Replacing an oil furnace with a gas furnace typically costs $7,000-$16,000, with a national planning average near $11,000. The final price depends on furnace capacity, whether natural gas is already available, venting and gas-line work, and the cost of removing or closing the oil tank.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Complete oil-to-gas furnace replacement | $5,000 | $11,000 | $20,000 | Standard home, existing ductwork, typical access |
| Gas furnace and installation | $4,000 | $6,500 | $10,000 | About 80,000-100,000 BTU; equipment and labor |
| Gas service and piping | $500 | $1,800 | $5,000 | Cost rises if the meter or main is far away |
| Oil tank closure or removal | $500 | $1,500 | $5,000+ | Aboveground removal is usually less expensive |
What a Complete Oil-to-Gas Furnace Replacement Usually Costs
A straightforward conversion commonly lands between $7,000 and $16,000. That estimate assumes a typical single-family home, usable ductwork, a standard-efficiency or mid-efficiency gas furnace, normal access, and no major electrical or structural upgrades. A low-cost job may be closer to $5,000 when gas service and suitable venting already exist and the oil tank is easy to remove.
For budgeting, $11,000 is a reasonable midpoint for a complete, ordinary conversion. A high-efficiency furnace, long gas-line run, chimney or vent changes, or difficult tank work can push the total above $20,000. The price is for a furnace-based heating system; converting an oil boiler to a gas boiler involves different equipment and plumbing costs.
Furnace capacity should be selected using a heat-load calculation rather than the size of the old oil unit alone. A typical residential gas furnace may be rated around 60,000-120,000 BTU per hour, but the right size varies with insulation, climate, home layout, and air leakage. Oversizing can add equipment cost and lead to less even heating.
Assumptions: U.S. residential installation, existing forced-air ducts retained, ordinary labor access, and no major contamination or utility-main extension.
How Furnace, Gas-Line, and Tank Charges Build the Quote
Ask for a written estimate that separates equipment, installation, utility work, and oil-tank handling. Bundled estimates can hide major scope differences, particularly when one contractor includes tank removal and another prices it separately. The ranges below are common planning figures, not fixed national rates.
| Quote item | Typical price | Unit or scope | What changes the charge |
|---|---|---|---|
| Gas furnace | $2,500-$6,000 | Equipment, usually 60,000-120,000 BTU | Capacity, efficiency, brand, and staging |
| Furnace installation | $1,500-$4,000 | Removal of old unit and installation labor | Access, duct transitions, electrical changes |
| Gas piping or meter work | $500-$5,000 | Often $15-$40 per linear foot for interior piping | Distance, pipe size, utility requirements |
| Venting and chimney changes | $300-$2,500 | New flue, liner, or sidewall vent | Furnace type and existing chimney condition |
| Oil tank handling | $500-$5,000+ | Aboveground removal to underground closure | Tank location, permits, soil testing, contamination |
| Permit and inspection | $100-$700 | Local building or mechanical permits | Municipality and work scope |
Some quotes include disposal of the oil furnace and tank; others list those services separately. Confirm whether the estimate covers refrigerant or condensate drainage changes, thermostat wiring, gas shutoff valves, start-up testing, and inspection fees.
Compare the same scope line by line, not just the final total. A $9,000 bid excluding tank removal and gas-line work may cost more than a $12,000 bid that includes both.
Which BTU Size, Gas Distance, and Tank Type Raise the Price?
Three details commonly shift the quote by thousands of dollars: furnace capacity, distance from the gas meter, and oil-tank location. A basic furnace may fit a compact, well-insulated home, while a large or leaky home in a cold climate may need a higher-capacity unit. Moving from a 60,000-BTU model to a 100,000-BTU model can add roughly $500-$1,500 for equipment, though installation and efficiency choices also matter.
Gas piping is often more affordable when the meter is near the furnace. A short 10-20-foot run may cost about $500-$1,200, while a 50-foot route with difficult access can reach $1,500-$3,000 or more. Utility-company charges to extend a service line or upgrade a meter are separate in some areas and may add $1,000-$5,000 or more.
Tank work varies substantially. An accessible basement or garage tank may cost around $500-$1,500 to pump out and remove. An aboveground tank in a cramped location can cost more if it must be cut apart. An underground tank often costs $1,500-$5,000 for closure or removal; soil testing and petroleum cleanup can raise the bill beyond $10,000 if a leak is found.
Venting is another equipment-specific issue. A high-efficiency condensing furnace may use PVC venting and a condensate drain, while a non-condensing model may require a suitable chimney liner or other approved flue. A liner can cost about $1,000-$2,500. Chimney condition and local code determine whether existing venting can stay.
Get the tank type and gas-line route inspected before treating a quote as final. A contractor may revise the estimate after discovering a buried tank, undersized gas piping, unsafe wiring, or a chimney that cannot vent the selected furnace.
Regional Labor Rates Change the Total Conversion Price
Local labor, utility procedures, permit fees, and weather-driven demand affect the installed price. In lower-cost markets with established gas service, a standard project may fall near $6,000-$12,000. In many suburban and urban areas, the same scope may run $8,000-$16,000. High-cost metros, remote locations, or regions with complex tank rules can reach $12,000-$22,000 or more.
These are broad comparisons, not state-by-state guarantees. Dense cities may charge more for labor and access, while rural homes may face higher travel costs or a long service-line extension. In places where oil heating is common, local contractors may be familiar with tank removal but gas service may be less available.
For example, a household in the Northeast with an underground tank may spend more on tank closure and environmental review than a household in a gas-served Midwestern suburb with an aboveground tank. In either region, a utility contribution toward a new gas connection can lower the homeowner’s out-of-pocket cost, but programs and eligibility vary.
Use local written estimates for regional budgeting. National averages cannot account for a utility’s extension charge, a city’s permit rules, or the cost of working around a buried tank.
Three Sample Quotes for Different Furnace Conversion Scopes
These examples show how scope affects a complete price. They assume existing ducts remain and exclude major environmental cleanup. Labor totals vary by market and crew, so the examples are illustrations rather than guaranteed bids.
| Project example | Scope and labor | Estimated total |
|---|---|---|
| Gas-ready home | 80,000-BTU furnace, short gas connection, simple aboveground tank removal, 12-16 labor hours | $6,500-$9,000 |
| Typical conversion | 80,000-100,000-BTU furnace, 25-foot gas run, vent updates, tank removal, 18-24 labor hours | $9,000-$14,000 |
| Complex tank and vent work | 100,000-120,000-BTU furnace, longer piping, chimney liner, underground tank closure, 24-36 labor hours | $15,000-$23,000+ |
In the typical example, the furnace and installation might account for $5,000-$8,000, piping and venting $1,500-$3,500, and tank work and permits $1,000-$2,500. The high-complexity example can exceed that range if the tank leaks or the gas utility must extend its service line.
Check that each bid describes furnace capacity, venting, tank disposition, and utility work. Those specifications make the examples useful for comparison and help expose omitted charges.
How Long Installation Takes and When Labor Costs More
A standard replacement often takes one to two days of on-site work. A straightforward furnace change with an existing gas connection may need 8-16 labor hours. A conversion requiring new piping, a chimney liner, electrical corrections, and tank removal may take 16-32 hours spread over two or three days. Underground tank work can add scheduling time even when it does not extend furnace installation itself.
Contractor labor is commonly priced as part of the installed job, but a service or diagnostic visit may cost $75-$200 if it is billed separately. Heating contractors can be busiest during cold spells and early winter, when urgent replacement work may limit scheduling flexibility. A rush or after-hours installation can add several hundred dollars, depending on the market.
Time on site is not the only schedule constraint. Gas utilities may need to inspect or activate a new meter before the furnace can operate. Local officials may also require a permit inspection. Confirm who arranges utility appointments and whether the old oil system will remain available until the gas furnace passes testing.
Plan the conversion before the heating season if the old furnace is still safe to operate. Advance scheduling gives more time to coordinate tank work, permits, and gas service without paying for emergency labor or temporary heat.
Which Permits and Utility Checks Belong in the Estimate?
Gas-furnace installation generally requires a mechanical or building permit, and new gas piping may require a separate permit or inspection. Fees commonly range from $100-$700, but local rules vary. Ask the contractor to identify the permit holder, included fees, inspection responsibilities, and any required pressure test or combustion-safety check.
The gas utility may inspect or replace a meter, verify service capacity, or require a service-line extension. Utility work can be free, subsidized, or billed separately depending on the provider and project. Get the utility’s written terms before approving equipment installation, especially if the home does not already have natural gas.
Tank closure rules differ by state and municipality. Some jurisdictions require licensed tank contractors, documented pumping, soil sampling, or notice to local authorities. A buried tank can trigger additional requirements even when no leak is apparent. Keep closure paperwork and test results with the home’s records.
Some utilities and state programs offer rebates for qualifying high-efficiency equipment, while federal or local incentives can change over time. Eligibility may depend on income, equipment efficiency, installation date, and whether the home meets program rules. Treat incentives as a possible reduction only after confirming current requirements; do not subtract them from a quote based on an assumption.
Separate contractor charges from utility and government charges. That distinction makes it clearer whether a low estimate omits an inspection, meter upgrade, tank report, or other required work.
Ways to Lower the Price Without Cutting Necessary Safety Work
Keep the project scope focused on safe, code-compliant heating. Reuse sound ductwork, registers, and thermostats when the contractor confirms they are compatible. Avoid paying to replace ducts solely because the furnace is changing fuel; repairs or sealing may be enough if the system is in usable condition.
Compare standard-efficiency and high-efficiency furnace options using both installed price and venting requirements. A high-efficiency unit can cost more upfront and may need new vent and condensate piping. Whether the extra expense pays back depends on fuel prices, annual usage, climate, equipment performance, and the length of time the household expects to stay in the home.
Request separate prices for tank pumping, tank removal or closure, gas piping, venting, and any electrical upgrades. Obtain at least three bids with the same capacity assumptions and tank scope. Ask whether the contractor has verified the gas route and tank location in person rather than relying only on a phone estimate.
Do not defer required tank work, gas pressure testing, combustion setup, or permits to reduce the apparent price. Instead, ask whether an aboveground tank can be removed at the same time as the furnace, whether the utility offers a connection allowance, and whether nonurgent duct or thermostat upgrades can be handled separately.
The best savings usually come from avoiding duplicated work and comparing complete scopes. A modestly priced furnace is not a bargain if the quote leaves out required venting, tank disposal, permits, or gas service.