ETA - yep I hang out at home in shorts and a t-shirt (or my pj's if I'm in a lazy mood lol). I usually keep an abaya (a long dress/robe)around to chuck over the top in case of unexpected visitors but sometimes I can't find it in the chaos and then I have to run around like a mad woman looking for it - it's a bit embarressing.
Hee hee, I have the same problem at home - it gets really really hot up here and most days I just slob around in my undies (sorry if TMI). I have a couple of summer dresses that I keep by the door for such emergencies but almost always manage to open the door then realise that I've thrown them on inside out! Such a good look!