I have Shimano goretex boots - but they weren't warm enough. There was plenty of room for some medium SmartWool socks - but again, not warm enough. So I put some booties over the top. Still not warm enough - and I'm only in the UK!!!

But now my problem is solved - for Christmas my lovely husband bought me some heated insoles. The battery is in the thinnish sole itself - rather than being a clunky pack. They are fantastic!!! They are called Thermo Sole & come from Germany - they go down to a really small size & come in flat, shaped & remote control.

The company also make heated gloves - so that might be next . . .