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Chantilly Homes Compared With Fairfax County
Chantilly sits in Fairfax County, Virginia. The table shows how its housing differs from the county as a whole, which decides what a duct and dryer vent visit checks first.
| Measure | Chantilly | Fairfax County |
|---|---|---|
| Median year built | 1987 | 1983 |
| Built in the 1980s | 44% | 23% |
| Detached houses | 61% | 46% |
| Townhomes | 23% | 23% |
| Heat with natural gas | 49% | 54% |
| Heat with electricity | 48% | 42% |
| Owner-occupied | 81% | 69% |
Source: U.S. Census Bureau, American Community Survey 2024 5-year estimates. Figures are estimates and are rounded.
Chantilly or South Riding? Same Mailing Name, Two Counties
The Chantilly mailing name covers two different places. The Chantilly census-designated place is in Fairfax County. South Riding, west of the county line, is in Loudoun County. Both use Chantilly addresses and share ZIP codes 20151 and 20152.
| Measure | Chantilly CDP | South Riding CDP |
|---|---|---|
| County | Fairfax | Loudoun |
| Median year built | 1987 | 2006 |
| Main housing type | Detached houses (61%) | Detached (49%) and townhomes (46%) |
| Main heating fuel | Gas and electric, about half each | Natural gas (81%) |
Homes in South Riding are newer and mostly gas-heated, so they need a different first check; the South Riding page covers them.
Original Ductwork in 1980s Subdivisions
A Chantilly house built in the 1980s is about 40 years into its first set of ducts. The cloth tape used on joints in that era dries out and lets go, and ENERGY STAR estimates that a typical house loses 20 to 30 percent of its duct air to leaks. Leaks on the return side pull dusty attic, garage or basement air into the system.
When the furnace or heat pump is replaced, the ducts usually stay. That is the moment to inspect and seal them; the duct inspection page explains what a camera check shows.
Gas Furnace or Heat Pump
Chantilly splits almost evenly between natural gas (49 percent) and electricity (48 percent). A gas furnace needs yearly service before winter, and the Consumer Product Safety Commission advises carbon monoxide alarms on every level of the home. A heat pump runs the blower for long stretches in both seasons, so its filter loads faster.
Dryer Vents in Detached Houses
In a detached house the dryer usually vents through a basement or first-floor wall, a short run that sits at the low end of the $135 to $360 cleaning range. Second-floor laundry rooms added during a remodel often vent through a long run or the roof, which costs more to clean.
Chantilly Duct and Dryer Vent FAQs
Is Chantilly in Fairfax County or Loudoun County?
The Chantilly census-designated place is in Fairfax County. South Riding, which shares the Chantilly mailing name and ZIP codes 20151 and 20152, is in Loudoun County.
How much does air duct cleaning cost in Chantilly, VA?
Whole-system air duct cleaning in Chantilly runs about $500 to $800 per system. Townhomes usually run $190 to $650, and dryer vent cleaning runs $135 to $360.
Should I clean or seal the ducts in a 1980s Chantilly house?
Inspect first. In a house with its original 1980s ducts, leaking joints are a common finding, and sealing them fixes the source of the dust. Cleaning helps when the inspection shows heavy dust, debris or pest contamination.
Do gas furnaces in Chantilly need carbon monoxide alarms?
Yes. A gas furnace produces carbon monoxide. The Consumer Product Safety Commission advises carbon monoxide alarms on every level of the home, and the furnace needs service before each heating season.