Manual J load calculation
Room-by-room heat gain calculation using ACCA-approved software. This determines the correct tonnage and airflow for your house. We do not guess based on square footage or copy the old system's size.
Licensed
Licensed & Bonded
Fully Insured
Insured & Bonded
24/7 Emergency
Same-Day Response
Warranty Backed
22+ Years Trusted in Fairfax
What is included in a standard install
Every AC installation we do includes the core work needed to get your system running to code. Some items, like new ductwork or electrical panel upgrades, are quoted separately because not every home needs them. Here is what is standard.
Equipment and materials
New condenser, evaporator coil, line-set, pad, disconnect, thermostat, and PVC condensate line. We use R-410A or R-32 refrigerant depending on the system. Copper tubing is cut, flared, and brazed on site.
Permit and inspection
We pull the Fairfax County mechanical permit and meet the inspector on site. The final sign-off is included. You get a copy of the inspection record for your files.
Startup and commissioning
Nitrogen pressure test, evacuation to 500 microns, refrigerant charge by weight, and a full cooling cycle. We measure static pressure, temperature split, and verify the condensate drain flows freely before we leave.
Warranty registration
We register your equipment warranty the same day, which locks in 10-year parts coverage on most brands. Our 5-year workmanship warranty is documented in writing and emailed to you.
What AC installation Fairfax VA really involves
AC installation Fairfax VA is the full mechanical process of replacing or adding a cooling system: load calculation, equipment selection, line-set fabrication, electrical hookup, refrigerant charging, and commissioning. It is not a box swap. We start with a Manual J load calculation, then match capacity to your ductwork and insulation. Copper tubing gets cut, flared, and brazed with a torch kit; the system is evacuated with a vacuum pump and charged by weight using a manifold gauge set. Every install is permitted and inspected under Virginia code.
Fairfax summers push 95°F with heavy humidity, and most of the housing stock here was built between 1950 and 1990 with undersized returns. That combination kills compressors early. If your system is 12 to 15 years old, R-22 refrigerant is gone, or you have added a finished basement, new AC installation in Fairfax VA with financing makes more sense than another repair. We see it every week in Fairfax County: a 3-ton unit straining to cool a house that really needs 3.5 tons.
How our AC installation process works
From the first call to the final walkthrough, here is exactly what happens when you book an install with us. Most jobs are done in one day; two-story replacements with ductwork run two.
01
Schedule
Call or book online — a real human picks up and confirms a 2-hour arrival window.
02
Diagnose
Licensed tech inspects on-site, then walks you through the cause and your options.
03
Fix
The job is completed to code and done right the first time — no shortcuts, no surprises.
04
Guarantee
Every job backed by a written workmanship warranty — and we stand behind it.
Tools and methods we use on every install
Tools & Equipment
Manifold gauge set
Used to read high-side and low-side pressures during evacuation and charging. We charge refrigerant by weight, then verify with gauges and a temperature split across the coil.
Vacuum pump and micron gauge
Pulls the system down to 500 microns before charging. Skipping this step leaves moisture in the line-set, which forms acid and kills compressors within a few years.
Refrigerant recovery machine
Recovers old R-22 or R-410A from the system before removal. Required by EPA Section 608 rules. We recover, weigh, and document every charge.
Clamp meter and multimeter
Tests amp draw on the compressor and blower motor, verifies capacitor microfarads, and checks contactor voltage. This catches electrical problems before they trip a breaker.
Tube cutter, flaring tool, and torch kit
Cuts and preps copper tubing, forms flare fittings, and brazes joints with nitrogen flowing to prevent oxidation inside the line-set.
Psychrometer
Measures wet-bulb and dry-bulb temperatures to calculate indoor humidity and verify the system is removing moisture, not just dropping temperature.
Methods & Standards
Manual J load calculation
Room-by-room heat gain calculation following ACCA quality standards. We measure windows, insulation, ceiling height, and orientation. This is the only reliable way to size a system correctly, and it is the first step on every quote.
Nitrogen pressure test
We pressurize the line-set with dry nitrogen to 300 psi and hold it for 30 minutes. Any pressure drop means a leak. This catches bad braze joints and flare fittings before the system is charged.
Weigh-in charging
Refrigerant is charged by weight using a digital scale, not by guessing from gauge readings alone. This matches the manufacturer's specified charge and protects the compressor warranty.
Static pressure testing
We measure static pressure across the air handler and filter to confirm the ductwork can handle the rated airflow. High static pressure means the system runs hot and inefficient, even if it is sized correctly.
When Fairfax homeowners call us
01
A 1990s colonial in Burke with the original 3-ton system still running on R-22 and a slow leak.
What we do: We quote a 3-ton 16-SEER2 Carrier replacement with a new line-set, pad, and disconnect. The old refrigerant is recovered, the system is permitted, and the install is done in one day.
→ Cooling restored, electric bill drops about $95 a month in summer, and the homeowner gets a 10-year parts warranty plus our 5-year workmanship warranty.
02
A Vienna homeowner finishing a basement and adding 600 square feet of conditioned space.
What we do: We run a new Manual J calculation, find the existing 2.5-ton unit is now undersized, and install a 3.5-ton variable-speed system with a zone damper for the basement.
→ Both floors hold 72 degrees in July. The variable-speed blower keeps humidity near 50 percent, and the homeowner avoids a second system.
03
A Fairfax Station homeowner with a 1970s ranch and no existing ductwork.
What we do: We install a Mitsubishi Electric ductless mini-split system with three wall heads and one outdoor condenser, running line-sets through the attic and down exterior walls.
→ Room-by-room control, no ductwork needed, and a system that cools the whole house for roughly the same cost as a central install.
04
An Annandale landlord with a rental property whose AC failed inspection before a new tenant moved in.
What we do: We prioritize the job, pull the permit the same week, and install a Goodman 14.3-SEER2 system with a basic thermostat to keep costs down for the owner.
→ Inspection passed, tenant moved in on schedule, and the owner has a documented warranty for the next tenant turnover.
How AC installation works in Fairfax
Fairfax sits in a humid subtropical climate with summers that routinely hit 95°F and dew points above 70°F. That combination puts more stress on a cooling system than the dry heat out west. Most of the housing stock in Fairfax County was built between 1950 and 1990, and a lot of it has undersized return ducts and original 8-inch flex runs. When we quote an energy efficient AC installation Fairfax VA, we check duct capacity first, because a high-SEER system on bad ductwork will not deliver its rated efficiency. We also deal with Fairfax County permit timelines, which run 3 to 7 business days for a mechanical permit. If you are in ZIP 22030, 22031, or 22037, we know the inspectors and the typical turnaround. We schedule installs so the permit is approved before the truck rolls, which keeps your project on a single-day timeline whenever possible.
Neighborhoods We Serve
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Old Town Fairfax
Older homes near downtown often have updated electrical panels but original ductwork. We frequently need to modify returns to handle a modern 3-ton system.
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Fairfax Station
Larger lots and longer line-set runs. We size line-sets carefully and often add a hard-start kit for the longer refrigerant runs.
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Fair Lakes
Newer construction with tighter envelopes. Load calcs here often come in lower than the original equipment tonnage, which means homeowners can downsize and save.
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Little River Hills
Mix of 1960s ranches and 2000s rebuilds. We see a lot of mismatched equipment where the AC and furnace were replaced years apart.
Local Conditions We Plan For
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High summer humidity and dew points above 70°F
Systems must be sized for latent load, not just temperature. An oversized unit short-cycles and leaves the house clammy at 55 percent humidity or higher. We size for moisture removal, not just tonnage.
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Older housing stock with undersized return ducts
A 3-ton system needs roughly 1,200 CFM of return air. Many Fairfax homes have returns sized for 800 CFM. We measure static pressure and modify ductwork when needed to hit the rated airflow.
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Fairfax County mechanical permit timelines
Permits run 3 to 7 business days. We pull the permit the day you approve the quote so the inspection is scheduled before install day. That keeps the project on a single-day timeline in most cases.
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Mixed heating and cooling equipment ages
Many Fairfax homes have a newer furnace paired with an older AC, or vice versa. We check compatibility, including coil match and refrigerant type, before quoting a replacement.
Burke colonial: 3-ton R-22 to 16-SEER2
Cooling problems we solve for Fairfax homes
Most no-cool calls come down to a handful of failures. Here are the ones we see most often in Fairfax County, and how a proper install or repair fixes them.
Problem
AC not cooling on a 98-degree afternoon
The house climbs past 80 degrees by mid-afternoon, humidity rises, and the system runs nonstop without dropping the temperature. Compressor damage can follow within days.
Our Fix
We check refrigerant charge with a manifold gauge set, test the capacitor and contactor with a multimeter, and verify airflow. If the compressor is failing, we quote a replacement system with financing options instead of a short-lived repair.
Problem
Frozen evaporator coil blocking airflow
Ice builds on the indoor coil, airflow drops to a trickle, and the system stops cooling entirely. Left alone, the compressor overheats and fails.
Our Fix
A frozen coil usually means low refrigerant or restricted airflow. We recover the refrigerant, pressure-test the line-set for leaks, repair the leak, and recharge by weight. If the coil is damaged beyond repair, we replace it.
Problem
Clogged condensate drain flooding the floor
Water backs up into the drain pan and overflows, damaging drywall, ceilings, and flooring. In Fairfax's humid summers, algae grows in the PVC line within a season.
Our Fix
We clear the line with a vacuum and install a float switch to shut the system down if the drain clogs again. On new installs we route the condensate line with proper slope and add a cleanout for future service.
Problem
R-22 system that cannot be legally recharged
R-22 production ended years ago, and the remaining supply is expensive. A leaking R-22 system can cost $800 or more just for refrigerant, with no guarantee it holds.
Our Fix
We quote a full replacement with R-410A or R-32 equipment. New systems use refrigerant that is widely available and far cheaper to service. Most Fairfax homeowners recoup the difference in two to three summers of lower bills.
Why Fairfax homeowners replace instead of patch
A new system is not a luxury when your July electric bill hits $400 and the house still won't cool below 78°F. Here is what a properly sized install actually buys you.
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Lower summer bills
A 16-SEER2 system replacing a 10-SEER unit cuts cooling costs roughly 30 to 40 percent. In Fairfax, that is $80 to $140 a month from June through September. We verify airflow and charge so the rated efficiency actually shows up on your Dominion bill.
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Correct sizing, no guesswork
We run a room-by-room Manual J load calculation before quoting. Oversized equipment short-cycles, leaves humidity at 60 percent, and wears out in 8 years instead of 15. Undersized equipment runs nonstop. Getting the tonnage right is the single biggest factor in comfort.
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Quieter, cleaner air
Modern variable-speed blower motors and ECM motors hold fan speed steady, so you hear a hum instead of a roar. Paired with a MERV 11 filter and a sealed return, this drops dust and pollen through the house. Allergy sufferers notice within the first week.
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Warranty and parts coverage
New Carrier, Trane, and Lennox equipment carries 10-year parts warranties when registered. We add a 5-year workmanship warranty on the install itself, covering refrigerant lines, drain, electrical, and startup. That is real coverage, not a handshake.
Licensed, certified, and reviewed
Licensed & Certified
- NATE Certification — issued by North American Technician Excellence
- EPA Section 608 Certification — issued by U.S. Environmental Protection Agency
- Virginia HVAC License — issued by Virginia Department of Professional and Occupational Regulation
- ACCA Quality Standards — issued by Air Conditioning Contractors of America
- AHRI Certification — issued by Air-Conditioning, Heating, and Refrigeration Institute
Verified Reviews
Google ★★★★★4.9
Replaced our 15-year-old system in one day. They pulled the permit, ran a load calc, and showed me why the old unit was undersized. Clean work, no surprises on the bill. The new Carrier is quiet and the house finally cools evenly.
Yelp ★★★★★4.8
Called on a Tuesday, had a quote by Wednesday, install on Friday. They recovered the old R-22, replaced the line-set, and had the county inspector out the following week. Financing made the monthly payment easy to handle.
BBB ★★★★★4.9
Third time using Fairfax HVAC Experts. They installed a ductless system in our addition two years ago and just replaced the main AC. Same crew, same quality. They clean up better than any contractor we have hired.
Google ★★★★★5.0
Our AC died during the July heat wave. They came out the same day, diagnosed a failed compressor, and quoted a replacement with financing. New system was in two days later. House was back to 72 degrees before the weekend.
Two decades of Fairfax cooling work
We have been installing and servicing cooling systems in Fairfax County since 2004, which means 22 years of Northern Virginia summers, code changes, and equipment evolution. Our techs hold NATE certification and EPA Section 608 certification, and we hold a Virginia HVAC license. We have commissioned thousands of systems across Fairfax, Vienna, Annandale, and Burke, from 1.5-ton condo units to 5-ton dual-zone setups. We know which brands hold up in this climate and which ones fail early.
- 22 years serving Fairfax County, founded 2004
- NATE-certified technicians on every install crew
- EPA Section 608 certified for refrigerant handling
- Virginia HVAC licensed and fully insured
- ACCA quality standards followed on every load calculation
What Fairfax homeowners say
Real experiences from customers who chose our AC Installation services.
“Our 14-year-old Trane finally quit in July. Fairfax HVAC Experts came out the same day, ran a load calc, and showed me why the old 3-ton was undersized for our addition. New 3.5-ton Carrier went in two days later. House holds 72 degrees now, and the electric bill dropped about $110 the first full month.”
M
Marcus T.
Homeowner, Fairfax Station
“We got four quotes for a new system. These guys were the only ones who actually measured the rooms and checked the ductwork. The others just matched the old tonnage. Install was clean, they pulled the permit, and the county inspector passed it first try. Financing made the monthly payment manageable.”
P
Priya R.
Homeowner, Vienna
“Replaced a 1998 Lennox with a Mitsubishi ductless setup for our finished basement and a new central system upstairs. They ran new copper, replaced a rotted drain pan, and cleaned up every scrap. Took two days as promised. Six months in, no issues and the humidity in the basement is finally under control.”
D
Dan K.
Homeowner, Annandale
Frequently asked questions about AC installation in Fairfax
Real answers to the questions we hear most often from local homeowners and property managers.
How much does AC installation cost in Fairfax VA?
Most full-system replacements in Fairfax run $5,800 to $12,500 in 2026, installed. A basic 2-ton 14.3-SEER2 unit with existing ductwork sits near the low end; a 4-ton variable-speed system with new line-set and duct modifications lands near the top. Add $1,200 to $2,800 if you need a new pad, disconnect, or condensate pump.
What size AC unit do I need in Fairfax VA?
Size comes from a Manual J load calculation, not square footage alone. A 1,800-square-foot Fairfax rambler with average insulation usually needs 2.5 to 3 tons. A 3,200-square-foot two-story colonial with west-facing windows often needs 4 to 5 tons. We measure every room and check duct capacity before quoting tonnage.
How long does AC installation take in Fairfax VA?
A straight swap on an existing pad and line-set takes 6 to 8 hours, done in one day. If we are running new copper, modifying ductwork, or upgrading the electrical disconnect, plan on two days. We give you a two-hour arrival window and clean up before we leave.
Do you offer financing for AC installation in Fairfax VA?
Yes. We work with approved lenders offering 12- to 84-month terms, including 0 percent for 18 months on qualifying systems. Approval usually takes 10 to 15 minutes online or over the phone. Ask for the financing sheet when we do your estimate so you can compare monthly payments side by side.
Other HVAC services we handle in Fairfax
Emergency HVAC Repair
When your AC dies at 9 p.m. on a 98-degree Saturday, we run 24/7 emergency calls across Fairfax. Most no-cool calls trace to a tripped breaker, failed capacitor, or clogged condensate drain. We diagnose and repair on the first visit whenever parts allow.
View Emergency HVAC RepairAC Repair
Not every system needs replacing. If your unit is under 12 years old and the repair is under $1,500, fixing it usually beats financing a new one. We handle refrigerant leaks, blower motor failure, thermostat malfunction, and frozen evaporator coils.
View AC RepairAC Replacement
When repair costs pass half the price of a new system, replacement is the smarter move. We handle full condenser and coil swaps, line-set replacement, and pad upgrades. Most replacements are permitted and completed in a single day.
View AC ReplacementFurnace Repair
Your furnace shares the air handler and thermostat with your AC, so we see both systems on most calls. Common issues include igniters that fail to light, dirty flame sensors, and cracked heat exchangers. We repair gas and electric furnaces across Fairfax County.
View Furnace RepairFurnace Installation
If you are replacing the AC, it often makes sense to replace the furnace at the same time. You save on labor and get matched equipment. We install 80 percent and 96 percent AFUE furnaces and handle the gas piping and venting.
View Furnace InstallationHeat Pump Repair
Heat pumps cool in summer and heat in winter, so a failure hits twice as hard. We diagnose reversing valves, defrost boards, and auxiliary heat strips. If your heat pump is not defrosting or is stuck in one mode, call us before the season turns.
View Heat Pump RepairCall Fairfax HVAC Experts
Reach us at +1 (571) 760-4715 any time, day or night. Our office is open Monday through Friday from 8 a.m. to 6 p.m., and emergency dispatch runs 24/7. Most calls placed before noon get a same-day visit.
Fairfax HVAC Experts
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Phone
+15717604715 -
Address
14500 Chronical Dr, Fairfax, VA 22030
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Hours
Mon–Fri: 7AM – 7PM
Sat: 8AM – 4PM
Sun: Emergency Only
24/7 Emergency Available