In many regions of the country, oil is king. It's the most popular (read: least expensive) fuel for heating homes and other structures. Even if oil isn't as cheap today, it was when the furnace was purchased. It may be too expensive to convert to another fuel source. Other popular heating systems include the gas furnace, electric furnace, steam boiler, and hot-water boiler. Fortunately, an oil furnace is simple in operation and relatively trouble free. When it's not, it's time to fix it--or call someone who can.

How Does It Work?

An oil furnace is similar to other types of furnaces. The main difference is that heating oil fuels the burner that heats the air.

An oil furnace uses a low-grade petroleum derivative as fuel to heat air, hot water, or steam. An oil forced-air system (OFA) includes the blower and ducting to distribute the heated air throughout the house. Modern home oil systems use pressure burners. Oil is sprayed into a combustion chamber at high pressure, propelled by a blower and ignited by an electric spark. The oil burns as the mist is sprayed. These units are more efficient than older models.

What Can Go Wrong?

Oil burners are generally quite reliable. Routine maintenance is the key to avoiding expensive repairs. And there are several things you can do before calling for repair service. The burner may not run, or may run but not fire. The burner may cycle too often or it may smoke or squeal. The chimney may smoke.

Fix-It Tip

When buying replacement filters, buy enough for a few years at once so you have them on hand. And when you change the filters, write the date on the filter or on a tape stuck to the outside of the furnace so you can determine when to next replace it.