How do I know when my heating oil level is getting low?
If you have a digital monitor
If your tank has a digital monitor that plugs into an electric socket inside the house, such as an Apollo or Watchman, the ideal time to order is when the digit reaches 2 (2 bars).
No gauge?
The best and most reliable way to check your heating oil level is to dip your tank – or you may just want to double-check the accuracy of your gauge.
To avoid contamination, make sure you use a designated dipstick that is kept clean and used solely for your oil tank.
The least effective and most unreliable ways to check your heating oil level are shining a torch in or tapping the tank.