practice I'm told both can be left open when it's raining, though I wonder if one is better than the other. Either type can be locked slightly open for ventilation. Side opening can open wider to allow more air in when we're home, which might be helpful occasionally.
Our main aim is just a modern, easy to use window with good thermal and acoustic properties, which both styles will do. As a second priority we'd like a reasonable amount of ventilation when the windows are "locked open", and we want to be able to leave the windows locked open regardless of the weather. We have a ventilation system (a cheap one) and two air conditioners. Our kitchen area, with three windows, gets heaps of sun and can hit 35 degrees in the middle of summer.
Does anyone have any thoughts or practical experience about side opening windows?
Here's a random image from Google of a side opening window to show what I mean by side opening. Ours will open outwards.
Ours will look more like this, with the bottom 2/3 opening, and the top 2/3 fixed glass that won't open. We'll only have one opening part per window, not two sets of two as shown below.