trianglman's Journal: What gas companies don't want you to know

There is a known secret all gas sellers know but don't want you to know. When you pay for gas at the pump, you may not be getting the gallon you think you are getting. The problem is this, gasoline, like all liquids responds to temperatures by expanding or contracting. When temperatures are lower, gasoline is more dense, when it is higher its less. The amount of energy gas contains is based on this density. Wholesalers and the government have known this for years, thats why there is a standard for determining the power of gas - 1 gallon is 231 cubic inches at 60 degrees Fahrenheit.

But this standard is thrown out the window at the gas pump. Gas thats 90 degrees at the pump could have expanded by about 2-4%. This may not seem like much per fill-up, but thats estimated to cost Californians alone $450 million. This also works in the consumer's favor in colder climates, where temperatures are regularly below that 60 degree standard. Gas companies have fixed that issue in Canada by passing legislation allowing fuel retailers to install pumps that adjust for the temperature difference. They don't like taking things the other way though. When Californian consumer groups attempted to get these pumps installed in California, the pump manufacturer suddenly canceled its plans to sell the equipment there, after regulators approved it.

The problem: Gasoline expands as it gets warmer, becoming less dense. But most American gas pumps dispense the same volume -- 231 cubic inches per gallon -- and don't compensate for temperature. That means a gallon of hot gasoline has less energy than a gallon of colder gas.

The cost: One study estimated that Californians would save $450 million if gas pumps compensated for temperature. Consumers across the country would save $1.7 billion.