Prevention is the best medicine – it’s true with people, and it’s true with heating oil tanks.
A heating oil tank isn’t a complicated machine – really, it’s just a big steel box with some valves. But when that box is empty (or nearly empty) of heating oil, an uninvited guest can arrive in the internal tank environment as weather conditions change: water, in the form of condensation.
Condensation inside your heating oil tank creates humidity, and humidity in a dark, enclosed environment is rarely a good thing for a steel structure. Water, being heavier than oil, will naturally gravitate to the bottom of the tank, corroding the steel wall and potentially leading to a tank rupture. Worst of all, you may not see it coming, since the tank will be rotting from the inside out (actually, even worse than that is the reality that your homeowner’s insurance probably won’t cover the damage caused by the resulting oil spill, which could cost tens of thousands of dollars to remediate if your tank is outdoors).
But that’s not all the trouble condensation can cause in your heating oil tank: the presence of water also creates ideal conditions for bacteria growth in your fuel, which will turn your heating oil into line-clogging, efficiency-robbing sludge.
The bottom line: Condensation and heating oil tanks are not a good match.
The good news is you can greatly reduce the risks associated with condensation by keeping your heating oil tank at least half full year round, especially in the heating offseason. Even better news is that an offseason heating oil top-off could save you money, too, since pre-season heating oil prices are often lower than in-season prices, when heating oil demand and market prices are highest.