How Long Does Heating Oil Last?

Though most homes in the United States rely on electric heat, there are still many regions and many more parts in the world that rely on oil heated furnaces. Particularly in the northern parts of the country and major metro areas oil heated homes are prevalent, necessitating the use of above or below ground heating oil tanks.

Since winters in these areas are so hostile, losing heat could be a life-threatening condition and properly maintaining heating systems along with the oil supply on hand is a crucial fact of life. The first question the resident of an oil heated home should ask is how long their supply of oil will last and under what conditions.

Assuming a typical tank size of 250 to 300 gallons, domestic home heating oil should provide between 1 to 3 months worth of heat depending on ambient conditions and the usage patterns, and it has a shelf life of 1 – 2 years.

Other factors that must be considered include the size and design of the home, the age and condition of the oil furnace, and the overall condition of the tank holding the oil.

You can probably see by now there is much to consider in calculating this equation and if you live in one of these frigid regions it is not something you can afford to answer incorrectly.

In the rest of this article we will go over some of the additional factors mentioned above in detail so you can better estimate how much oil you will need and how long an existing supply will last.

What Affects the Useful Life of Heating Oil? …

There are many variables that affect the useful amount of heat that a given supply of oil can provide as well as the shelf life of the oil itself. Depending on where you live and your specific situation, some of these factors will be of greater or less concern to you.

Don’t let that confuse you, as it is easy enough to figure out what your key performance indicators will be with just a little bit of assessment.

Tank Condition

The condition of the oil tank, above or below ground, obviously plays a major part in determining how long your oil supply will last. Most severely, a tank that is suffering from a slow leak or a significant one is a total showstopper, robbing you of oil and money simultaneously.

Not for nothing, leaking oil storage tanks, particularly ones that are below ground, are major pollutants and can lead to significant difficulty in selling or transferring a property later.

Sometimes, tanks that are very old or newer tanks that are defective from the factory need frequent cleaning subsequent to inspection in order to remove mineral deposits, rust and other contaminants that can degrade the burn performance of your oil and even damage your furnace.

Make it a point to have your oil storage tank regularly inspected and maintained if necessary, especially if you are going to be refilling the tank in the near future.


Probably the most obvious factor affecting the useful life of your oil supply is the ambient weather conditions where you live.

Colder conditions means more heat, more often will be required to maintain comfort or just sustain life. Warmer conditions mean less heat will be required less often.

There are ways to cheat this equation, but only slightly, and if you live in a blisteringly cold region you must be prepared accordingly with a larger supply of oil.

Going back to basics, let us consider an oil heated home in a place where temperatures hover around 50° F during the day.

In this average home that features an average furnace, you should expect to burn about two whole gallons of heating oil per day in order to maintain a comfortable, livable temperature inside.

However, this usage against temperature scale is not linear, and if the temperature were instead about 40° every day the amount of oil consumed to maintain the same temperature inside the home would nearly double.

Considering that most places experience temperature swings, and the temperature is naturally warmer during the day than it is at night, experience will prove to be the best indicator of how much oil you will use per day during various seasons.

Size of Your Home

Bigger homes require more oil to heat them, full stop. Additionally, the taller your home is the more oil that will be required for heating, all other factors being equal. Homes with high ceilings are notorious for being inefficient users of heating oil.

Consider this: A two-story, five bedroom home with grand, tall ceilings will need drastically more heating oil under identical conditions and assuming identical construction factor then will a small, one story ranch home.

That’s just the way it is, and considering that most home improvements will lead to only fractional increases and heating oil consumption efficiency, you should carefully consider the size and the layout of the home before purchasing it if it is in an area that relies on heating oil.

Design of Home

As you might expect, the design and construction of the home is another major influence on how rapidly it will consume heating oil.

Drafts are the enemy, and a home that is properly insulated, thoroughly sealed and constructed with an eye towards efficiency and reducing waste will use less heating oil then will an old home that is drafting and poorly insulated.

The exterior cladding of the home does play a part, with stone, brick or earth having an advantage over wood or vinyl siding, but this is secondary to sealing and insulation.

Happily, it is possible to dramatically improve your home’s draft protection by meticulous inspection and remorseless hunting down and subsequent closing of cracks, gaps and any other spaces that will allow cold exterior air to rush in or your precious warm, heated air to escape.

Occupancy Status of Home

Just as important as the size, layout and status of the home is the status of the people who inhabit it. your home only needs to be heated while you are in it for you to be comfortable, and if the home is routinely unoccupied then the heat can be turned down or potentially even turned off while you and your family members, if any, or away in order to save oil.

If your home is unoccupied for long stretches of time while you are at work, school or anywhere else consider dropping the thermostat dramatically to likewise dramatically cut back on the amount of oil being consumed.

The viability of this technique will depend on your preference and comfort, and perhaps whether or not you have a thermostat that can be set with a scheduler function.

Even if you are only saving oil for a handful of hours a day, the savings do add up, and saving even a single gallon per day translates into nearly one hundred gallons over the course of a season!

Furnace Condition and Features

It should not be a revelation that the condition of the furnace also plays a major part and how quickly oil is consumed in your house.

A furnace that needs a tune-up, is dirty, or malfunctioning is not going to burn oil very efficiently, and that means it must burn more oil to produce the same amount of heat that it would normally if it were operating correctly.

Whatever vintage furnace you have, new or old alike, make sure you regularly maintain it and also schedule periodic inspections and parts replacements as required if you don’t want it to guzzle oil.

A properly working furnace in conjunction with a well-designed, well sealed house will use dramatically less oil than it would if both were neglected.


Determining how much heating oil you’ll need is only a matter of figuring out how long it will last under what conditions. Many variables change the equation, including the design and upkeep of the home, the age of the furnace and the condition of the tank that the oil is stored in.

Generally speaking, an average home with an average size tank experiencing an average winter should expect their oil to last between 1 and 3 months depending on usage tempo.

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