Furnace replacement in Hamilton.
A propane furnace for a Hamilton house runs $4,285 to $14,040 installed, keeping your AC or heat pump. Just 22 owner homes here heat with piped gas.
- Installed price in writing
- Sized to the house, not the old nameplate
- Dedicated HVAC team
Get your furnace priced in writing
Hamilton furnaces draw on a propane tank and carry a long, hard January.
Piped natural gas is close to absent from 20158. The Census counts 22 owner homes heating with it, against 373 on propane and 665 on electricity, so a furnace we replace here almost always burns propane from a tank on the lot. Often it stands behind a heat pump that handles the milder weather, and this job keeps that outdoor unit and swaps only the furnace.
Winter here runs deep. The nearest NOAA station with long temperature records, the co-op in Purcellville 2.6 miles west-northwest, sits at about Hamilton’s 500 feet. Its 1991 to 2020 normals put close to 1,000 heating degree days in January alone, and more than half the year’s 4,942 fall from December through February, the months a heat pump hands more of the house to the flame behind it.
Some winters press harder. From January 25 through February 2, 2026, that station logged nine days in a row that never got above freezing, highs between 16 and 27 degrees; its daily records since 1960 show only two longer runs. On January 23, 2025, a weather station in Hamilton read 5 below zero, a reading the Weather Service lists as unofficial.
The Census dates 249 homes in the ZIP to before 1960, and the Town’s plan calls most of what stands in town late Victorian; there the furnace tends to sit in a basement, sharing a brick flue with the water heater. Another 657 went up in the 2000s and 2010s, so a propane furnace original to an early one has lit some twenty winters. A high-efficiency replacement usually exhausts through a side wall in plastic pipe, so the quote should show where.
Hamilton houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
Hamilton
ZIP 20158 as a whole: every Hamilton address, the Town and the countryside around it. The Census place for the Town alone has too few homes for steady figures.
- Median home built1988 Census
- Built before 1980about 4 in 10 Census
- Built since 2000about 4 in 10 Census
- Most homes aresingle-family houses, about 9 in 10 Census
- Heated withelectricity, about 5 in 10 Census
- Rentedabout 2 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 Hamilton.
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 Hamilton.
It quit on the coldest morning of the year
A furnace that stops at 5 below has usually been failing a while: a slow igniter, a fouled flame sensor, a louder inducer. The $99 diagnostic visit names the part; past twenty winters, ask for the repair and a replacement priced together.
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 Hamilton.
Questions to ask anybody who quotes you, us included.
Will the new furnace keep the old one’s input and its spot?
Since October 1, 2025, Loudoun County takes a propane or gas furnace replacement without plans when the BTUs and location stay as they were. A bigger furnace, or one moved, can still be right; the quote should say which it is.
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 showed up on time and was very thorough and quick. He diagnosed our problem and Tyler came in and gave us a great quote on a new unit. They came back and installed it the next day! They came through for us and I am very happy with their service. Will definitely use them again!
5.0 stars across 884 Google reviews. Read them on our reviews page.
Furnace replacement questions from Hamilton.
Who issues the permit for a propane furnace in Hamilton?
Loudoun County, inside the town limits or out on Harmony Church Road. Its Department of Building and Development issues building permits for the whole county, the towns included; zoning inside the limits is the Town’s. Virginia’s building code lets a like-for-like swap skip the permit only when the equipment isn’t gas-fired, and propane is a fuel gas.
Could a heat pump carry a Hamilton house without the propane furnace?
Plenty already do: 665 of the ZIP’s 1,298 owner homes heat with electricity. Keeping the propane furnace as backup puts a flame behind the house in a week like late January 2026. The HVAC replacement cost estimator prices a furnace or a full heat pump system for your house.
How much does a new furnace cost in Hamilton?
$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 Hamilton.
More from SwiftPro in Hamilton
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 Hamilton 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.