If you put ten joules of electric energy into an electric heater, out will come ten joules of heat. Is there any way in actual practice that you can get more than ten joules of heat from a device if your electric energy input is only ten joules?

A) No, this would violate the 0th law of thermodynamics.

B) No, this would violate the 1st law of thermodynamics.

C) No, this would violate the 2nd law of thermodynamics.

D) No, this would violate the 3rd law of thermodynamics.

E) Yes, many people own such a device.

Solution: E. The device is called a heat pump. While "something for nothing" is an overstatement, you can get more than you pay for with a heat pump. It is certainly possible to put in 10 J of electrical energy to pull 15 J of thermal energy from a lower temperature system (outside your house) and send the combined 25 J to the higher temperature system (inside your house). You get 25 J, while you only pay for 10 J. This in no way violates a law of thermodynamics. The trick is that you don't have to pay the outside air, earth, or water for the heat you take from it.