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Furnace and AC replacement in The Plains runs $8,898 to $23,000 installed. Here that’s usually a propane furnace, sized for 17 degree nights.
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 The Plains
Degree days measure how hard a house works to stay comfortable over a year. NOAA’s normals for the station near Warrenton, about 12 miles south, give roughly 4,685 heating degree days against about 1,018 cooling ones, more than four to one. So the furnace is sized to the house’s heat loss and the air conditioner to its heat gain, and the furnace’s blower has to move the air the new coil is rated for.
Summer still has its days. The same normals count about 21 afternoons a year at 90 or hotter, with a July average high near 85, and NOAA’s storm records for northern Fauquier include heat index readings above 115 in July 2011 and above 110 in July 2019. An air conditioner past fifteen shows its age on exactly those afternoons.
A furnace and air conditioner is the propane household’s system here. Of 589 owner homes in 20198, 134 heat with propane and 16 with utility gas; most of the rest use electricity, usually a heat pump. When both halves date from the same year, replacing them together means one County permit for the fuel-fired half, one trip into the closet where the coil sits on the furnace, and a matched pair. Rather stop heating with propane? A heat pump system runs $8,499 to $21,650 installed.
Mind where the new outdoor unit sits. NOAA logged 65 knot gusts that brought dozens of trees and wires down along Halfway Road and The Plains Road in August 2023, and a flash flood that September left roads near Marshall and The Plains blocked by standing water. Set the condenser back from the drip line of big trees, on a pad above wherever the yard holds water.
By the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
ZIP 20198 as a whole, the Town included: its own homes are too few for steady Census figures.
When it’s time
About 153 homes in 20198 went up between 2000 and 2009. A furnace and air conditioner original to one of those are at or past twenty, and when the air conditioner needs a compressor or the furnace a heat exchanger, that one repair is a big share of a new system.
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
Fauquier County does the building inspections for the Town of The Plains, and building permits are applied for with the County. Source.
Fauquier County counts swapping an electric appliance for a similar one in the same spot as an ordinary repair that needs no permit. Moving an appliance to a new spot takes one. Source.
Fauquier County wants a permit for any fuel-fired appliance, so a gas or propane furnace replacement is permit work even in the same spot. Trade permits need no plans, and usually no zoning approval. 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 to see the load calculation. Here the heating load is the bigger number by far, and a farmhouse with additions or a 1980s house with a finished basement may need a different size than it has now.
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.
David and the install team that came over were friendly, knowledgeable and professional. Happy with the install of my Trane system. Tyler was a pleasure to work work with in getting me the best price. He’s got a good thing going over there. I’m glad I went with them!
Where we work
Next door to The Plains: Broad Run, Haymarket, Rectortown, Marshall and Gainesville.
Questions
Every property in the Town of The Plains sits inside its Historic District, and improvements there need the Board’s approval. Moving the unit, or setting it where Main Street can see it, is worth a call to the Town Clerk first. The furnace’s trade permit comes from Fauquier County either way.
If the furnace is within a few years of the air conditioner’s age, usually yes: the new coil sits right on the furnace. If the furnace is much younger, keep it. A $99 diagnostic visit tells you which half is the problem, and a furnace alone runs $4,285 to $14,040 installed.
$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 The Plains 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.