One of the strongest criticisms I have heard of Paul's article is "but not all of us sit at a desk all day." But rather than throwing in the towel, I think the thing to do is find different ways of applying the micro heater ideas to various scenarios.
One scenario is sitting on the couch. I think this one is pretty similar to the desk scenario. Light bulb above the head, dog bed heater for the feet, and maybe a nice blanket.
Another scenario is kids. My experience with kids is that most of the time they are too warm because they are running around a lot. So this would be fine. For when kids are playing on the floor in a more relaxed time, some well-placed incandescentlights and some heated mats could be a good way of creating a micro heat bubble.
Good topic. I mess around with various energy and heating systems and ideas. I’ll name a few: small electric dish radiators. They are like sitting next to a hot fire with the infrared radiant heat directed in desired direction. I’ve seen small radiant heating elements of 250 watts that thread into a light bulb socket. A nice dish could be fashioned to make this a very effective heater.
I looked on Amazon and there are dozens of inexpensive heat mats. Both for industry or for health purposes. I know of someone who has a 3 gallon solarshower bag on his dashboard with a 60 watt heat mat (12 volt) under it. With the combination of sun on top and electric underneath he always has warm water. The bag can be used as a hot water bottle if not used for shower.
Hydronic heating can be “micro heating”. My Motorhome has PEX tubing going from the floor heat tubing to a small 4 horsepower Diesel engine that charges my batteries. I can preheat the engine to start it and heat the floor when it is running. The floor essentially becomes the radiator. There is also PEX tubing going to the shower which has a small radiator. I keep it warm enough for plants in the shower. I could run PEX tubing to whatever I wanted. It will be connected into a batch rocket water heater before next Winter. Currently it is heated by a small custom propane water heater as my heating needs are relatively light here in the Puget Sound area. I used maybe only 35 gallons of propane last Winter so I didn’t finish building a wood fired heater.
I started reading about far infrared heat panels. I thought about a couple of these on the ceiling in strategic places like above a favorite seat or above the bed. Then I remembered I have a roll of heat mat for greenhouse use. It is 6 feet long and I measured 105 watts consumption. It is warm to the touch and was nice above my bed.
It’s nice to have something to simply “knock the chill off”. Micro heaters can do this. Another good strategy is to have a big heater that is only on a few minutes then a small heater that takes over to “keep the chill off”.
As fabric and battery technology increases I imagine we will see more solar fabric and heated fabric. There’s massive research going into these.
Good Old Raisins and Peanuts, GORP, is the heater we used when I was a outdoorsman. Take a few into the tent to stay warm at night too.
If someone is moving around a lot and still can't keep warm, there's a thing called a Heat Vest. I'm most familiar with Cool Vests, which are used by entertainers who have to wear hot costumes, and have not used either the cooled or heated kind personally, but they are out there. Not inexpensive.