Furnace replacement in Triangle.
A new gas furnace in Triangle runs $4,285 to $14,040 installed, keeping your AC. Three owners in four here heat with gas, many on a furnace from the 2000s.
- Installed price in writing
- Sized to the house, not the old nameplate
- Dedicated HVAC team
Get your furnace priced in writing
Triangle furnaces come from two eras: the 1950s plats and the 2004 subdivisions.
Natural gas heats 1,574 of Triangle’s 2,089 owner homes, close to three in four, and propane only about a dozen, so a furnace swap here is nearly always gas for gas. The owner homes skew new: 915 date from 2000 through 2009 alone, and County plats record Kerill Woods in 2001 and Cramers Ridge, Lionsfield Valley and Garrison Woods in 2004. A furnace that came with one of those houses is near twenty winters, the far end of the usual run.
The older streets go back much further. Carborough Heights was platted in 1946, Mockingbird Heights and the first Graham Park section in 1950, Amidon in 1955, and about one Triangle home in six predates 1960. A furnace there may still vent up a masonry chimney beside the gas water heater. A high-efficiency one leaves that chimney for a plastic pipe out the side wall, and how the water heater then vents by itself belongs in the written quote.
Winters near the Potomac run milder than inland. NOAA’s 1991 to 2020 normals for the Quantico Marine Corps Air Station, 3.8 miles away on the shoreline, come to about 4,000 heating degree days a year and a January average low of 28; Dulles Airport’s, about 4,600 and 25. Mild still has hard weeks: late January 2026 brought Extreme Cold Warnings and wind chills of zero to ten below from the Piedmont to I-95. A furnace that came out of that stretch noisy, short cycling or tripping its safeties is worth pricing before next winter.
Your permit office depends on a line the mail doesn’t show. Nearly all of 22172 is Prince William County’s, which counts every gas furnace swap as permit work. The main exception is Port O’Dumfries, townhouses on Masthead Trail, Port Hope Point and Tavern Way with Triangle addresses but inside the Town of Dumfries, whose own building department issues the permit. Built from the mid-1970s to the late 1980s, they’re likely on a second or third furnace. On Marine Corps Base Quantico next door, family housing belongs to Liberty Military Housing, which maintains it, so on-post residents call their housing office.
Triangle houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
Triangle
- Median home built2003 Census
- Built before 1980about 4 in 10 Census
- Built since 2000about 5 in 10 Census
- Most homes aresingle-family houses, about 6 in 10 Census
- Heated withgas, about 8 in 10 Census
- Rentedabout 4 in 10 Census
- A lot of furnaces here are the builder’s originals, coming up on twenty years.
- 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.
What a new furnace costs in Triangle.
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 Triangle.
The outdoor unit is newer than the furnace
If the condenser out back has been swapped since the house was built and the furnace hasn’t, a furnace-only job keeps the newer half. Ask how the new blower gets matched to the coil on top.
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.
Who signs off on a new furnace in Triangle.
Prince William County
Prince William County requires a permit to replace a gas or propane furnace or a gas appliance such as a water heater, even like for like. Replacing an electric water heater with one the same size in the same spot needs no permit. Source.
How to pick the best furnace replacement company in Triangle.
Questions to ask anybody who quotes you, us included.
Do they know which office your street files with?
A Triangle address can sit in Prince William County or inside the Town of Dumfries. Ask the company which office it’s filing the furnace permit with, and how it checked.
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.
Moises and Oscar did a superlative job doing a custom installation of a new HVAC unit in a tight basement space. And they then took the time to go over system operation. Top tier job and service in all respects!
5.0 stars across 884 Google reviews. Read them on our reviews page.
Furnace replacement questions from Triangle.
When’s the best time to replace a furnace in Triangle?
Between the last frost and the first. At the Quantico station the median last freezing night of spring is March 28 and the median first one of fall is November 8, so from April through October the house won’t miss its heat while the old furnace comes out. Planned then, it’s priced on your schedule, not January’s.
How much does a new furnace cost in Triangle?
$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 Triangle.
More from SwiftPro in Triangle
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 Triangle 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.