New here, so apologies for the basic question.
My undergraduate-level physics understanding of efficiency is it is the % of energy input that is turned into useful work as opposed to heat. At the same time, I've been told that free-standing space heaters waste energy because they are "inefficient". How can something that is designed to produce heat be considered inefficient?
Similarly, is there any reason to care about the efficiency light bulbs if I live in a climate where it is always cold outside and both heat and light are desirable things for a light bulb to produce?