According to this article it's amazing your heating oil lasted 7 years. They say 18-24 months for the shelf life of heating oil!
What Makes Heating Oil Go Bad?
heating oil shelf lifeIf you are going to store fuel oil for a long period of time, it can begin to degrade due to various reasons. First, the bacteria in your oil tank and in the oil itself can degrade the oil over time. Next, oil and acids can greatly decrease the shelf life of your oil. Water can also impede the combustibility of your stored oil. To keep these things from happening, you need to make sure that your oil tank is sealed properly. Thirdly, there are certain contaminants such as curd, paint, sludge, and rust that can make your oil go bad over time.
Before storing oil…
you should make sure that the oil tank is clean. It is best to use premium oil because it has additives in it that will reduce the amount of sludge and sediment that can accumulate in the tank. Also, you should never store motor oil in your storage tank, even if it is empty.
Typical Shelf Life Of Heating Oil
Typically, fuel oil can last between 18 and 24 months without decaying. This is true as long as it has the right additives blended in and if it is stored correctly. When the proper additives are put in the oil, it will stabilize it, increasing the shelf life. When the oil is delivered to your home, additives should then be introduced. High-quality oil also has additives already added to prevent sludge and sediment from building up.
It is important to understand…
that if your heating oil is already beginning to degrade, there is nothing that you can add to rejuvenate it.
As mentioned above, you need more than the right additives to keep your heating oil in good shape. The condition of your storage tank will also increase the shelf life of your oil. You should make sure that your tank is sealed well and free from anything that could contaminate it. Also, try to figure out how much oil you are going to need for the heating season. This will allow you to order just the right amount. If you have too much left over after the heating season and your tank doesn’t properly store it, your oil company might need to remove it, which will cost you more money.