Motorcyclists provide an interesting example of this principle. The extreme windchill experienced by motorcyclists makes it very difficult to keep warm - a rider travelling at 70mph at 0°C experiences a windchill of -18°C.
Many riders in northern climates use electrically heated underclothing, which, in conjunction with an insulated outer layer, can keep a rider warm with just a few watts. Better battery technology could make such garments commonplace.
Milwaukee Tool came out with a line of heated jackets, powered by the same batteries that power their drills and other tools. I believe the red ones were the first ones out, then they saw a market in the hunting crowd and came out with the camouflage version.
Some heated motorcycle jackets can be plugged to the bike's battery (you just have to install the plug somewhere accessible and connect it to the battery.) Then when you get on your bike you just have to connect your jacket and off you go. The alternator provides the power during your ride.
Many riders in northern climates use electrically heated underclothing, which, in conjunction with an insulated outer layer, can keep a rider warm with just a few watts. Better battery technology could make such garments commonplace.