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Swapping only the air conditioner in an Oakton gas house runs $5,942 to $14,450 installed. Nearly all 1990s and 2000s detached houses here have gas.
Price range
$5,942-$14,450
8yrs @ 7.99%
$84/mo
15yrs @ 9.99%
$64/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 1,131 reviews
One of our HVAC technicians moving a new condenser up a driveway, the van behind him.
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
The same price book our estimator runs on, for a central air conditioner on its own, keeping the furnace you have. A single-stage unit on a small house sits near the bottom; a variable-speed one on a big house, near the top.
A central air conditioner alone, keeping your furnace, installed
$5,942 to $14,450
or $99/mo at 0% APR for 60 months
An air conditioner and furnace together, installed
$8,898 to $23,000
or $148/mo at 0% APR for 60 months
A heat pump in the AC’s place, installed
$8,499 to $21,650
or $142/mo at 0% APR for 60 months
Diagnostic visit, if it may be worth fixing
$99
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 cost estimator narrows it to your house. Then a tech measures, and you get the installed price in writing before anything is ordered.
With Comfort+ membership at $199 a year, the diagnostic visit is included, and half of each repair bill is banked toward replacing that system, up to $1,500.
What’s different in Oakton
Whether an Oakton air conditioner can be replaced on its own comes down to the gas line. Gas in the house means the furnace stays and only the condenser and its coil are new. No gas usually means a heat pump out back, which is a different replacement at $8,499 to $21,650. Fairfax County’s records show gas service on 93 percent of the detached houses built here in the 1990s and 2000s, and on under a third of those from the 1970s. So on a typical Oakton street the newer house is the AC-only candidate. A gas meter on the outside wall settles it.
Those gas houses are where builder condensers are aging out. Hearthstone Village, Timber Lake, Willow Creek Estates, Wheatland Farms, Fairwinds, Hannah Hills and Bridges of Oakton hold 333 houses, nearly all on gas, with a median of about 4,700 square feet above ground, and where they haven’t been replaced, the outdoor units are the builder’s, some past 25 summers. Units that old most likely hold R-22, whose production stopped in 2020, so a leak is where repairing stops making sense. A house that size usually runs two systems, and each AC is priced and replaced on its own.
Oakton’s townhouses lean electric. About six in ten have no gas on the county’s books, and Arrowood and Cherrywood Square along Borge Street, Oakton Village and Flint Hill Manor have none at all, so those outdoor units are heat pumps. Concord Village and Wyant Property are the exceptions, gas almost door to door, and a failing condenser there gets the AC-only swap. Most of those townhouses went up in the 1970s and 80s over a full basement, where the coil rides on the furnace, and the condensers stand side by side out back, so the association may have a say in size and spot.
In the garden-style condos built between 1974 and 1987, most units have no gas and cool with a heat pump whose air handler stands in a hall closet. The Oakton condominium on Oakton Terrace Road is the exception, with gas on its units by the county’s list. Out in Difficult Run, at the west end of Vale Road and Fox Mill Road, 57 percent of owners heat with gas and 6.4 percent with oil. Oil burners are outside what we work on, so for an oil house out there we’d price a switch instead. The permit comes from Fairfax County, whose A2L form rides along with any unit on the newer refrigerants.
Neighborhood by neighborhood
Census figures for the owner-occupied homes in each place, and what that usually means for the AC that’s there now.
| Place | Median home built | Most homes are | Heated with | The AC there now |
|---|---|---|---|---|
| Oakton | 1981 | single-family houses, about 4 in 10 | gas, about 6 in 10 | 1980s and 90s houses, many on their second air conditioner. |
| Difficult Run | 1982 | single-family houses, nearly all | gas, about 6 in 10 | 1980s and 90s houses, many on their second air conditioner. |
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
On a big-lot Oakton house the bedroom system cools the hardest rooms, right under the roof, and its outdoor unit is often the builder’s. If the upstairs can’t come down on a July evening while the basement system keeps up, that unit is telling you something. A $99 diagnostic sorts a tired part from a tired system before anyone prices a new one.
An air conditioner put in before 2010 most likely holds R-22, which hasn’t been made since 2020. A leak on one of those usually ends the repair road.
It’s the pump at the heart of the outdoor unit and its costliest part. Out of warranty on an older unit, the repair can come close to half the price of a new AC, the point where Goodman says replacing may be the better money.
Permits, locally
Our Virginia Class A contractor license, 2705192276, is on the side of the van.
Choosing who installs it
Questions to ask anybody who quotes you, us included.
The same Oakton street can hold a 1970s house on a heat pump and a 1990s house with a gas furnace. An AC quote only fits the second. Ask whether the tech checked for a gas meter and a furnace, because an air conditioner set where a heat pump was leaves the house heating on its backup strips all winter.
Ask how they picked the size. Copying the old nameplate repeats whatever was guessed when the house was built.
The outdoor unit and the coil on the furnace are rated as a pair. Ask whether the quote replaces both, and what happens to the line set.
A good company puts the repair price next to the replacement range and lets you choose. Already holding somebody’s big number? Take the free second opinion first.
Two of our crew going over a work order before the day's calls.
From our Google reviews
5.0 stars across 1,131 reviews. Read them on our reviews page.
Tyler from SwiftPro is very knowledgeable and professional on HVAC. Tech Edis and Rony are very professional and done good job to install AC
Where we work
Next door to Oakton: Fairfax, Vienna, Reston, Dunn Loring and Herndon.
Questions
Past thirty summers, it’s well beyond the life anyone plans on for a central air conditioner, and it most likely runs on R-22. If it still cools, enjoy it, but price the replacement now. Read the furnace’s label while you’re at it, and if that’s the builder’s too, look at the pair at $8,898 to $23,000 beside the AC on its own.
Most likely an AC on a gas furnace. The county’s books show gas almost door to door in Concord Village and Wyant Property, unlike most Oakton townhouses. Look for a gas meter outside and a furnace on the lowest level. If both are there, the outdoor unit only cools, and replacing it is the AC-only job, $5,942 to $14,450 installed, within the association’s rules for the pad.
$5,942 to $14,450 installed for a central air conditioner on its own, keeping the furnace you have; size and efficiency set where yours lands. An AC and furnace together run $8,898 to $23,000. The HVAC replacement cost estimator gives your house its own number.
It’s worth pricing. A heat pump cools exactly like an AC and also heats on mild days, so with your gas furnace it becomes dual fuel. A heat pump system runs $8,499 to $21,650 installed, and we’ll price it both ways.
Ready when you are
Call, or send the form at the top. A tech measures the house and puts the installed price in writing before anything is ordered, and if the old AC is worth fixing, 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 1,131 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.