Ductless mini splits in Fairfax.
A one-zone ductless mini split runs $7,000 to $10,000 installed in Fairfax, often for a sunroom, an addition or a finished basement the ducts never reached.
- Published price ranges
- Heats and cools, room by room
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Fairfax rooms the ducts never reached, from 1960s additions to top floors.
Plenty of 1960s houses in the City of Fairfax and Mantua have grown since they were built: a family room off the back, a sunroom, a finished basement, a garage turned into a bedroom. The ductwork rarely grew with them. Stretching a duct run out to the new room starves the rooms already on it, which is why a mini split, one head in that room on its own outdoor unit, is the usual fix.
Long Branch and Greenbriar are the same story on bigger lots, mostly single-family houses from around 1970, the kind of house where an addition out back is the room the system never reaches.
Fair Lakes is the opposite problem. About a third of its homes are townhouses, most from the late 1990s and 2000s, where the top floor runs warm all summer and the lowest level runs cool, all on one thermostat. A head in the top-floor bedroom gives that floor its own setting without touching the system that runs the rest.
Inside the City of Fairfax the permit comes from the City’s own office. Everywhere else on a Fairfax address, it’s Fairfax County, and the rules for the county side are below.
Where a mini split usually goes across Fairfax.
Census figures for the owner-occupied homes in each place, and the room a ductless head usually ends up in.
| Place | Median home built | Most homes are | Heated with | Where ductless usually fits |
|---|---|---|---|---|
| Fair Oaks | 1995 | condo and apartment buildings, about 5 in 10 | gas, about 6 in 10 | Condo buildings: an outdoor unit needs the association’s yes. |
| City of Fairfax | 1966 | single-family houses, about 5 in 10 | gas, about 7 in 10 | Additions, sunrooms and upstairs rooms the old ducts barely reach. |
| Fairfax Station | 1982 | single-family houses, about 9 in 10 | gas, about 5 in 10 | 1980s and 90s houses: the bonus room, the sunroom, the far bedroom. |
| Kings Park West | 1976 | single-family houses, about 7 in 10 | gas, about 5 in 10 | Additions, sunrooms and upstairs rooms the old ducts barely reach. |
| Merrifield | 1990 | condo and apartment buildings, about 6 in 10 | gas, about 6 in 10 | Condo buildings: an outdoor unit needs the association’s yes. |
| Fair Lakes | 1998 | townhouses, about 3 in 10 | gas, about 7 in 10 | 1980s and 90s houses: the bonus room, the sunroom, the far bedroom. |
| Long Branch | 1968 | single-family houses, about 9 in 10 | gas, about 7 in 10 | Additions, sunrooms and upstairs rooms the old ducts barely reach. |
| Mantua | 1968 | single-family houses, about 7 in 10 | gas, about 7 in 10 | Additions, sunrooms and upstairs rooms the old ducts barely reach. |
Fairfax houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
The City of Fairfax
- Median home built1966 Census
- Built before 1980about 7 in 10 Census
- Built since 2000about 2 in 10 Census
- Most homes aresingle-family houses, about 5 in 10 Census
- Heated withgas, about 7 in 10 Census
- Rentedabout 3 in 10 Census
- Ducts in houses this age were often sized for the furnace, not for cooling, so upstairs rooms run warm in July.
- In a gas-heated house a mini split adds heat pump heating to one room; the furnace keeps the rest.
The Fairfax County side
Most of the Fairfax Station Census place, in the table, has Fairfax mail, so it counts here.
What a ductless mini split costs in Fairfax.
Installed, from the price book our HVAC price estimator runs on. A zone is one room with its own indoor head, and you get the price in writing before you decide.
- Ductless mini split, one zone, installed$7,000 to $10,000
- Ductless mini split, two zones, installed$11,000 to $15,000
- Ductless mini split, three zones, installed$12,500 to $18,000
- Ductless mini split, four zones, installed$16,000 to $21,000
- Ductless mini split, five zones, installed$19,000 to $25,000
- Ductless mini split, six zones, installed$23,000 to $30,000
Where you land in a range is mostly the distance from the outdoor unit to the room, the kind of head and the room left in the electrical panel.
The second zone costs the most because it often needs a bigger outdoor unit. Our mini split cost guide explains.
When a ductless mini split makes sense in Fairfax.
The sunroom is unusable from June to September
Glass on three sides gains heat faster than any duct can carry it out, and the room was probably never on the duct plan to begin with. A head sized for the glass, not just the floor area, is what makes it a room again.
The far rooms never got the cooling
Plenty of older houses got central air added years after they were built, and the rooms at the end of the duct run are the ones that stay warm.
One room is always wrong
The bonus room, the sunroom, the bedroom over the garage. We check for a closed damper or a crushed duct first; sometimes that’s all it is.
Who signs off on a mini split in Fairfax.
How to pick the best mini split installer in Fairfax.
Questions worth asking anybody who quotes you, us included.
Did they ask how you use the room?
A home office that runs all day, a guest room used twice a year and a sunroom full of glass need different sizes. Ask the installer to size the head for the room’s windows, exposure and use, not only its square footage.
Did they check the rest of the house first?
If the room’s trouble is a closed damper or a crushed duct, a mini split is an expensive fix for a cheap problem. Ask what they checked first.
Is the whole job in the price?
Ask whether it covers the line set run, the new circuit and putting the walls back, or only the equipment.
What our customers say.
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Ductless mini split questions from Fairfax.
Does a mini split need a permit in Fairfax?
On the county side, yes: Fairfax County treats heating and cooling equipment as mechanical permit work, and a system on the newer A2L refrigerants needs a refrigeration certification with the permit. Inside the City of Fairfax, the City’s own permit office handles it.
Can one outdoor unit run heads in two Fairfax rooms?
Yes. A multi-zone outdoor unit runs two or more heads, and two zones run $11,000 to $15,000 installed. If a second room might come later, price it now: a single-zone outdoor unit can’t take a second head.
How much does a ductless mini split cost in Fairfax?
Installed, one zone is $7,000 to $10,000, two zones $11,000 to $15,000 and three zones $12,500 to $18,000, up to $23,000 to $30,000 for six. The HVAC price estimator gives your number.
Does a mini split heat, or only cool?
Both. A ductless system is a heat pump, and cold-climate models keep heating well below freezing, which covers a Northern Virginia winter.
More from SwiftPro in Fairfax.
More from SwiftPro in Fairfax
Tell us which room it is.
Call, or book online and pick a window. You get the installed price in writing before anything goes on the wall.
SwiftPro Heating, Cooling & Plumbing is a licensed, BBB Accredited (A rating), independently owned heating, cooling and plumbing company in Chantilly, serving Fairfax 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.
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