Furnace and AC replacement in Sterling.
Furnace and AC replacement in Sterling runs $8,898 to $23,000 installed. Over half of Sterling’s homes date from 1980 to 1999, and their systems age as a set.
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- Sized to the house, not the old label
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Get your new system priced
A town built mostly in the 1980s and 90s ends up replacing whole systems.
More of our Sterling calls end in a full system replacement than in any other town where we work regularly. The Census helps explain it. Over half the homes across Sterling’s Census places went up from 1980 through 1999, and the typical owner home around Sterling Park dates from 1979, against 2003 for Loudoun County as a whole. Sterling is a generation older than the county around it, and most of it was built inside one twenty-year stretch.
That timing shapes the job. A Sugarland Run house, typical owner home from 1983, or a Cascades or Lowes Island one from 1996, has usually been through its builder’s furnace and air conditioner already. Where the second pair went in together, often in the 2000s, both halves have now run close to twenty years side by side, and one big repair on either is the cue to price both.
The pair isn’t always a furnace and an air conditioner. Countryside heats mostly with electricity, nearly eight owner homes in ten, and around Sterling Park just over half, which here usually means a heat pump outside and an air handler with backup strips inside; that whole system runs $8,499 to $21,650 installed. Cascades and Lowes Island have the classic pair, a gas furnace with an air conditioner out back.
Size gets a fresh look. Lowes Island is mostly detached houses, and the bigger ones often run a second system for the bedrooms, each priced on its own. A Sugarland Run house may have gained a finished basement since its first system was sized. Loudoun County handles the paperwork, since Sterling has no town hall: a mechanical permit for the equipment, and a separate gas permit for a gas furnace.
The systems across Sterling, place by place.
Census figures for the owner-occupied homes in each place, and what that usually means for a replacement.
| Place | Median home built | Most homes are | Heated with | What the system usually is |
|---|---|---|---|---|
| Sterling | 1979 | single-family houses, about 5 in 10 | electricity, about 5 in 10 | Mostly electric heat, so usually a heat pump swap instead. |
| Lowes Island | 1996 | single-family houses, about 6 in 10 | gas, about 7 in 10 | Townhouse systems: a furnace in a closet or attic, the air conditioner out back. |
| Cascades | 1996 | townhouses, about 4 in 10 | gas, about 8 in 10 | 1980s and 90s houses, most on their second furnace and AC. |
| Sugarland Run | 1983 | single-family houses, about 6 in 10 | gas, about 5 in 10 | 1980s and 90s houses, most on their second furnace and AC. |
| Dulles Town Center | 1998 | condo and apartment buildings, about 5 in 10 | gas, about 9 in 10 | Condo closet systems: small units, often with association rules for the outdoor half. |
| Arcola | 2017 | townhouses, about 5 in 10 | gas, about 8 in 10 | Townhouse systems: a furnace in a closet or attic, the air conditioner out back. |
| Oak Grove | 2005 | townhouses, about 8 in 10 | gas, about 9 in 10 | Townhouse systems: a furnace in a closet or attic, the air conditioner out back. |
Sterling houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
Sterling
- Built before 1980about 2 in 10 Census
- Built since 2000about 2 in 10 Census
- Most homes aresingle-family houses, about 4 in 10 Census
- Heated withgas, about 6 in 10 Census
- Rentedabout 3 in 10 Census
- Electric heat here usually means a heat pump with backup strips, which is priced as a heat pump system, not a furnace and AC.
- Townhouse furnaces sit in closets and attics, so the path in matters as much as the size.
What a new furnace and AC costs in Sterling.
$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 Sterling.
Both data plates show the same 2000s year
The label on the outdoor unit and the one inside the furnace door each carry a date. If both land in the same few years of the 2000s, the pair has worked close to twenty Sterling winters and summers together, and when one needs a compressor or a heat exchanger, the other usually isn’t far behind.
Your heat may not be a furnace
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 AC died and the furnace is the same age
A new outdoor unit needs a matching coil, and on a gas system the coil sits on the furnace. If the furnace is as old, do both and open that closet once.
Who signs off on a new system in Sterling.
Loudoun County
Loudoun County requires a permit to swap a gas water heater or furnace. Since October 2025, a replacement that keeps the same BTUs in the same spot needs no plans. Source.
How to pick who replaces your furnace and AC in Sterling.
Ask every company that quotes the job, us included.
Did they price gas, electric and dual fuel side by side?
In Sugarland Run and around Sterling Park, neighbors on one street often heat different ways. With a gas line in, ask for three lines on one page: a furnace and air conditioner, a heat pump system, and a heat pump paired with a gas furnace. Our dual fuel guide explains the third.
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.
Oscar and Ndung were great technicians for our HVAC install! Very knowledgeable and friendly. Would recommend them to others!
5.0 stars across 884 Google reviews. Read them on our reviews page.
Furnace and AC replacement questions from Sterling.
Should a Sterling air conditioner be oversized for the summer?
No. NOAA’s normals for Dulles Airport, next to Sterling, count about 33 days a year at 90 degrees or hotter, fewer than Reagan National’s 40. An oversized air conditioner cools the house fast and shuts off before it has pulled the moisture out, so the rooms feel clammy. The new one gets sized to the house, not to the hottest afternoon of the year.
How much does a new furnace and AC cost in Sterling?
$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 Sterling.
More from SwiftPro in Sterling
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 Sterling 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.