I wore my Heattech scoop neck out dancing over the weekend, and while I was really hot, I didn't feel super suffocated or sticky.
If you still need some winter basics, I would recommend stopping by Uniqlo soon because they're having a sale right now on all Heattech - just $9.99 for camis, tanks, long sleeves, short and long bottoms. Some colors and sizes are starting to run out, but they still have a lot of inventory with the exception of full-length leggings. They sold out of almost every size very early in the season, so the only leggings they have left are black size medium. Bummer...! I really wish I had a pair of them right now. Oh well, lesson learned for next season.