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Sizing a central AC system in DeKalb County means accounting for a climate that puts real, recurring load on equipment. 165 severe weather events were recorded in DeKalb County, Georgia between 2015 and 2024. At that rate, severe weather is part of the normal operating environment, and a contractor who ignores it when calculating capacity and selecting equipment is quoting for a place that does not exist. The ductwork, the refrigerant lines, the unit itself all have to be matched to what the system will actually run against here, not to a regional average.
Ductwork sized and routed for older equipment is what a contractor has to assess before a new central AC system can be priced accurately. Half the homes in DeKalb County, Georgia were built in 1984 or earlier (2020-2024 ACS 5-year). A house built then was ducted for the units of that period, and the trunk lines, branches, and returns may not move enough air for what runs now. Electrical service is a second check: the panel capacity and the circuit run to the condenser pad have to match what a modern unit draws. Both have to be confirmed on site.
What Gets Installed With a New Central AC
The outdoor condenser unit sits on a pad outside the house and holds the compressor and condenser coil, which are the core of the system. Inside, the air handler or furnace cabinet stands in a utility space, basement, or closet and circulates air through the home. Together these two cabinets make up the working heart of a central AC installation.
A copper refrigerant line set runs between the two cabinets, connecting the indoor and outdoor units through the wall or floor. The thermostat mounts on an interior wall and gives the homeowner control over when the system runs. A condensate drain line also runs from the air handler to carry away the moisture the coil pulls from indoor air.
The drawing shows a typical layout, and a licensed contractor determines exactly how each piece fits the configuration of your house.
Get matched in DeKalb CountyDeKalb County by the Numbers
165 severe weather events were recorded in DeKalb County, Georgia between 2015 and 2024.
NOAA National Centers for Environmental Information, Storm Events Database, bulk CSV export, events 2015-01-01 through 2024-12-31.Half the homes in DeKalb County, Georgia were built in 1984 or earlier (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesDeKalb County, Georgia holds 330,830 housing units (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesOwners occupy 58.8% of the occupied homes in DeKalb County, Georgia (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesRules & Standards Behind Central AC Installation in DeKalb County, Georgia8 sourced regulations and codes
What the installation actually looks like
Split-system central air conditioners rated below 45,000 Btu/h manufactured on or after January 1, 2023 must meet a federal minimum of 13.4 SEER2.
Split-system central air conditioners rated at or above 45,000 Btu/h manufactured on or after January 1, 2023 must meet a federal minimum of 13.4 SEER2.
Split-system central air conditioners manufactured between January 1, 2015 and December 31, 2022 had to meet 13 SEER, the metric that preceded SEER2.
Single-package central air conditioners manufactured on or after January 1, 2023 must meet a federal minimum of 13.4 SEER2.
Space-constrained central air conditioners manufactured on or after January 1, 2023 must meet a federal minimum of 11.7 SEER2.
Federal efficiency standards for split-system central air conditioners and heat pumps are set on each certified combination of outdoor unit and indoor coil rather than on the outdoor unit alone.
Residential and light commercial air conditioning and heat pump systems assembled in the field, including mini-splits and unitary systems, may not be installed on or after January 1, 2025 using a refrigerant with a global warming potential above 700.
A field-assembled system whose specified components were all manufactured or imported before January 1, 2025 carries no installation compliance date under the refrigerant restrictions and may still be installed.
Severe Weather Events in DeKalb County
Georgia's climate puts real stress on cooling equipment, and DeKalb County gets its share of that load. How hard a system has to work, and how often it runs at its limits, is shaped by local conditions, which is why the weather record here matters when you are sizing and installing central AC.
165 severe weather events, 2015–2024. Source: NOAA National Centers for Environmental Information, Storm Events Database.