Changing From Oil to Gas: Costs, Steps and Tradeoffs
On this page 7 sections
The first question is usually cost, and the second is whether gas actually fits the house. The answer changes a lot if you already have a gas main at the curb versus a long utility run, or if your current system is a boiler with radiators rather than a forced-air furnace.
Older oil systems can keep working fine, so the case for conversion has to be practical: lower fuel bill, less maintenance fuss, cleaner storage, or better equipment choices. If your house is a candidate for a heat pump, that may beat both oil and gas on running cost in some climates.
Changing From Oil To Gas
Changing from oil to gas means replacing the oil-fired burner in your furnace, boiler or water heater—or the entire appliance—and connecting it to a natural gas or propane line instead of a fuel-oil tank. The swap also requires new venting that meets current codes, since gas equipment exhausts differently than oil.
Oil systems store #2 heating oil in a tank—usually 275 gallons in the basement or buried outside—and an oil burner atomizes the fuel into a mist that ignites in the combustion chamber. Gas systems pull natural gas from a utility meter or propane from an above-ground or buried tank, meter it through a gas valve, and burn it in a burner designed for gaseous fuel. Venting differs because oil produces more particulate and moisture, so an oil chimney or flue won’t always work for gas without relining or replacing.
A full conversion can mean swapping just the burner if the heat exchanger and cabinet are compatible, or replacing the whole furnace or boiler when they’re not. Water heaters nearly always get replaced outright, since an oil-fired tank uses a different combustion chamber than a gas model. Combination systems—a boiler that heats both the house and domestic hot water—may need only the boiler converted if the indirect tank stays in service.
| Oil | Gas |
|---|---|
| Fuel delivery | Truck fills tank every few weeks or months |
| Burner | Atomizes liquid fuel |
| Venting | Chimney or direct vent sized for oil |
| Maintenance | Annual nozzle, filter and combustion tune-up |
Gas appliances need the room volume and ventilation the manufacturer specifies, especially for atmospheric-draft models that pull combustion air from the room. Sealed-combustion or direct-vent units bring outside air through a dedicated pipe and are easier to site in tight spaces. Every home with gas-burning equipment needs a working carbon monoxide alarm on each sleeping floor, since incomplete combustion produces CO.
What The Conversion Usually Includes
The conversion replaces the burner or the whole heating appliance, runs a gas line to it, adjusts venting to suit the new fuel, and removes or abandons the oil tank. You’ll also need a permit in most jurisdictions, and the gas utility may upgrade the meter or extend service to your property if you’re switching to natural gas for the first time.
A gas furnace or boiler still needs electricity to power ignition controls, pumps or blowers, and the thermostat. Changing fuel types means connecting gas, venting, and electrical systems so the appliance operates safely and responds correctly to temperature controls.
Homes with hot-water radiators or baseboard can usually keep the same distribution loops when you replace an oil boiler with a gas model of similar output. Forced-air systems may need duct balancing or register adjustment if the new furnace’s blower moves a different volume of air, but the ductwork itself rarely requires replacement unless it was undersized to begin with.
The oil-to-gas swap affects water heaters too. If you’re replacing the furnace or boiler, budget to replace an oil-fired water heater at the same time so one contractor handles all the gas piping in a single visit. The alternative—keeping an oil water heater after the furnace converts—leaves you buying oil for one appliance and splitting service calls between fuels.
What Changing From Oil To Gas Costs
Conversion costs vary widely, from a simple burner swap to a full system overhaul including gas main extension, appliance replacement, chimney relining and oil tank removal. The main factors are the distance to the gas line, whether your current furnace or boiler can use a gas burner or needs replacing, chimney venting requirements, and oil tank location.
Distance to the gas main drives cost faster than anything else. If natural gas runs to your street and the utility will tap the curb stop for a fixed hookup fee—often $1,000 to $2,500—you’re starting from a manageable baseline. Extending the main down a long driveway or rural road can add $30 to $70 per linear foot for trenching, pipe and labor. A 200-foot run alone can double the entire job cost before you touch the heating equipment.
| Cost bucket | Typical range | What raises it |
|---|---|---|
| Gas line hookup and meter | Costs can vary widely depending on the job’s complexity and location. | Distance over 100 ft, ledge, pavement cuts |
| New furnace or boiler | Prices fluctuate based on equipment and installation needs. | High-efficiency condensing models, complex ductwork |
| Burner replacement only | Costs depend on the specific venting and chimney work required. | Retrofit kit availability, boiler age |
| Venting and chimney work | Price varies with tank removal method and site conditions. | Stainless liner, masonry repair, sidewall vent install |
| Oil tank removal | Ranges depend on excavation and disposal requirements. | Buried tanks, soil testing, disposal fees |
| Labor and permits | Varies with furnace or boiler model and installation complexity. | Tight spaces, electrical upgrades, multiple inspections |
Venting changes quietly. Oil burners tolerate a masonry chimney shared with a water heater; gas appliances often need a dedicated stainless liner or a new sidewall vent, especially if you’re installing a high-efficiency condensing unit that exhausts cool, acidic vapor. Relining a two-story chimney runs $1,500 to $3,500. Switching from a boiler that heats radiators to a forced-air furnace that needs new ducts can add $3,000 to $8,000, turning a fuel swap into a whole-system redesign.
Tight basements, ledge that blocks trenching, and the shift from hydronic heat to forced air all raise the bill in ways a flat average hides. Get three itemized bids that spell out the gas line route, the appliance model, venting method and tank work. The live number for your house matters more than the headline range, and you’ll want it before the first cold night makes the decision urgent.
Running Cost And Comfort Compared
Switching from oil heat to electric heating or gas changes what you pay each month more than it changes how warm you feel. Gas costs less per BTU than oil in most US markets right now, and a heat pump can beat both when outdoor temperatures stay above 25°F or so. But the comfort difference is subtle: forced-air systems blow warm air whether they burn oil or gas, and how oil heating systems work with radiators feels similar to gas-fired hot water as long as boiler temperature stays consistent.
| Fuel | Cost sensitivity | Comfort feel | Best fit |
|---|---|---|---|
| Oil | Volatile; tied to crude prices | Even radiant heat with boilers, warm air with furnaces | Existing oil systems where gas isn’t available |
| Natural gas | Stable in most regions | Same delivery as oil; faster recovery in furnaces | Homes near a gas main with moderate to high heating loads |
| Heat pump | Lowest in mild weather; rises with electric rates and cold snaps | Gentler, longer cycles; may feel cooler at registers | Tight, well-insulated homes in climates above 10°F most nights |
Gas furnaces and boilers heat through a burner that ignites the fuel and a heat exchanger that transfers combustion heat to air or water. Heat pumps don’t burn anything; they move heat from outside air into your house using a refrigerant loop, which is why their efficiency drops as outdoor temperature falls. In mild weather a heat pump can deliver three or four units of heat for every unit of electricity it consumes, but below 25°F most models switch to electric resistance backup, and running cost climbs fast.
Oil-to-gas conversion improves convenience more than comfort. You’ll stop scheduling fuel deliveries and smelling oil, but room temperature and air movement stay roughly the same if you keep the same distribution system. Changing from oil heat to electric heating with a heat pump does change the kind of heat you feel: cycles run longer, supply air feels cooler at the register, and some rooms may need a second pass to stay comfortable on the coldest nights.
Can a heat pump replace an oil boiler without changing radiators? Sometimes. Heat pumps designed for hydronic systems—often called air-to-water heat pumps—can feed existing radiators or baseboard, but only if those emitters can deliver enough heat at water temperatures between 110°F and 130°F instead of the 160°F to 180°F that oil and gas boilers typically use. Oversized cast-iron radiators often work; standard baseboard usually doesn’t without adding more runs or switching to panel radiators. Changing from a fuel oil baseboard to something more energy efficient usually means either adding emitter surface area or moving to ducted mini-splits or a forced-air heat pump that doesn’t use the old piping at all.
When Electric Beats Gas Instead
Electric resistance heat—baseboard heaters, wall units, or an electric furnace—installs faster and cheaper than extending a gas main, but you’ll pay more each month unless electricity is unusually cheap where you live. Converting from oil heat to electric heating makes sense when natural gas isn’t available at the street and propane delivery isn’t practical, or when you’re replacing a boiler in a small, well-insulated home where a heat pump can handle the load.
Heat pumps move heat instead of making it, so they cost two to four times less to run than resistance baseboard for the same warmth. If your winters stay above 5°F most nights, a modern cold-climate heat pump often beats both gas conversion and straight electric resistance on lifetime cost. In milder climates—coastal British Columbia, the Pacific Northwest, parts of the Mid-Atlantic—a ducted or ductless heat pump paired with electric backup can eliminate oil without touching a gas line.
Electric boilers exist for homes with radiators or radiant floors, but a unit large enough to heat a whole house draws 15 to 30 kW. Most older homes have 100 A or 150 A service; adding a 20 or 30 kW boiler means a panel upgrade, new circuits, and sometimes a utility service increase that can run $3,000 to $8,000 before the boiler arrives. An electric boiler makes practical sense mainly in smaller hydronic systems—under 1,200 square feet—where the existing panel has room and combustion venting is impossible or banned.
Electric water heaters draw 15 to 20 A at 240 V and need their own circuit. Installing one means running new wire from the panel, and tank models set above 120°F at the thermostat raise scald risk. Any 240 V work and T&P valve connections are jobs for a licensed electrician or plumber in most jurisdictions.
If lowering your monthly fuel bill is the goal, get a heat pump estimate before choosing resistance electric. Resistance heat is simple, but it won’t save money compared to oil unless electricity is under about 10 cents per kWh and your oil price is high.
What To Do Next
Start by identifying what you have: forced-air furnace, hot-water boiler, steam boiler, or a combination unit that heats the house and domestic water. Look for the make and model on the appliance nameplate; snap a photo of it and of the oil tank.
Hire a licensed HVAC contractor for gas appliance installation and piping, a licensed electrician for any 240 V circuits or panel work, and a licensed plumber for hydronic connections or water heater T&P valve work. Most jurisdictions require those licenses for permit and inspection sign-off, and your homeowner’s insurance may deny a claim if unlicensed work causes a fire or a carbon monoxide incident.
