Repair, replace, maintain
Why is my AC running but not cooling?
In Longwood's housing stock the usual order is a failed run capacitor, a condenser coil packed with oak leaf litter and pollen, a frozen evaporator from restricted return air, or a refrigerant leak. The middle two are local: shaded lots that keep a coil loaded, and 1970s plans with one central return.
Ranked by how often it's the cause
Six causes, most likely first
- Failed run capacitor. The most common single AC repair in Florida. The fan may turn but the compressor does not start, or it hums and trips. Researched range $80–$400 installed. Capacitor cost.
- Condenser coil fouled or crowded. Under mature oak and pine the outdoor coil loads with leaf litter and pollen, head pressure climbs and capacity falls. Visible from the outside, and the one thing on this list a homeowner can check safely.
- Frozen evaporator coil. Restricted return air or a clogged filter drops airflow across the coil until it ices. The system runs continuously and blows barely-cool air. Turn it to fan-only and let it thaw before anyone opens anything. Why 1970s plans do this.
- Refrigerant leak. Low charge means low capacity. On an R-410A system this is where the repair-or-replace conversation starts, because matching components now comes from pre-2025 inventory. Why that matters.
- Failing compressor. The expensive end of the list, $1,500–$3,500 out of warranty, and usually a replacement decision rather than a repair one. Priced against a changeout.
- Duct losses. If the air at the register is cold but the house is not, the capacity is going into a 130°F attic on the way. Duct work.
Safe to check yourself
Four things before you call anyone
- Check the filter. If you cannot see light through it, that is your first suspect.
- Look at the outdoor unit. Leaf litter packed into the coil fins, vegetation within a foot or two of the cabinet, or a fan that is not spinning are all visible from the garden.
- Feel the large insulated line at the outdoor unit. Ice on it means a frozen system: switch the thermostat to fan-only and let it thaw.
- Check the breaker and the float switch. An attic air handler with a full secondary pan will shut the system down on purpose.
What needs a licensed technician: anything involving refrigerant, opening the electrical compartment, or replacing a capacitor — a capacitor holds a charge after the power is off. Florida regulates air conditioning contracting under Chapter 489, and you can verify any licence at the DBPR search before you let someone work.
Sources
- HomeGuide, AC capacitor replacement cost (third-party pricing guide). https://homeguide.com/costs/ac-capacitor-replacement-cost
- Comfort Control Systems, “How Much Does AC Repair Cost in Florida?” 2026 price guide (third-party pricing guide). https://my-ccs.com/blog/how-much-does-ac-repair-cost-in-florida-2026-price-guide/
- This Old House, AC compressor cost (third-party pricing guide). https://www.thisoldhouse.com/heating-cooling/ac-compressor-cost
- U.S. EPA, HFC restrictions by sector (AIM Act Technology Transitions rule). https://www.epa.gov/climate-hfcs-reduction/hfc-restrictions-sector
- Seminole County Property Appraiser CAMA extract (Parcels.csv, dated 5 September 2026), tax district L1 — Longwood; improved residential parcels, DOR codes 01 and 04. https://www.scpafl.org/
- NOAA 1991–2020 climate normals, Orlando station. https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals
- Florida Statutes §489.105(3), definitions of Class A, B and C air-conditioning contractor. https://www.flsenate.gov/laws/statutes/2024/489.105
- Florida DBPR licensee search. https://www.myfloridalicense.com/wl11.asp
Figures are dated. Permit fees, rebate amounts and code cycles change — re-check the primary source before you rely on a number here.
Tell us what you already checked
Filter, coil, ice on the line, breaker. It shortens the visit and it stops you paying for a diagnosis you already made.