I think that rather than go out and buy a bunch of light bulbs, they should (perhaps) go out and buy one or two of these. I think they would be many dollars ahead (therefore, using less energy).
Granted, the wofati or the rocket mass heater is far better and far better permaculture aligned. But, I suspect that this contraption would help get one a little closer to these things. If nothing else, then they get a better understanding of the value of conductive heat over convective heat: a primary component in the rocket mass heater.
I now have tried several experiments and am still experimenting.
Here is some interesting info I have so far:
With a room temp around 58 degrees F, I can run my personal heater under my desk at 700 watts. But then it is too hot - and even then my fingers start to get cold.
I bought a heat pad and I borrowed a heat pad. The each use about 30 watts. I put one under my butt and one under my feet. The design of these things is that if you set them for a low heat, they do something like a minute on and two minutes off (as opposed to just "on" all the time) an the time they are on it is too hot. It would be nice to have a design where there might be three sets of coils and "low" has one set on all the time and "high" has three on all the time.
With the one pad at my feet and the other under my butt, it is still a little too cool.
I attempted to add in a 60 watt radiant heater (non light type) and have it on 24x7 (thereby warming the floor where my feet are) but it was just too little. I put in a 250 watt infrared lamp that is on only when I am at the desk. I find that between the two pads and the lamp, I am as comfortable as if I were in a room that was 72 degrees F and the thermometer at arms length away reads 58. And, I suppose that on the other side of the room it might be much lower - 55? 53? And the part of the house just outside my room is 50.
So the house temp is set to 50, leading to some very significant savings. And I feel like I'm at 72, but currently using about 300 watts.
I estimate all day use of this to be something like 56 cents per day. $16.80 per month.
I would also think that a better designed foot mat and chair/chair mat would lead me into being more comfortable with less than 100 watts.