Even a new, minimum efficiency air conditioner or furnace can be a significant jump in efficiency. The old furnace in your basement may only be originally rated at 60% to 70% AFUE. In order to comply with national regulations, furnaces manufactured today have to be rated at a minimum of 80% AFUE.
dipole - a pair of equal and opposite electric charges or magnetic poles separated by a small distance. couple - (physics) something joined by two equal and opposite forces that act along parallel lines. electric dipole, electric doublet - a dipole with equal and opposite electric charges.
Molecular Dipole Moments. Even though the total charge on a molecule is zero, the nature of chemical bonds is such that the positive and negative charges do not completely overlap in most molecules. Such molecules are said to be polar because they possess a permanent dipole moment. A good example is the dipole moment of the water molecule. Molecules with mirror symmetry like oxygen, nitrogen, carbon dioxide, and carbon tetrachloride have no permanent dipole moments.