In 2010 we use loads more energy than we used to use. We don't have enough trees to absorb the carbon dioxide that the houses emit.
Insulation conserves energy by keeping heat/cold inside so you don't have to use a heater or AC.
I learned to be safe with energy to keep the electrical sockets enclosed. I learned to stay away from electricity when you have water.
Fuels like gasoline pollute the earth. But fuels like vegetable oil fuel don't pollute the earth.