Based on years of office, hotel, and meeting room experience I believe that we will have truly advanced as a society when we master indoor temperature control. When in July people are bringing sweaters to wear inside and are putting space heaters under their desks, there must be room for improvement. Perhaps the last mile of this problem has less to do with the heating/cooling technology itself, and everything to do with how we express our feelings to the machines that control the flow of hot and cold air.
Consider the thermostat. in The Design of Everyday Things, Don Norman addresses the well-intentioned but counterproductive way we interact with them. If we're a little cold, we turn up the temperature a little. If we've very cold, we turn it up a lot--often to a much warmer target temperature than we're interested in, because we think it will warm up faster that way. Of course that's not the case, and I can't tell you how many times I've walked into a sweltering room only to see that the thermostat was set to 85 degrees.
It occurred to me the other day: what if you didn't give it a temperature at all? Truth be told I don't care what the number is as long as I'm comfortable. Rather than inputting a number, perhaps the thermostat of the future will only require us to tell it if we are hot or cold. Then it can make the adjustments and check in to see if we're happy with the result.
From the user's perspective the number is just an arbitrary scale to represent comfort. Why not do away with it and focus on the comfort itself?