Reading an Oil Tank Gauge

Posted on by Steve Williams

Got heating oil? In this post, we’ll break down how to read a heating oil tank gauge. We’ll also explain how an oil tank gauge works and when to order oil.

How an Oil Tank Gauge Works

A home heating oil tank usually features an internal tank gauge. This tank gauge has a few components:

  1. A float on the end of an arm
  2. A sight glass (ok, it’s actually plastic)
  3. A disc that rises and falls with the oil level
An oil tank most commonly features an internal float gauge as shown here.

Reading a Tank Gauge

The oil tank gauge features a disc that is visible at the top of the tank through a plastic sight. The sight features tick marks indicating how full the tank is. Look at where the top of the disc lines up with the tick marks to determine the current level in the tank.

Look at where the disc lines up with the tick marks to determine how much oil is in the tank. Always remember to reorder at a quarter of a tank to prevent a runout.

How Much Oil Should I Order?

How much oil you should order depends on the size of your tank, as well as how full the tank is. Use the guide below to determine how much to order. For twin tanks, simply double these amounts.

If you’re down to 1/4 tank, you can safely order 150 gallons. If you order 200 gallons and your tank does not take the full amount, you may end up paying a higher price per gallon.

Types of Oil Tank Gauges

Float gauges like the one above are not the most reliable tank gauges. They can wear out or get stuck over time. Further, they can end up with sludge on the float.

Float gauges can end up with sludge as shown here, which can greatly affect the tank’s readings.

Float Gauge

This is the most common type of tank gauge and comes in a few varieties. The floating arm type, shown above is common in traditional steel tanks. There is also a string type that is common on Roth tanks.

A float gauge with an arm, left, is most common. A less common float gauge (right) has the float connected to a string. A gear system moves the needle to indicate the level.

Dip Stick

The tried and trusted method for being completely sure of your oil tank level is the old-fashioned dip stick. Use the dip stick to measure how many inches of oil you have. Then, refer to an oil tank chart to determine gallons.

Use a collapsible oil tank dip stick to measure the number of inches of oil in your tank.

Smart Oil Gauge

Perhaps the best invention since the discovery of heating oil is the Smart Oil Gauge. The Smart Oil Gauge uses an ultrasonic sensor to measure the oil level. The device connects to WiFi and uploads readings to the cloud. From there, you can check the level via an app on your smart phone.

The Smart Oil Gauge not only tells you exactly how many gallons you have, it also tells you how much oil you are using and gives an estimate of when you’ll need oil next. It sends you low-level alerts, and lets you reorder oil right through the app.

The Smart Oil Gauge threads into the top of the tank. You can check your oil level from anywhere.

Choosing the Best Type of Oil Tank Gauge

There are pros and cons to each type of heating oil gauge. The float gauge gives a good estimate of the oil level. A dip stick can be more precise, but is cumbersome. The Smart Oil Gauge can be read remotely, but requires WiFi. Use the guide below to choose your oil tank gauge.

The Smart Oil Gauge is the best choice for monitoring your heating oil tank.

Tips for Reading Your Oil Tank Gauge

Knowing your own heating oil gauge is important. Some gauges read high; others low. If you want to be sure your float gauge is accurate, we recommend checking it using a dipstick. If you purchase a Smart Oil Gauge, make sure you input the correct tank style (e.g. 275 vertical or 330 horizontal) into the app. The app will adjust the readings based on this.

If you are relying on a float gauge, remember that it will only provide an approximate level. It should not be relied on as a precision device, and can definitely not be relied upon when the tank is nearly empty.

Happy heating,

Steve