Furnace replacement in Leesburg.
Replacing just the furnace in Leesburg runs $4,285 to $14,040 installed, with your air conditioner kept. Two in three owners in town heat with gas.
- Installed price in writing
- Sized to the house, not the old nameplate
- Dedicated HVAC team
Get your furnace priced in writing
In Leesburg the County permits the furnace, and downtown the Town watches the vent.
Gas heats about two owner homes in three inside the town limits and about eight in ten out in Lansdowne. Four homes in ten in town went up between 1980 and 1999, so a builder’s furnace in one of them would be more than twenty-five by now. Most have likely given way to a second furnace bought on its own schedule, so the furnace and the outdoor unit often show different years on their labels. When the outdoor unit is the younger half, replacing the furnace alone is the sensible job.
Loudoun County issues the gas permit for that swap on both sides of the town line. Since October 2025, a furnace replaced at the same input rating, in the same spot, skips plan review. Go up a size because the basement got finished, or move the furnace out of a townhouse attic into a closet, and drawings go to the County first. Measure the house before you pick the size.
Downtown, the Old and Historic District brings the Town into it. Its design guidelines ask owners to keep their chimneys and to add roof vents only where they’re inconspicuous, on a side or rear slope. A high-efficiency furnace exhausts through plastic pipe in a wall or the roof, and the Town wants a Certificate of Appropriateness for any exterior alteration in the district. Preservation staff approve some in the office; others go to the Board of Architectural Review, a public hearing with a sign on the house 15 days ahead and letters to the neighbors.
Lansdowne’s median owner home dates to 2005, so a furnace that came with the house is near twenty, the end of the usual run. Close to four in ten homes there are condos, where the furnace usually sits in a closet and the doorway decides which cabinet fits.
The furnaces across Leesburg, place by place.
Census figures for the owner-occupied homes in each place, and what that usually means for the furnace that’s there now.
| Place | Median home built | Most homes are | Heated with | The furnace there now |
|---|---|---|---|---|
| Leesburg | 1996 | single-family houses, about 4 in 10 | gas, about 7 in 10 | 1980s and 90s houses, many on their second furnace. |
| Lansdowne | 2005 | condo and apartment buildings, about 4 in 10 | gas, about 8 in 10 | Builder gas furnaces, many now near twenty years old. |
Leesburg houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
The Town of Leesburg
Inside the town limits: the Old and Historic District downtown, Exeter and Carrvale inside the bypass, Potomac Station and Edwards Landing outside it.
- Median home built1996 Census
- Built before 1980about 2 in 10 Census
- Built since 2000about 4 in 10 Census
- Most homes aresingle-family houses, about 4 in 10 Census
- Heated withgas, about 7 in 10 Census
- Rentedabout 3 in 10 Census
- Most heat here is gas, so the usual job is gas furnace for gas furnace, and the real choice is how efficient the new one should be.
The Loudoun County side
Lansdowne only. It’s the one Census place outside the town limits, so the farms and lots beyond it aren’t in these figures.
- Median home built2005 Census
- Built before 1980hardly any Census
- Built since 2000about 9 in 10 Census
- Most homes arecondo and apartment buildings, about 4 in 10 Census
- Heated withgas, about 8 in 10 Census
- Rentedabout 3 in 10 Census
- A lot of furnaces here are the builder’s originals, coming up on twenty years.
What a new furnace costs in Leesburg.
The same price book our estimator runs on, for a gas furnace on its own, 2 to 5 tons, keeping the air conditioner you have. A single-stage furnace in a small house sits near the bottom; a modulating one in a big house, near the top.
- A gas furnace alone, keeping your air conditioner, installed$4,285 to $14,040
- A furnace and air conditioner together, installed$8,898 to $23,000
- Repair diagnostic visit, if it may be worth fixing$99
The HVAC replacement cost estimator narrows it to your house. Then a tech measures, and you get the installed price in writing, at no charge, before anything is ordered.
Natural gas or propane, in a house, a townhouse or a condo, we replace them all. Oil furnaces we don’t.
When a new furnace makes sense in Leesburg.
An old downtown furnace still lights, for now
Settle the vent route while it still runs. A new pipe through a wall or the roof of a downtown house waits on the Town’s review, and an application that misses the Board’s deadline rolls to the next month’s meeting.
It’s still the builder’s furnace
A house from the 2000s often runs the furnace it was built with. Around twenty years, inducer motors and control boards start to go, one after another.
The heat exchanger is cracked
It’s the wall that keeps the burner’s exhaust out of the air the furnace blows through the house. Nobody patches one; a crack ends the repair conversation.
How to pick the best furnace replacement company in Leesburg.
Questions to ask anybody who quotes you, us included.
Did they show you, from outside, where the new vent leaves the house?
Downtown, that route decides whether the Town reviews the job; on any house, it decides where the exhaust and condensate go. A quote that names the furnace but not the vent left out the hard part.
Did they size it to your house?
Ask how they picked the size. Copying the old nameplate repeats whatever was guessed when the house was built.
Did they check the air conditioner you’re keeping?
A new furnace has to work with the coil and the outdoor unit already there. Ask whether they looked at both before quoting a furnace on its own.
Will they tell you if it’s worth fixing?
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.
What our customers say.
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Furnace replacement questions from Leesburg.
Does the Town of Leesburg issue the permit for a new furnace?
No. Loudoun County’s Department of Building and Development issues building and trade permits inside the town limits, as it does in Lansdowne. The Town’s part is the outside: in the Old and Historic District, a new vent is an exterior alteration and needs its Certificate of Appropriateness.
My Lansdowne furnace came with the house. Is it time?
Time to price one. If it still heats, a $99 diagnostic visit says whether it’s worth another winter. If it’s failing, the HVAC replacement cost estimator gives your range, and a newer outdoor unit keeps the job to the furnace alone.
How much does a new furnace cost in Leesburg?
$4,285 to $14,040 installed for a gas furnace on its own, keeping the air conditioner you have; size and efficiency set where yours lands. A furnace and air conditioner together run $8,898 to $23,000. The HVAC replacement cost estimator gives your house its own number.
Should I repair it or replace it?
Fix the small parts on almost any furnace. Past fifteen years, with a repair over a third of the price of a new one, replacing usually wins. Not sure which you’re looking at? The diagnostic visit is $99, and the tech prices the repair before starting it.
More from SwiftPro in Leesburg.
More from SwiftPro in Leesburg
The range first, then your number.
Call, or book online and pick a window. A tech measures the house and puts the installed price in writing before anything is ordered, and if the old furnace is worth fixing, you’ll hear that first.
SwiftPro Heating, Cooling & Plumbing is a licensed, BBB Accredited (A rating), independently owned heating, cooling and plumbing company in Chantilly, serving Leesburg and the rest of Northern Virginia. Virginia contractor license #2705192276. 5.0 stars across 884 Google reviews. SwiftPro maintains a dedicated HVAC team and a dedicated plumbing team.
SwiftPro Heating, Cooling & Plumbing, 4230 Lafayette Center Dr, Suite N, Chantilly, VA 20151, (703) 997-9757. Book online, read our reviews, or see every town we serve.