Like Dotty we have a 1 tog for summer which we bought from Dunelm quite a few years ago & sleep with windows open. In fact we have 2 x 1 tog to use one on top of the other on cooler summer nights when OH can't stand the 1-tog alone! Have an oscillating fan on during the evening with all upstairs windows & doors open for through draft & this stays on for a while when we first go to bed as the bedroom is like a greenhouse in summer, despite blackout blinds & thick curtains being shut all day to keep temp down.
In Winter we have a 2.5 tog feather job. Very lightweight, fluffy & my favourite for the luxurious feel of it. Whatever the tog, all have to come off (my side) several times a night, winter & summer due to overheating, still ongoing in my 14th year of symptoms. Have tried with just a sheet in summer but I need more weight than that in order to fall asleep. OH puts thick dressing gown on top of his side of the duvet most of the year! Prior to menopause, in winter we used a 13.5 tog & 15 tog one on top of the other & one or the other the rest of the year!! We have a vast collection now - 2.5 tog, 3 tog 4.5 tog, 9 tog - all bought during peri, the latter 3 not used for the last decade or more!