Keep-full is a delivery plan where the supplier, not the customer, decides when to fill the tank. The supplier watches the tank and tops it off before it runs low.
On a keep-full plan the customer never has to call and order. The supplier takes on that job, predicting how fast the tank is draining and scheduling a delivery before it empties. It is most common with home heating oil and propane, where running out means a cold house and a service call to restart the system.
The prediction is the heart of it. The supplier uses degree days, a simple count of how cold each day has been, along with the size of the tank and the customer’s past use, to guess how much fuel is left. Get it right and tanks never run dry while trucks still run full, efficient routes.
It is good for both sides. The customer stops worrying about ordering, and the supplier gains a steady, plannable book of deliveries instead of a flood of last-minute calls when the weather turns. The trade-off is that the supplier carries the risk of guessing wrong.
In useThe homeowner is on keep-full, so the propane company tracks the cold and tops off the tank on its own, and the family never thinks about ordering all winter.
See also Heating oil, Propane (LP-gas)