is it true the payback time of installing something that makes a home more energy efficient is the time taken for the cost of installation to be matched by the money saved.

What tightening torque should be used for a hexagonal head screw (not split-bolt) on a 250 kcmil conductor?

What is a possible result of higher air temperature caused by global warming

Since the energy was not raising the temperature of the water during these segments, what was the energy used to do instead? your answer must include an explanation of what is happening to the molecules.