Most efficient space heater?

[MGB=MPG]

after reading this i just ordered an inexpensive electric oil filled convection radiator type , space/ auxiliary heater , intended for bathroom use. 50 $ delivered from uncle wally . 3 power settings 600/900/1500. . other units i have are 2 each 300W radiant parabolic. 750/1500 quartz type radiant [ the radiant heats objects better than it heats the air. ] these radiant types are more hazardous, news in winter will always report people burned from them and house fires that result from incautious usage.

then the old wood burning fireplaces have gas [propane] logs . these are quite inefficient and are truly emergency heat .we are always in danger of catastrophic ice storms that takes the power out for .. weeks

then i suppose one could consider the 400 Watt mercury vapor , 'Grow Light ' a heater also . it is optimized for visible light but gets plenty hot, runs 6 hours a day winter evenings to night .


efficiency is always related to application . the 300 watts don't throw a lot of heat [ they are considerably more efficient than a 300 watt light bulb, the light bulb element is optimized for visible light with infrared[heat] as a waste byproduct, the heater s element optimized for infrared with light as a byproduct[waste]]
300W is excellent to keep ones feet warm in a cold space.
the 750/1500 radiant will keep one toasty 6 feet back from it in a 40F room , as long as you are in front of it , likewise it will ignite curtains at 3 feet in short order .
i expect the oil filled at 1500W to heat the bathing spaces air in short order from a cold start . and to maintain warmth adequately at the 600W setting
the 600W setting at current rates would cost me 5.4 cents an hour to run. the 1500 W setting 13.5 cents an hour
while the main heat plant is much more efficient[3.7 times as efficient ?]
less efficient space heating of *selected* spaces allows a lower setting
on the main plant and disabling of the aux electric heat, im not sure what the rating is on those resistance heaters organic to the main plant but they are big , on the order of 5-10KW possibly as much as 15-20KW. at 10KW cost per hour would be 90 cents an hour .
in the cold of winter the room temp often falls more than 3 degrees below the set /demand temp at that time the resistance heat would function[were it enabled] i chose to disable the organic aux resistance heat and let the room temp fall as far as it will to the equilibrium temperature. using space heat in *selected*spaces .
it would be an easy matter to enable the first bank of resistance heat with simple reprogram of the thermostat, then there are 2 more banks of resistance heat on a hard switch..
id druther wear a sweater and use the 300 watt to keep my feet warm than spend a dollar an hour or more to heat the whole shebang..,.