Buy your heating oil and fill your tank on the very cold days. You pay for your energy by the pound of fuel not the gallon. The energy of a lb of oil is measured in BTU. The colder the oil the more it weighs (more dense) and therefore the more lbs (BTU's) per tank. When the fuel warms up in your tank (assuming it's inside the house) it will expand to account for the change in density (function of temperature) but the number of pounds remains the same. Obviously, assumes that the oil temperature in the delivery truck is close to the ambient temperature. When the temperature is close to 10 below zero, as it was the other day, that would make about an 80F change in oil temp after it reaches room temp. I'm guessing that the density change is approximately 2% for a 50F change in temperature; so you'd save a grand total of about $4.00 on a $200 fill up on a zero deg day. Not much but it's fun to think about it. Hm-m-m-m same applies when filling up you car gas tank MLD
- posted
20 years ago