Why does my AC keep turning on and off?

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AC short cycling

AC short cycling in Altamonte Springs

A system that satisfies the thermostat and shuts off within a few minutes, over and over, is usually oversized for the space, restricted by a dirty coil or filter, or hard-starting on a weak capacitor. Oversizing is a real risk in this city's smallest attached units, where it also means the house never actually dehumidifies.

What is most likely wrong

Ranked by probability

Likely causes, ranked by how often they turn out to be the answer
Cause	How common	What it looks like
1. System oversized for the space	Common in small attached units	Cools fast, shuts off within a few minutes, house feels cold but clammy rather than dry.
2. Restricted airflow or a dirty coil forcing an early safety cutoff	Common	Cycle length has been shrinking gradually rather than starting short from day one.
3. Weak run capacitor causing a hard, repeated start	Common	Audible hum or hesitation at each start; often paired with a humming-not-starting complaint elsewhere in the house.
4. Thermostat miscalibrated or badly placed	Less common	Cycling pattern changes noticeably comparing a room near the thermostat to one far from it.

What you can safely check yourself

Before you call

Time a few full cycles — on to off to on again — with a phone timer. Under about 10 minutes on, repeatedly, is short cycling.
Check the filter and the supply and return registers for obstructions.
Check what is near the thermostat: direct sun, a supply vent blowing on it, or a lamp can all fake it out.
If the house feels cold but damp rather than dry, that is a sizing symptom, not a breakdown — see how sizing is actually decided.

Where the licensed line is

A run capacitor holds a lethal charge even after the power is off. Refrigerant handling requires EPA Section 608 technician certification, and in Florida this work requires a state-licensed air conditioning contractor under Chapter 489, F.S.

Verify the licence of any contractor you hire at the DBPR licensee search.

Why this happens in Altamonte Springs

Local pattern

This city's smallest platted communities are genuinely small: Waterside at Cranes Roost runs a 496 sq ft median, Sandy Cove 633 sq ft, Oasis at Pearl Lake 674 sq ft. Equipment installed for “a two-bedroom condo” in general, rather than sized to the actual square footage and load, is a common source of short cycling in units this size — and 61.65% of this city's housing stock is multi-family, so it is not a rare case.

Seminole County Property Appraiser CAMA extract (Parcels.csv, 5 September 2026), tax district A1 — Altamonte Springs. 13,253 improved residential parcels: single-family, townhome and condominium. Apartments and manufactured homes excluded. Multi-family share: City of Altamonte Springs CITY PLAN 2030, Housing Element DIA.

What the fix typically costs

Researched ranges

Researched Orlando-market ranges, September 2026. Not this business's prices.
What is being priced	Researched range	What moves it
Diagnostic to confirm the cause	$75–$150	Orlando-market diagnostic or dispatch fee. After-hours calls commonly $150–$250.
Run capacitor	$150–$400	Florida market, parts and labour. National average around $250. Quoted metro ranges: Tampa Bay $279–$425, Cape Coral $150–$350, Naples $225–$475, Fort Lauderdale $270–$390.

Sources: Smart Home Air & Heat, Orlando repair-cost ranges (August 2026), Clear Comfort Orlando's own published prices, and for the expansion valve the Angi Orlando aggregator estimate (May 2026), the only source found for that part. Compiled September 2026. Not this business's prices.

No published Central Florida price exists for a Manual J load calculation or a right-sizing assessment on its own — where oversizing turns out to be the cause, that conversation is part of how sizing is decided, not a line item here.

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