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Furnace and AC replacement in Oakton runs $8,898 to $23,000 installed. The typical house here dates from 1984, so the second pair is the one wearing out.
Price range
$8,898-$23,000
8yrs @ 7.99%
$126/mo
15yrs @ 9.99%
$96/mo
Monthly figures on the starting price, the whole price financed, on approved credit. The lender sets the final terms. How financing works
Get your price in writing
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5.0 stars across 1,132 reviews
One of our technicians with a new Trane outdoor unit he just installed beside a Northern Virginia house.
Licensed and insuredVirginia Class A contractor #2705192276
24/7 emergency serviceOften same-day, and we will tell you honestly when we can get there.
Our own HVAC installersA dedicated heating and cooling team, separate from our plumbers
Price in writing firstYou see every option priced before anything is ordered
What it costs
$8,898 to $23,000 installed for a furnace and air conditioner replaced together, 2 to 5 ton, from the same price book as our estimator. Where you land depends on the size of the house, the efficiency you pick, and what the ductwork and venting need.
Furnace and AC together, installed
$8,898 to $23,000
or $148/mo at 0% APR for 60 months
Furnace alone, keeping your AC
$4,285 to $14,040
or $71/mo at 0% APR for 60 months
Heat pump system instead
$8,499 to $21,650
or $142/mo at 0% APR for 60 months
Monthly figures: 60mo @ 0% APR on each starting price, the whole price financed, on approved credit. Longer plans lower the payment and cost more in total. The lender sets the final terms. How financing works
The HVAC replacement estimator gives your house its own number. Then we measure, and the price is in writing before anything is ordered.
Two years of labor come with every install. Monthly plans are on our financing page.
What’s different in Oakton
Half of ZIP 22124’s owner homes were built before 1984 and half after. Nearly half of all Oakton homes date from 1980 through 1999, a little under four in ten from before that, and fewer than two in ten from 2000 on. Heating and cooling equipment generally gives fifteen to twenty years, so a builder’s pair from the 1980s came out somewhere near 2000 to 2005, and the pair that replaced it is past twenty itself now.
A pair from those years most likely holds R-22 in both the condenser and the indoor coil. A new outdoor unit runs on today’s refrigerants and needs a coil made for them, so replacing the air conditioner alone still opens the furnace closet. When the furnace below is the same vintage, replacing the two together means the closet gets opened once and the county inspects once.
At the west end of Vale Road and Fox Mill Road, the Census counts a separate area, Difficult Run, where almost all the homes are detached houses and close to nine in ten predate 2000. Houses that size frequently run a pair of systems, a downstairs one and an upstairs one, and the two seldom went in the same year. Their labels decide which goes first, and replacing one now and the other in a few years is a perfectly good plan.
In the older single-family streets between Blake Lane and Chain Bridge Road, Grays Oakton among them, a house built before 1980 may be on its third pair, still pushing air through the ductwork designed for the original. There the ducts get measured before anybody picks a size. In the townhouse clusters off Jermantown Road, the outdoor units sit side by side out back, and the association may have a say in where and how big the new one can be.
Neighborhood by neighborhood
Census figures for the owner-occupied homes in each place, and what that usually means for a replacement.
| Place | Median home built | Most homes are | Heated with | What the system usually is |
|---|---|---|---|---|
| Oakton | 1981 | single-family houses, about 4 in 10 | gas, about 6 in 10 | 1980s and 90s houses, most on their second furnace and AC. |
| Difficult Run | 1982 | single-family houses, nearly all | gas, about 6 in 10 | 1980s and 90s houses, most on their second furnace and AC. |
By the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
ZIP 22124 as a whole: every Oakton address. The Oakton Census place in the table also takes in streets with Vienna and Fairfax mail.
When it’s time
Find the year on the furnace’s rating plate and on the outdoor unit’s label. When they match, the two went in together and have aged side by side. A dead compressor on one is your cue to get a number on the other, not a reason to set a new outdoor unit on a tired furnace.
Where a lot of homes heat with electricity, the indoor half is often an air handler, and the like-for-like swap is a heat pump system, $8,499 to $21,650 installed.
The label on its side names the refrigerant. R-22 hasn’t been made or imported in the US since 2020, so a leak gets expensive. Replace it on your schedule, not in July.
Permits and sign-offs
Fairfax County lists replacing a heating or cooling system as mechanical permit work. Source.
Fairfax County requires a permit to replace any gas appliance, even like for like: a gas water heater, furnace or boiler. Replacing a fuel-burning appliance also needs a chimney vent certification. Source.
Fairfax County asks for an A2L refrigeration system certification with the permit for any heat pump or air conditioner that runs on the newer A2L refrigerants. Source.
Our Virginia Class A contractor license, 2705192276, is on the side of the van.
Choosing who installs it
Ask every company that quotes the job, us included.
Ask for a separate line per system, with its age and condition written beside it. Then you can do both now or one at a time, instead of weighing one lump figure for the whole house.
The old size is a guess somebody made years ago. Ask whether they measure the house and check the ductwork first. Too big short cycles; too small runs all afternoon in August.
Furnace, outdoor unit, matching coil, refrigerant lines, thermostat, permit and hauling the old one away. If it isn’t on the paper, ask.
Our free second opinion looks at the system you were quoted on and tells you what it actually needs, with our price if you want it.
Two of our crew going over a work order before the day's calls.
The system we put in first
Built to take a beating. Put in by our crew.
Heat lamps, snow and rain on one outdoor unit: that’s Trane’s own film. We’re a Trane Comfort Specialist, on Trane’s own dealer locator, and when you pick a Trane, our crew puts it in.
Films: Trane’s own.
From our Google reviews
5.0 stars across 1,132 reviews. Read them on our reviews page.
Hard working crew that removed old system and installed new system in a professional manner.
Where we work
Next door to Oakton: Fairfax, Vienna, Reston, Dunn Loring and Herndon.
Questions
Where there’s a gas furnace, a heat pump can take the air conditioner’s place, and the new furnace covers the coldest nights. Washington Gas pays its largest dual fuel rebate for exactly that job: a qualifying heat pump replacing a central air conditioner, installed with a new 95 percent furnace. Our dual fuel guide has the terms.
$8,898 to $23,000 installed for the pair, by size and efficiency. A furnace alone, keeping your AC, is $4,285 to $14,040. The HVAC replacement estimator gives your house its own number.
No. If the AC is young and only the furnace failed, replace the furnace. If they’re the same age, do both: a new outdoor unit needs a matched coil, and one built for the old refrigerant isn’t rated for the new one.
Ready when you are
Call, send the form at the top, or take the HVAC replacement estimator first. We measure before we quote, and if a repair makes more sense than a new system, you’ll hear that first.
SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
Virginia Class A contractor license #2705192276
SwiftPro Heating, Cooling & Plumbing is a licensed, BBB Accredited (A rating), independently owned heating, cooling and plumbing company in Chantilly, serving Oakton and the rest of Northern Virginia. Virginia contractor license #2705192276. 5.0 stars across 1,132 reviews on Google, Angi, Yelp, the BBB and Facebook. SwiftPro maintains a dedicated HVAC team and a dedicated plumbing team.
From SwiftPro Heating, Cooling & Plumbing in Chantilly. Housing figures are the Census Bureau’s American Community Survey, 2020 to 2024, for each place named; permit, water and sewer facts link to each office’s own page and were checked in September and October 2026.