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Feb 17, 2023 2:11:41 PM by Logan Donahue

Why You Shouldn’t Let Your Oil Tank Get Too Low

During the coldest nights of the winter, a homeowner's worst nightmare is to run out of oil. There are many reasons to not let your oil tank get too low -- besides running out on the coldest night of the year. So, other than running the risk of no heat in the middle of a Delaware Valley winter, what happens when you get too low on oil?

How low should you let your oil tank go

A typical above-ground, horizontal oil tank is about 275 gallons. The amount in the tank is measured by a dipstick with inch increments on it, which is essentially a ruler for your tank. Your furnace or boiler will most likely stop running if you let the oil level get down to about four inches, or about 32 gallons.

How to Check Your Oil Tank 

You can also monitor your fuel use by frequently checking the fuel depth. But beware -- this can be deceptive, as the bottoms of most oil tanks are rounded. This means that the inch mark on the dipstick at 20 inches represents a lot more fuel than the inch mark at five inches. While it may take several days to drop from 20 to 19 inches, you could burn up the fuel from five to four inches quite rapidly in a day, and you might find yourself without heat until you can get a delivery. Here's a chart that resembles one you can get from your oil delivery provider. 
275 gallon horizontal heating oil tank chart
Homeowners should be checking the amount of oil in their tank regularly and get a refill when it is about 25 to 30 percent full. Running out of oil isn’t only inconvenient, but it can create problems in your tank, too. 
ECI's oil heat service plans allow for our customers to worry less. We can automatically deliver your oil based on specific system projections, ensuring that you never run out. Check out our delivery options below!
Oil Heat Service Plans

The Damage of Low Oil Fuel on Tanks

Running too low on oil can cause a whole host of problems, including issues with both your oil tank and HVAC system. Let's discuss them below. 

Tank condensation

When fuel is low in a tank, condensation builds. Outdoor, above-ground models commonly accumulate condensation on the interior walls, resulting in an ideal environment for bacteria. The bacteria will then turn the oil into sludge on the bottom, which will indicate a deeper fuel level than what's there. So running low on oil can lead to a vicious cycle of always thinking you have more than you actually do, and continuously running low. 
Condensation also encourages bacteria and other microorganisms that will break your heating oil down to thick sludge that can clog your piping system.

Clogged filters and nozzles 

When you let your oil get too low, there is also a greater chance that water and impurities will be sucked into the feed line. This can clog the nozzle and prevent the burner from operating properly, upping the risk that you'll need to schedule a service call. Spray nozzles in an oil tank become clogged when sludge is present around the area. This can produce a foul odor, which is another sign your tank needs a refill. When oil filters become clogged with debris, your oil tank will most likely fail. 

HVAC damage 

When debris or impurities accumulates and gets sucked into the feed line without being stopped by filters, it can potentially damage your HVAC equipment and rob your system of efficiency. If your HVAC system is damaged, it can spread problems to the rest of your home. 


ECI Comfort offers a full-service oil contract where we track your usage using a calculation of heating degree days. We then schedule your oil delivery before your tank gets too low and ensure that you never run out or run into issues that can ruin your HVAC system (or your day!).

Save More on Oil 

Keeping your tank full keeps your overall system healthy. Homes can go through a surprising amount of heating oil just to keep their water warm in the summer as well. Additionally, there are possible savings you could encounter by getting an oil delivery in the off-season. Buying oil in the offseason is a good way to minimize expenses and save time when demand for oil spikes at the beginning of the cold season. 
Aside from buying fuel when prices are low, some of the best ways to save money on heating costs are to keep up with annual heater maintenance, set back the thermostat at night (five degrees or more), and air seal and insulate the house.

Choose MyExpressOil for Fast Delivery

Choosing an automatic delivery plan with ECI Comfort or express delivery service with My Express Oil can help you save money on oil deliveries and avoid unwanted issues. 



If you live in the Delaware Valley/Greater Philadelphia area and would like to find comfort within your home, visit our website or give us a call at 215 - 245 - 3200 to learn more.


This entry was posted in Heating, Home Performance, Service Contract, Fuel Oil, Oil Tank, Home Maintenance

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