Furnace and AC replacement in Great Falls.
Furnace and AC replacement in Great Falls runs $8,898 to $23,000 installed per system, and big houses here often have two. The estimator quiz prices yours.
- Your price range up front
- Sized to the house, not the old label
- Dedicated HVAC team
Get your new system priced
Forty-year-old houses, two systems apiece, and pairs that wear out together.
The typical owner-occupied house in Great Falls was built in 1986, by the Census count. Its first furnace and air conditioner went in together, and in many houses the second pair did too, sometime in the 2000s. That pair is now around twenty on both halves, and its outdoor unit very likely runs on R-22. When one half of a pair like that gives out, the other is seldom far behind.
Size changes the job by neighborhood. In Lexington Estates and Hickory Creek the middle house went up in 1977 with about 2,000 to 2,400 square feet above the basement, and one system may carry all of it. In Great Falls West and Hickory Vale Farm, built around 1993 and 1994, the middle house has about 4,500 square feet above ground, and two or three systems is normal.
With more than one system, they rarely reach the end together. The one serving the main floor and basement tends to log the most hours; the attic system over the bedrooms works hardest in July. Each pair is judged on its own age and repair history, and each goes through the replacement estimator separately. If two are the same age and one has failed, pricing both lets you plan the work as one stretch.
Size for the house as it stands now. More than eight in ten Great Falls houses have a basement recreation room on the county’s books, and about one in five has a remodel year of 2000 or later. A lower level finished after the fact was often hung off the main floor’s ducts, so a replacement is the moment to measure and size each system for the floors it actually serves.
Great Falls houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
Great Falls
- Median home built1986 Census
- Built before 1980about 4 in 10 Census
- Built since 2000about 2 in 10 Census
- Most homes aresingle-family houses, nearly all Census
- Heated withgas, about 5 in 10 Census
- Rentedhardly any Census
- A few homes still burn heating oil. We don’t work on oil burners, but a switch to a heat pump or a gas or propane furnace is ours to price.
What a new furnace and AC costs in Great Falls.
$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
- Furnace alone, keeping your AC$4,285 to $14,040
- Heat pump system instead$8,499 to $21,650
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.
When replacing both makes sense in Great Falls.
Both halves went in the same year
An R-22 outdoor unit with a furnace of the same year beside it is the classic pair to replace as one. Put a new outdoor unit and coil on that furnace alone, and in a few winters the furnace under the new coil is the next call.
The outdoor unit runs on R-22
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.
A big repair on an old system
A compressor or heat exchanger on a system past 15 years deserves a replacement price beside it, and you’ll get both numbers.
Who signs off on a new system in Great Falls.
Fairfax County
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.
How to pick who replaces your furnace and AC in Great Falls.
Ask every company that quotes the job, us included.
Did they ask which floors each system serves?
In a house with two or three systems, the right size for each depends on the rooms it heats and cools, finished basement included. A quote that copies the old labels misses whatever the house has gained since it was built.
Do they size it to the house, or copy the old label?
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.
Is the whole job in the written price?
Furnace, outdoor unit, matching coil, refrigerant lines, thermostat, permit and hauling the old one away. If it isn’t on the paper, ask.
Already holding another company’s quote?
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.
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 and AC replacement questions from Great Falls.
Should I replace every system in my Great Falls house at once?
Only the ones that are due. A pair under ten years old that heats and cools well can stay. If you can’t tell which one is struggling, the diagnostic visit is $99, and the range applies to each system separately: $8,898 to $23,000 apiece, by size and efficiency.
Does the new outdoor unit go back on the old pad?
Usually, since the lines and wiring already run there. But Great Falls has many large and old trees, in the county plan’s own words, and a pad under them packs the coil with leaves and seed fluff. Replacement day is the time to move it somewhere open.
How much does a new furnace and AC cost in Great Falls?
$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.
Do I have to replace both at the same time?
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.
More from SwiftPro in Great Falls.
More from SwiftPro in Great Falls
Start with your number, then a written quote.
Call, book online, 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 is a licensed, BBB Accredited (A rating), independently owned heating, cooling and plumbing company in Chantilly, serving Great Falls 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.