Look for any with an energhy star lable but the Amana 12000 BTU Energy Star Room Air Conditioner with 11260-BTU Heater is good.
An example of an energy efficient device includes an energy efficient light bulb.
Any heater that has the Energy Star label will be very energy efficient. The Honeywell eco line, for instance, are very energy efficient.
The question is better defined as "What the most energy efficient portable heater?" Because one would assume that you will want to be able to take the heater with you when or if you move.
Bikes do not require energy like gasoline or electrical power... hence they have no impact on the environment and are energy effecient
the most effecient use of tranport is the horse
An HP copier is very effecient and effective.
Vornado is the brand of heater that is the most energy efficient. If used properly, Vornado heaters can heat just as well as a larger heater, for a much lower cost. They are small, portable, and can heat large rooms. Some of them even have thermostats or timers to increas efficiency.
The original energy store used by a heater is electrical energy. This energy is converted into heat energy by the heating element in the heater, which then warms up the surrounding air or space.
A heater typically transforms electrical energy into thermal energy, which is then emitted as heat.
One of the most energy efficient water heating methods is the heat pump water heater. This method is proven to be two times more efficient over the standard electric water heater.
Same as a modern one. Thay are no more energy effecient.
A heater is a machine that converts electrical chemical energy into thermal energy. Energy can not be created nor destroyed, only tranferred from one form into another. this is why in most heaters some of the chemical energy used is also transferred into some waste energies, eg: Light energy