Oil Furnace

How oil heat works

Unlike gas equipment, an oil furnace stores its fuel on site — typically a 275-gallon tank in the basement or outside — refilled by delivery truck. When the thermostat calls for heat, the burner's pump pressurizes oil through a fine nozzle, atomizing it into a mist that a high-voltage spark ignites inside the combustion chamber. The flame heats the heat exchanger, the blower moves house air across it, and combustion gases vent through the flue. Oil burns hot, so oil furnaces are known for delivering very warm supply air.

Oil systems need more routine attention than gas: the nozzle, oil filter, and air filter should be replaced and the burner tuned annually, because soot buildup from an out-of-tune burner insulates the heat exchanger and cuts efficiency quickly. A clogged nozzle or filter, a failed ignition transformer, a tripped primary control (the reset button), or simply running the tank dry are the classic no-heat causes.

Decisions facing oil-heated homes in the region

Plenty of homes in Southeastern Pennsylvania — especially older houses outside the gas grid — still heat with oil. Owners face recurring choices: keep the existing furnace tuned and running, replace it with a newer oil unit, or convert to a gas furnace or heat pump when the equipment or tank ages out. Tank condition matters too, since an old corroding tank is a costly leak risk. PJ MAC HVAC repairs oil furnaces along with gas furnaces, boilers, and heat pumps, and offers free estimates when replacement is on the table — so the keep-or-convert math can be run on your actual system.