South Carolina HVAC Match
An outdoor air conditioning condenser unit mounted on a concrete pad next to a blue-sided residential house at sunset.

AC Installation in Charleston, SC

A new air conditioner in Charleston will run from May through October every year. Tell us about the house, and a licensed contractor who covers Charleston County will get in touch.

Tell us about the job

It takes about a minute.

Step 1 of 3: Equipment
An outdoor air conditioning condenser unit positioned beside a blue-sided house at sunset.

Six months of cooling, and afternoons near 89

A new air conditioner in Charleston County runs May through October. That is six months of the compressor cycling on, most afternoons, with summer highs averaging 89°F.

Any new central air conditioner installed today has to meet 14.3 SEER2, the federal minimum since 2023. Charleston County has also logged 304 damaging wind events and 61 hail events over the past ten years, with hail up to 1.75 inches. Whoever installs your outdoor unit should account for that when they place and secure it.

6 months
May through October, your air conditioner is on duty
89°F
the average summer afternoon it cools against
61 hail events
in ten years, and hail bends the fins on outdoor coils
13.4 SEER2
the federal minimum any new unit must meet
Isometric grayscale illustration of a cutaway house interior showing a furnace with ductwork, interior rooms with furniture, and an outdoor condenser unit connected by lines at the exterior wall.
Your air conditioner works hardest from June through September.

NOAA nClimDiv, 1991–2020 normals

Aerial view of a square outdoor air conditioning condenser unit on a concrete pad beside a house wall with a sliding glass door.

Going above the federal minimum saves little here, about $20 a year.

  • A higher-efficiency unit$430 a year
  • A new unit at the federal minimum, 14.3 SEER2$450 a year

Estimates for a typical Charleston County home, from EIA household energy data, South Carolina fuel prices and NOAA climate normals. Your home will differ.

What size air conditioner does my house need?
There's no single number that fits every house. Sizing depends on your square footage, ceiling height, insulation, and how much sun the house takes through the afternoon. A contractor works this out with a load calculation, not a rule of thumb, because a unit that's too big cools the air fast but leaves the house damp, and one that's too small runs constantly without keeping up.
Should I replace the whole system or just the outdoor unit?
If the indoor and outdoor units are original to each other, replacing just the outdoor unit usually isn't the better move. The two are matched to work as a pair, and pairing a new outdoor unit with an old indoor coil can mean it never runs at the efficiency it's rated for, sometimes voiding the warranty on the new part outright. A contractor can check the age and condition of both and tell you whether the coil is worth keeping. Homes here run the AC six months a year, May through October, so a mismatched system has a lot of hours to show the strain.
Do HVAC contractors in Charleston need a state license to work on my home?
A contractor should be able to show you a current license before any work starts. Ask to see it, and if you have doubts, you can confirm it's valid before agreeing to the job. This matters most on an install, since the equipment going in has to meet the federal minimum of 14.3 SEER2, and you want someone who knows how to size and set up the system to actually hit that.
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