Furnace replacement in Round Hill.
A propane furnace for a Round Hill house runs $4,285 to $14,040 installed, keeping your heat pump or AC. In 20141, propane outnumbers piped gas about 20 to 1.
- Installed price in writing
- Sized to the house, not the old nameplate
- Dedicated HVAC team
Get your furnace priced in writing
A Round Hill furnace burns propane, and its new vent has to clear a three-foot snow.
The Census counts 46 owner homes in the 20141 ZIP heating with utility gas, against 953 on propane and 1,257 on electricity. So a Round Hill furnace coming due is nearly always a propane furnace drawing on a tank in the yard, and the heat pump or air conditioner out back usually stays.
Those furnaces work a longer season than eastern Loudoun’s. NOAA’s 1991 to 2020 normals for the Purcellville weather station, about three miles east-northeast of town, add up to 4,942 heating degree days in an average year, roughly 7 percent more than Dulles Airport, with January nights averaging 24.5 degrees. A mile southeast of Round Hill, a station logged 5 below on the morning of January 23, 2025, a reading the Weather Service lists as unofficial. That’s the kind of morning a heat pump hands the house to the propane furnace behind it.
Most came with the subdivisions. The Town’s plan describes its water and sewer system growing very fast from the mid 1990s through 2005, and the Census dates 604 homes in the ZIP to the 1990s and 871 to the 2000s, so a builder furnace here has lit twenty to thirty winters. Many from that era were standard-efficiency units venting up a metal flue; a high-efficiency replacement vents through a side wall in plastic pipe instead.
That wall matters out here. A Weather Service spotter measured 36.3 inches of snow a mile west-northwest of town in the January 2016 blizzard. Furnace instructions generally put the intake and exhaust above the snow line that wall can expect, because pipes buried by a drift trip the burner off on its pressure switch. We pick the exit away from where drifts pile, the deck stairs and the propane regulator.
Round Hill houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
Round Hill
ZIP 20141 as a whole: every Round Hill address, the Town and the neighborhoods around it. The Census place for the Town alone has too few homes for steady figures.
- Median home built2004 Census
- Built before 1980about 2 in 10 Census
- Built since 2000about 6 in 10 Census
- Most homes aresingle-family houses, about 9 in 10 Census
- Heated withelectricity, about 5 in 10 Census
- Rentedabout 1 in 10 Census
- Propane heats a real share of homes here, and we replace propane furnaces too.
- Most homes here heat with electricity, usually a heat pump; a furnace swap here is for the gas and propane houses.
What a new furnace costs in Round Hill.
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 Round Hill.
Storm water reached the furnace
On May 5, 2025, the Blue Ridge Volunteer Fire Department reported several flooded basements and water over roads a few miles north-northeast of town. A gas valve or control board that sat in floodwater gets replaced, not dried out and relit, and on an older furnace that often settles it. After a storm puts water near yours, leave it off and call us to check it first.
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.
You heat with propane
We replace propane furnaces as well as natural gas ones. The new furnace is set up for propane before it’s lit, and the quote is written for your house.
How to pick the best furnace replacement company in Round Hill.
Questions to ask anybody who quotes you, us included.
Did they ask when the heat pump hands off to the furnace?
Where a propane furnace backs up a heat pump, the thermostat’s switchover temperature decides how much of the winter each one carries. Ask that the quote include setting it for the new furnace, and what temperature they’d pick for a Round Hill winter.
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 Round Hill.
Does swapping a propane furnace need a permit in Round Hill?
Yes. Propane is a fuel gas, so the swap takes a Loudoun County fuel gas permit, inside the town limits and out; Virginia’s building code skips the permit on a like-for-like swap only when the equipment isn’t gas-fired. Since October 1, 2025, the County waives plan review when the input rating and the location stay as they were. The Town’s own zoning permit is for work like additions, decks and finished basements.
How much does a new furnace cost in Round Hill?
$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 Round Hill.
More from SwiftPro in Round Hill
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 Round Hill 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.