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Most furnace installations finish in a single day, usually 4 to 10 hours, and a full gas furnace replacement costs around $3,800 to $10,000 installed. Your final price depends on the furnace type, efficiency rating, and the condition of your ductwork. A straightforward swap with good existing ducts sits on the faster, cheaper end, while new venting or ductwork pushes both time and cost higher.
Planning a furnace installation in Stilwell or anywhere across our Oklahoma and Arkansas service area? Knowing the timeline and the real numbers ahead of time helps you budget with confidence and avoid surprises on install day. Below you’ll find clear cost ranges, a step-by-step look at what happens during the job, and the factors that move your price.
Key Takeaways
- Most furnace installs are completed in one day, typically 4 to 10 hours
- A full gas furnace replacement runs about $3,800 to $10,000 installed, with most homeowners spending near $4,800
- Furnace type, efficiency rating, and ductwork condition are the biggest cost drivers
- A new federal rule requires most new residential gas furnaces to hit 95% AFUE starting in late 2028
- The best time to install is during warmer months when contractor demand is lower
How Much Does Furnace Installation Cost?
A new furnace installation usually costs between $4,000 and $8,000, though the full range stretches from about $1,600 for a basic electric swap to over $12,000 for high-efficiency systems with major changes. According to HomeAdvisor data, the average furnace replacement lands around $4,803, with a normal range of $2,824 to $6,883.
The “price of the box” is only part of the bill. The rest comes from labor, permits, ductwork, gas or electrical work, and safe removal of your old unit.
Cost by Furnace Type
The fuel type your furnace uses has a big effect on the total price. Here’s how the three common types compare:
| Furnace Type | Installed Cost Range |
| Electric | $2,000 to $7,000 |
| Natural Gas | $3,800 to $10,000 |
| Oil | $6,750 to $10,000 |
Electric furnaces are the most budget-friendly to install but can cost more to run in cold winters. Natural gas sits in the middle and is the most common choice for our region. If you’re weighing your options, our gas vs electric furnace comparison breaks down the long-term costs side by side.
What Drives the Price Up or Down
Several details decide where your quote lands within these ranges. The size of your home matters, since Angi reports a 1,600 to 2,000-square-foot house averages about $7,000 for a gas furnace replacement.
Other factors that move your price:
- Efficiency rating of the unit you choose
- Ductwork condition, since minor sealing runs $300 to $1,500 and full replacement can hit $5,600 or more
- Gas line or electrical work if new runs are needed
- Add-ons like a smart thermostat, humidifier, or zoning
Flexible payment options make a new system easier to manage. Our HVAC financing plans help spread the cost without delaying the comfort your home needs.
Furnace Installation Timeline: How Long Does it Take?
Most furnace installations take just one day, typically 4 to 10 hours, depending on the furnace type, ductwork condition, and how easy your installation site is to reach. A simple like-for-like replacement in a home with good ductwork falls on the shorter end. Lennox confirms that most homeowners can expect their furnace to be replaced and running again in a single day.
So while the idea of losing heat for days sounds stressful, the reality is far easier. Experienced teams schedule the work so your home is warm again by the end of the day.
Typical One-Day Timeline
For a standard replacement, HVAC.com notes the complete process averages 4 to 8 hours. It helps to set aside a full day so you’re home when the technician arrives and available to answer any questions.
A basic swap with healthy ductwork can sometimes wrap up in just 4 to 5 hours. The work moves quickly when your existing setup is sound and the install location is accessible.
What Can Extend the Job
Some situations stretch the timeline beyond a single day. The most common reasons a job runs longer:
- Ductwork repairs or resizing discovered during the job
- Switching fuel types, such as electric to gas, which needs new lines
- High-efficiency models that require special venting and drainage
- First-time installs with no existing system, which can take 1 to 3 days
A first-time installation is the largest project. It means running new ductwork, installing fresh gas and electrical lines, and cutting vents from scratch.
What Happens During a Furnace Installation?
A professional furnace installation follows a clear, step-by-step sequence. Knowing each stage helps you understand what your technician is doing and why the job takes the time it does.
- Home assessment and sizing. The technician measures your home and reviews your current system to confirm the right furnace size and model. Proper sizing gives you better efficiency and comfort.
- Site preparation. The work area is cleared, and your ductwork and venting are inspected. Any needed adjustments happen before the new unit goes in.
- Old unit removal. The existing furnace is disconnected and safely hauled away.
- New furnace placement. The new system is set in position and secured.
- Connections. Ductwork is connected and sealed, then electrical wiring and gas connections are made with care.
- Testing and commissioning. The technician tests the system, calibrates settings, and confirms safe, reliable operation before finishing.
This final testing step is the most important. It protects your family’s comfort and safety through the changing seasons.
What Factors Affect Your Total Cost?
Beyond furnace type, two technical details have the biggest pull on your final bill: the efficiency rating and the state of your ductwork and venting. Understanding both helps you read your quote and ask the right questions.
How Does Efficiency Rating Affect Cost?
A furnace’s efficiency is measured by its AFUE, or Annual Fuel Utilization Efficiency. A higher AFUE means more of your fuel turns into heat instead of waste, which lowers your monthly bills but raises the upfront price.
Standard 80% AFUE models cost less to buy but waste more fuel. High-efficiency models in the 90% to 95% range cost more up front and pay you back over time, especially during cold Oklahoma and Arkansas winters. There’s also a timing factor to consider. Filterbuy reports that a finalized federal rule will require most new residential gas furnaces to be at least 95% AFUE starting in late 2028. If you have an older 80% unit, it’s worth pricing a replacement now so you know your options.
Does Ductwork Condition Change the Price?
Yes, the shape of your ductwork can swing your total cost in either direction. Good, properly sized ducts let the install move fast and keep labor low. Damaged or leaky ducts add both time and money.
Minor duct sealing and repairs cost $300 to $1,500 and often improve efficiency on their own. If your ducts are beyond saving, full replacement can run $1,400 to $5,600 or more. The same sizing care that matters for furnaces applies to your whole system, much like getting proper sizing right on a cooling unit.
Should You Repair or Replace Your Furnace?
Deciding between a repair and a full replacement comes down to age, repair frequency, and cost. Most furnaces last 15 to 25 years and tend to break down more often after the 15-year mark. If yours is nearing 20 years and needing frequent fixes, replacement usually makes more sense.
A few signs that point toward replacement:
- Repair costs creeping toward half the price of a new unit
- Rising energy bills despite normal use
- Uneven heating, strange noises, or rust on key parts
A new system brings lower repair costs and steadier comfort for another 15 to 25 years. If you’re still weighing the choice, our guide on repair vs replacement helps you compare based on your system’s age and condition.
When Is the Best Time to Install a Furnace?
The best time to install a furnace is often during the warmer months, when contractor demand is lower and you have time to make a careful choice. U.S. News notes that off-peak timing lets you avoid the rush and compare your options without pressure.
Planning ahead also means avoiding an emergency install during the first cold snap. Off-peak scheduling can even lower your labor cost. A little forethought keeps the whole project calm and budget-friendly.
Ready for Reliable Heat This Winter?
A new furnace is a real investment, but the process doesn’t have to be stressful. Most installs finish in one day, and knowing your cost range ahead of time puts you in control. The right furnace, sized correctly and installed by trusted hands, keeps your home warm and your bills steady for years.
At Girdner Heat and Air, we serve homeowners across Stilwell and the surrounding Oklahoma and Arkansas communities with honest pricing and dependable furnace installation. We’ll help you find the right system for your home and budget, with no pressure and no surprises.
Ready to stay comfortable this winter? Give us a call or get in touch for a free estimate today.
