Tell us about the job
Takes about a minute. No obligation.
Sizing a central AC system for a Union County home is a local question because the compressor and condenser fan carry a sustained load across a genuine summer. Homes in Union County, MS run cooling about five months a year, from May through September. A unit that is undersized by even a small margin runs longer cycles, builds heat in the refrigerant loop, and wears the contactor faster than a correctly sized system would. Contractors here treat the load calculation as the first piece of work, not a formality, because the equipment will have little idle time to hide a poor match between the system and the house it serves.
Ductwork laid in for a previous generation of equipment shapes what a new central AC installation actually requires here. Half the homes in Union County, Mississippi were built in 1985 or earlier (2020-2024 ACS 5-year). That means a contractor sizing a new system has to walk the existing runs, check return capacity, and judge whether the duct layout moves enough air for what is going in. A mismatch there changes the scope of the job before the unit itself is ever priced. Electrical service gets the same look, since the draw of current equipment does not always match what the panel was originally set up to handle.
What Gets Installed With a New Central AC
The outdoor condenser unit sits on a concrete pad beside the house and holds the compressor and condenser coil, the two components that do the heaviest work in the system. Inside the house, the air handler mounts in a utility closet, attic, or basement and contains the blower fan and the evaporator coil, which is where the cold surface meets the indoor air.
A copper refrigerant line set runs between the outdoor and indoor units, connecting the two halves of the system through the wall or floor. The thermostat mounts on an interior wall and gives the homeowner control over when the system runs and what temperature it holds.
The drawing shows a typical layout, and a licensed contractor determines what applies to the specific configuration of your home.
Find a contractor in Union CountyUnion County, Mississippi, by the numbers
95 severe weather events were recorded in Union County, Mississippi 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 Union County, Mississippi were built in 1985 or earlier (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesUnion County, Mississippi holds 12,250 housing units (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesOwners occupy 74.7% of the occupied homes in Union County, Mississippi (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesRules & Standards Governing Central AC Installation in Union County, Mississippi9 sourced rules and standards
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.
Licensing Rules for Union County, Mississippi
Mississippi licenses residential HVAC work at every tier and at any price: a subcontractor of any tier doing heating, ventilation or air conditioning work on a residential construction or improvement project must be licensed by the State Board of Contractors no matter the dollar amount.
Severe Weather History in Union County
Storm loads put real pressure on cooling equipment, shortening cycles, stressing compressors, and driving up demand at the worst moments. What happens with the weather in Union County shapes how hard a central AC system has to work and what a contractor needs to account for when sizing and installing it.
95 severe weather events, 2015–2024. Source: NOAA National Centers for Environmental Information, Storm Events Database.