Save gas money in the morning?

Do you pump gas in the morning to save money? You may consider sleeping in.

According to a Consumer Reports article, you won't save money by pumping gas early in the morning. The advice is to pump gas in the early morning before the heat of the day causes the oil to increase in volume. The early morning gasoline will be denser, meaning you'll get more energy per gallon than later in the day. As gasoline goes from 60-75 degrees Fahrenheit, it increases in volume by 1%, while the energy content remains the same.

The facts are true, but the advice is not. Gasoline is stored underground where the temperature variation is little or none at all throughout the day. Craig Eerkes, former chairman of the Petroleum Marketers Association of America talks of an expansion of gas with a change in the day's temperature. Eerkes calls the change, "Just so, so minuscule as to be almost nonexistent." The first few gallons at the pump may be slightly warmer than the gallons to follow, due to the gas sitting in the pump dispenser which was warmed by the sun. Aside from that, the time of day will not make a difference in the weight of your wallet.

Judy Dugan, Research Director for the California advocacy group Consumer Watchdog, says, "If fuel is warm when it’s delivered to a station, it’ll still be warm when it’s sold a few hours later." So the real advice? Go to the pump whenever you would like. The gasoline temperature will not increase with the afternoon sun.