Should an Oil Furnace Be on While Refilling?

Oil Furnace Tank

• The tank for your oil furnace is usually located in your backyard, a short distance from your home. It might sit above ground, although large tanks are sometimes buried underground to prevent them from taking up too much of your backyard space or from being an eyesore. The tanks are not intended to be accessed by homeowners. Instead, they are filled and refilled by a professional dispenser who delivers the oil to your home. You can place an order for however much oil you need, and the company will bring it to you.

Pros

• Over time, your oil tank can develop sediment and sludge along its bottom caused by impurities in the oil. Filters on your oil furnace system prevent these issues from being a problem, but you can take other measures to help keep sediment out of your furnace. Turning off the furnace when the tank is being refilled will allow any contaminants in the new oil to settle to the bottom of the tank. Leave the furnace off for an hour or so after the refill process is over, and then turn it back on.

Cons

• When you turn off your furnace, your home does not receive heat. In the beginning of winter, this might not be a major issue, but if the weather is very cold, your home could soon be uncomfortable. You also will need to run the furnace longer after it is refilled to warm your home up, burning more oil than you would otherwise. If refilling your oil tank brings up a lot of sediment, it is a sign you are letting the oil level get too low before refilling the tank.

Considerations

• The server who delivers your oil might have a preference regarding whether the furnace should be turned on or off during the refilling process. If you keep your oil tank at least one-third full throughout the winter, it is unlikely that refilling it will disturb the sludge on the bottom. Never letting the tank become nearly empty also prevents a crisis if there is a major snowfall that prevents the supply trucks from reaching your home for a week or two.