The trick with the HAB, I found, was to wear thin layers underneath - yes, even in a cold Melbourne winter! Not only because of the shared body heat, but because the HAB sits nicely under jackets and shawls that you put on to keep extra warm if you need it When I started using the Ergo I had to judge the day better because jackets and things look bulky underneath...but by then it was summer and not so much of an issue. Looks like will be the same again for us, this time round, and will be toying with the idea of the Sleepy Wrap, a woven wrap or some such thing until the kidlet is big enough for the Ergo (don't actually fancy the idea of the Ergo for a smaller baby, the insert seems a bit fiddly when I could just pop the kid into the snuggly hole of the wrap!).