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.
They are not very effecient. a wind turbine that is 50 % effecient is very effecient compared to other wind turbines. this is because most of the kinetic energy is changed into heat instead of electrical energy.
Any heater that has the Energy Star label will be very energy efficient. The Honeywell eco line, for instance, are very energy efficient.
Bikes do not require energy like gasoline or electrical power... hence they have no impact on the environment and are energy effecient
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.
The most energy efficient radiator heater is the oil filled one. A better option would be an electrical one because those are almost 100% energy efficient.
Potential to kinetic. Before you turn the shower on, the water is above the ground, waiting in the pipes. Once you open the valve it falls, converting that potential energy into kinetic energy.
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.
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
Same as a modern one. Thay are no more energy effecient.