A keep-full program is automatic delivery: the distributor forecasts each customer's usage and delivers before the tank runs low, with no order call needed. For the distributor it turns one-off orders into predictable, routable volume. The trade is owning the forecast. A missed delivery is a run-out, and a heating oil run-out means a no-heat call, a line bleed, and a restart visit, usually at your cost.
What it is
The distributor tracks each tank on the program, estimates how fast it is drawing down, and schedules a delivery before it gets near empty. The customer never places an order. Heating oil and propane shops have run accounts this way for decades because it locks in the gallons and lets them plan routes weeks ahead.
Keep-full vs will-call
With will-call, the customer calls to order when the tank gets low. With keep-full, the distributor handles it, forecasting usage and delivering on a schedule. Keep-full is more convenient and more efficient to route, but it depends on good forecasting, the two delivery styles laid out in the heating oil business.
Who it suits
Customers who do not want to watch their own tank and cannot afford to run out: home heating oil and propane customers, farms, and steady-use businesses. For the distributor, keep-full accounts are predictable, routable, and loyal, which makes them valuable.
What makes it work
Accurate forecasting of each customer's usage, often from consumption history and weather data like degree days, so deliveries land before the tank empties without wasteful early top-offs. Heating oil operators do this with a K-factor: the number of heating degree days a customer goes through on one gallon. A house with a K-factor of 5 burns a gallon every 5 degree days, so after 1,000 degree days the scheduler knows about 200 gallons are gone and books the truck. Good forecasting plus efficient routing turn keep-full from a promise into a reliable, profitable service. FastDragon tracks each tank's usage and forecasts drawdown, so the schedule runs on data instead of memory.
Common questions
How is a K-factor calculated?
Divide the heating degree days between two fill-ups by the gallons delivered at the second one. If 900 degree days passed and the tank took 180 gallons, the K-factor is 5. Operators recompute it after every delivery, because insulation work, a new wood stove, or different thermostat habits all shift it.
Can a customer still run out on automatic delivery?
Yes, when real usage breaks from the forecast: a relative moves in, a heat pump fails and the backup runs hard, or a cold snap outpaces the model. Most shops treat a run-out on automatic delivery as their own error and send a same-day truck, which is why conservative reserve targets are common.
Do keep-full customers pay more per gallon?
Practice varies by shop. Many distributors charge the same per-gallon price as will-call and let the program pay for itself through route density and retention. Others bundle automatic delivery with budget billing or price-cap plans, where the value shows up in the payment terms rather than the posted price.
Do you need tank monitors for a keep-full program?
No, most programs run on forecasting alone. Remote tank monitors that report actual levels are worth the hardware cost on hard-to-predict accounts: generators, rentals with changing occupants, and farms with seasonal swings. Many shops forecast the steady houses and put monitors only on the erratic tanks.