Open 24/7 for emergencies
AC repair in Dunn Loring starts with a $99 diagnostic visit, and a run capacitor is $240 to $370, priced from our book before any work.
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5.0 stars across 1,132 reviews
One of our HVAC technicians beside an outdoor unit at a Northern Virginia home, the vans at the curb.
Licensed and insuredVirginia Class A contractor #2705192276
24/7 emergency serviceOften same-day, and we will tell you honestly when we can get there.
Our own HVAC installersA dedicated heating and cooling team, separate from our plumbers
Price in writing firstYou see every option priced before anything is ordered
What it costs
The same price book as our AC repair page. The diagnostic visit is $99, and the common parts ride on the truck, so most of these get fixed on the first visit.
Run capacitor replaced
$240 to $370
Contactor replaced
$290 to $425
Condensate drain cleared
$175 to $420
Refrigerant topped up
$190 to $740
Blower wheel pulled and cleaned
$300 to $440
Refrigerant leak found and repaired
$1,850 to $2,700
or $31/mo at 0% APR for 60 months
Repair diagnostic visit
$99
Monthly figures: 60mo @ 0% APR on each starting price, the whole price financed, on approved credit. Longer plans lower the payment and cost more in total. The lender sets the final terms. How financing works
Often same-day, and we will tell you honestly when we can get there.
With Comfort+ membership, $20 a month or $199 a year, the diagnostic visit is included, any service is 15% off, and the cooling and heating maintenance visits are part of the membership.
What’s different in Dunn Loring
Dunn Loring’s own ZIP, 22027, is the newer end of the place: the typical owner’s house went up in 1991, about half in the 1980s and 90s and one in five since 2000, nine in ten of them detached. Those houses usually had central air from the start, so the trouble here is less often ductwork than equipment that has put in its years.
The nearest long-running weather record is a cooperative station in Vienna, 3.6 miles west. Its July afternoons average 84 degrees, with about 13 days a year at 90 or hotter, well under Dulles at 33. The nights are the hard part: July lows there average about 67, so a system here keeps running after dark, pulling water out of the air along with the heat. If the house feels sticky at 74, have the airflow and the temperature drop at the coil measured before anybody adds refrigerant.
Close to three owner homes in ten heat with electricity, which here usually means a heat pump, an outdoor unit with no off season. When we fix one in summer, the thermostat goes to heat for a few minutes before we pack up, so the reversing valve and the defrost controls get proven too. A failed defrost board is $450 to $1,150.
NOAA’s storm records filed under Dunn Loring include the June 29, 2012 derecho, when gusts estimated near 70 mph dropped three large branches across two lanes of Prosperity Avenue, a tree that fell onto a Metro car in July 2017, and a May 2018 storm that blew out an apartment building’s windows near the Metro station. After one like those, look at the outdoor unit before the cooling goes back on: limbs or leaves against the coil, fins folded flat, torn foam on the copper lines, a loose disconnect box. If anything looks wrong, keep it off and call us to check it all before it runs.
By the numbers
From the Census Bureau’s 2020 to 2024 survey. Median year built and heat count owner-occupied homes only.
ZIP 22027 as a whole: every Dunn Loring address. The Dunn Loring Census place is bigger: about three in four of its homes have Vienna mail.
What you’d notice
Power that drops and comes back a few times is hard on the two cheapest outdoor parts: the run capacitor, $240 to $370, and the contactor, $290 to $425. Set the thermostat to off for five minutes, then back to cool. If the outdoor fan still won’t start, call.
Usually the outdoor unit has stopped running. A hum with no fan turning is almost always the run capacitor; silence while the thermostat calls is usually the contactor.
That’s an airflow problem far more often than a refrigerant problem: a clogged filter, a matted coil, or a blower wheel packed with dust.
Choosing who fixes it
Questions worth asking anybody who comes out, us included.
They should. A summer repair that only proves cooling leaves the reversing valve untested until the first frost, which Vienna’s records put around October 29 in a typical year. Ask to see both modes run.
A company that prints what a capacitor or a contactor costs has already told you the number. One that won’t say until the tech is in your driveway hasn’t.
A healthy system drops the air somewhere around 16 to 22 degrees across the indoor coil. Low refrigerant means a leak, and topping it up every summer is the expensive way to find that out.
Some repairs aren’t worth doing on a 20-year-old system. The good answer shows you the repair price and the replacement price side by side and lets you pick.
Two of our crew going over a work order before the day's calls.
From our Google reviews
5.0 stars across 1,132 reviews. Read them on our reviews page.
Alex was very professional and the 2 technicians Oscar, and Derek was fast and efficient. They replace my A/C unit within the next day
Where we work
Next door to Dunn Loring: Vienna, Falls Church, McLean, Annandale and Oakton.
Questions
A repair takes no permit. A replacement is mechanical permit work with Fairfax County, the only building office Dunn Loring has, plus the County’s A2L certification for a system on the newer refrigerants.
Leave the thermostat off a few minutes first so the system’s pressures settle. Outages here can run long: Tropical Storm Irene left about 81,000 across Fairfax County in August 2011, Merrifield, just across I-66, among the hardest hit.
The diagnostic visit is $99. The common repairs: a run capacitor $240 to $370, a contactor $290 to $425, a condensate drain cleared $175 to $420, refrigerant topped up $190 to $740. A refrigerant leak repair runs $1,850 to $2,700.
Fix the cheap parts on almost anything. Think twice about a big repair on a system over 15 years old, and about any leak on an R-22 system. The HVAC estimator prices a new system in about a minute, so you can put the two numbers side by side.
Ready when you are
Call, or send the form at the top. The tech prices the repair from the book before starting, and if it’s the end of the road you’ll hear that first.
SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
Virginia Class A contractor license #2705192276
SwiftPro Heating, Cooling & Plumbing is a licensed, BBB Accredited (A rating), independently owned heating, cooling and plumbing company in Chantilly, serving Dunn Loring and the rest of Northern Virginia. Virginia contractor license #2705192276. 5.0 stars across 1,132 reviews on Google, Angi, Yelp, the BBB and Facebook. SwiftPro maintains a dedicated HVAC team and a dedicated plumbing team.
From SwiftPro Heating, Cooling & Plumbing in Chantilly. Housing figures are the Census Bureau’s American Community Survey, 2020 to 2024, for each place named; permit, water and sewer facts link to each office’s own page and were checked in September and October 2026.