AC Installation in Herndon, VA
A new air conditioner in Herndon will run from June through September every year. Tell us about the house, and a licensed contractor who covers Fairfax County will get in touch.
Tell us about the job
It takes about a minute.
Four months of real heat, every year
Summer afternoons in Herndon average 86°F, and a new air conditioner runs from June through September to keep up. That's four months of steady work, not just a few hot weeks.
The area has also logged 387 damaging wind events and 51 hail events over the past ten years, so the outdoor unit has to hold up to more than heat. Any central air conditioner installed new here has to meet the federal minimum of 14.3 SEER2.
- 4 months
- June through September, your air conditioner is on duty
- 86°F
- the average summer afternoon it cools against
- 51 hail events
- in ten years, and hail bends the fins on outdoor coils
- 13.4 SEER2
- the federal minimum any new unit must meet
NOAA nClimDiv, 1991–2020 normals
Going above the federal minimum saves little here, about $10 a year.
Estimates for a typical Fairfax County home, from EIA household energy data, Virginia fuel prices and NOAA climate normals. Your home will differ.
Virginia requires HVAC contractors to hold a state license.
The Board for Contractors issues the license and keeps the record on the contractor, not on any single job. The same license covers every installation that contractor does across the state. Work under $1,000 falls outside this requirement, but a new air conditioner runs well past that line, so this installation needs a licensed contractor.
Most cities and counties in Virginia also require a permit before an air conditioner goes in, and an inspection once the work is done. That inspection is what checks this specific installation, the refrigerant lines, the electrical hookup, the unit itself. The license says the contractor is qualified. The permit and inspection say this job got checked.
Sources: Virginia General Assembly · Virginia Department of Professional and Occupational Regulation
- What size air conditioner does my house need?
- There's no single answer without a contractor measuring your house. Sizing depends on the square footage, how many windows you have and which way they face, your insulation, and your ceiling height. An undersized unit will run constantly without cooling the house on an 86°F afternoon, and an oversized one cools too fast without pulling humidity out of the air. A contractor will do a load calculation on your actual house before recommending a size.
- Should I replace the whole system or just the outdoor unit?
- In most cases you replace both the outdoor unit and the indoor coil together. The two are matched to work at a specific efficiency and capacity, and pairing a new outdoor unit with an old coil usually means you lose the efficiency gain you're paying for, and it can void the manufacturer's warranty. A contractor can look at the age and condition of your indoor coil and tell you whether it's a candidate to keep. If your system is old enough that the outdoor unit is failing, the coil is often close behind it.
- Do HVAC contractors in Herndon need a state license to work on my home?
- Yes. Virginia requires HVAC contractors to hold a state license, issued through the Board for Contractors, and installing an air conditioner falls under that requirement. The license is tied to the contractor rather than the job, so it's worth confirming before work starts. Your local building office will also require a permit for the installation and an inspection once the work is done.