Frozen AC coil
Frozen AC coil in Longwood, Florida
Ice on the evaporator coil or the refrigerant lines is almost always restricted airflow or low refrigerant, not a thermostat set too low. In 1970s and 80s Longwood floor plans with a single central return, airflow is already close to its limit before anything goes wrong.
Diagnosis
What is most likely wrong
| # | Cause | How common | What it looks like |
|---|---|---|---|
| 1 | Dirty or blocked air filter | Very common | The most common single cause; airflow across the coil drops until moisture on it cannot drain fast enough and ices instead. |
| 2 | Closed or blocked supply/return vents | Common | Furniture against a return grille, or vents closed to 'save' cooling in unused rooms — both starve airflow. |
| 3 | Undersized single central return | Common | Common in Longwood's 1970s and 80s plans; airflow is already tight, so a partial restriction elsewhere tips it over. |
| 4 | Low refrigerant charge from a leak | Common | The coil runs colder than it should and ices even with clean airflow. |
| 5 | Failing blower motor | Less common | Weak air movement even with a clean filter and open vents. |
| 6 | Running the system in unusually cool weather | Less common | Rare in Central Florida, but a mild snap with the thermostat set low can ice a marginal system. |
Before you call
What you can safely check yourself
- Switch the thermostat to off or fan-only and let the system thaw fully — that can take several hours. Do not run it iced; liquid refrigerant returning to the compressor can damage it.
- Check and replace the filter once it is thawed.
- Walk the house and confirm every supply and return vent is open and unobstructed.
- Once thawed and restarted, watch whether ice comes back within a few hours — that points to refrigerant or airflow rather than a one-off.
Where the licensed line is
Refrigerant, capacitors and the inside of an electrical panel are not homeowner jobs. A run capacitor holds a lethal voltage after the disconnect is pulled, and refrigerant handling requires EPA Section 608 certification. In Florida the work itself is regulated: an air conditioning contractor licensed under §489.105(3) may replace, disconnect and reconnect the power wiring at the dedicated disconnect, and repair or replace disconnects, breakers and fuses on dedicated HVAC circuits — that scope exists because this is not general-purpose electrical work.
Verify any Florida contractor’s licence before you let them start work, at the DBPR licensee search.
In Longwood
Why this happens in this housing stock
A single central return is the default in a lot of Longwood’s 1970s and 80s housing stock, and it leaves very little margin: a filter that is a week overdue, a closed vent in a back bedroom, or a piece of furniture pulled in front of the return grille is enough to tip a marginal system into icing. Why 1970s plans do this.
If the cause turns out to be a refrigerant leak on an older R-410A system, matching replacement components now comes only from remaining pre-2025 inventory, which is the point where a repeat freeze becomes a repair-or-replace question rather than a one-time fix. Why that matters.
Cost
What the fix typically costs
| What is being priced | Researched range | What moves it |
|---|---|---|
| Diagnostic visit | $75–$200 | Commonly cited Florida diagnostic or service-call fee. Some sources put Florida contractors at $65–$95, and the fee is frequently waived or credited toward the repair if the work proceeds. |
| Refrigerant leak repair | $400–$1,600 | Refrigerant leak repair and recharge; finding the leak is most of the cost. |
| Blower motor replacement | $450–$900 | Air handler blower motor, parts and labour; variable-speed/ECM motors sit at the top of the range. |
| Evaporator coil replacement | $1,500–$2,500 | Evaporator coil, parts and labour, Orlando market. |
These are researched market estimates, not a quote
Every money figure on this page is a published third-party range, compiled in September 2026 from the pricing guides listed in the sources at the foot of the page. They are here so you can sanity-check what a contractor offers you before you sign, not so you can hold anyone to a number they did not write. The one exception is the City of Longwood permit fee, which is the City's own published figure and is linked to its fee schedule.
Sources
- Smart Home Air & Heat, AC Repair Cost Orlando 2026 (Central Florida contractor, market ranges from 2025-2026 service data). https://smarthomeairheat.com/our-blog/ac-repair-cost-orlando-2026/
- 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/
- U.S. EPA, HFC restrictions by sector (AIM Act Technology Transitions rule). https://www.epa.gov/climate-hfcs-reduction/hfc-restrictions-sector
Figures are dated. Permit fees, rebate amounts and code cycles change — re-check the primary source before you rely on a number here.
Not getting anywhere?
Tell us the symptom, roughly how old the house is and roughly how old the equipment is. That usually narrows it to two candidates before anyone drives out.