One of the best gadgets i have ever got for biking is a heated under jacket. only £40 on flea bay. mine was described as being recommended by BMW owners club. I got a second one for partner for only £36. seller said he rewards repeat business.
mine plugs into a cigar lighter sockets . mounted at both end of my thou. Our jackets have no temperature controll ,but its never been an issue . Other more expensive jackets have controllers and also battery packs , but you pays yer money etc.
Worn under our Buffaloe armoured waterproofs+heated grips perfect. Without active heat, no amount of warm clothing will compensate for a 80mph and minus temp's. Coming up to the 3rd winter now, cold weather no probs!