Psychrometrics is the study of the composition of air and its properties, and of the psychrometric chart used to read and calculate them. Students learn to plot dry-bulb and wet-bulb temperature, dew point, enthalpy, and absolute and relative humidity; to calculate heat content and heat index; and to use a sling psychrometer and digital instruments to take the measurements the chart depends on.
Within the SCNS taxonomy, ACR is the HVACR prefix — heating, ventilation, air conditioning and refrigeration — and the 0-level number identifies this as a postsecondary adult vocational (PSAV) clock-hour course. It carries zero college credits and is measured in 90 clock hours. It appears at approximately four Florida institutions inside HVAC/R career certificate programs, which typically total around 1,350 clock hours overall.
This is a small topical course carrying disproportionate weight. Psychrometrics is the theory that makes diagnosis possible: a technician who can read the chart can tell whether a system is actually removing moisture, whether it is oversized, whether the airflow is wrong, and whether a comfort complaint is a refrigerant problem or a duct problem. A technician who cannot is left changing parts and hoping.
Florida course inventories carry this number as ACR0061C, with the integrated-laboratory C suffix. Eastern Florida State College publishes it as ACR0061 without the C, at 90 clock hours. Daytona State's current catalog does not carry the number at all despite appearing in the statewide inventory for it.
SCNS equivalency does not cross numbers, and the suffix is part of the number. Clock-hour values in this prefix also vary sharply by the occupational completion point a course serves — related ACR courses in this repository run from 200 to 350 hours because they are whole OCP blocks, while this is a single topical unit. Read the program's own FLDOE curriculum framework rather than inferring hours from the prefix.
This is the single most consequential idea in the course for anyone who will work in this state, and it follows directly from the psychrometric chart.
An air conditioner removes moisture only while the evaporator coil is wet and the system is running. In a dry climate, the load is mostly sensible — temperature — and a slightly oversized system is merely inefficient. In Florida the load carries a very large latent component, and the consequence of oversizing is different in kind: an oversized system satisfies the thermostat quickly, short-cycles, never runs long enough to dehumidify, and leaves a house that is cold and clammy at 74 degrees and 65 percent relative humidity. The occupants then lower the thermostat, which makes it worse.
The downstream effects are real and expensive: mold and mildew growth, musty odor, condensation on registers and windows, and building material damage. Florida HVAC contractors deal with the aftermath constantly, and a substantial share of "the new unit doesn't work" complaints in this state are oversizing, not equipment failure.
The professional habits that follow: perform an actual load calculation (ACCA Manual J) rather than sizing by square footage or by matching the old unit, select equipment on sensible heat ratio and not on tonnage alone (Manual S), and verify dehumidification performance by measuring across the coil rather than by asking the customer whether it feels better. Bigger is not better here; bigger is the defect.
EPA Section 608 certification is required by federal law to purchase or handle regulated refrigerants — Type I (small appliances), Type II (high pressure), Type III (low pressure), or Universal. This is a certification, not a course grade, and it is a hiring prerequisite. Venting refrigerant to the atmosphere is a federal violation with substantial civil penalties.
The industry is mid-transition and this is a live rule-11 area. Under the federal AIM Act, high-GWP HFCs are being phased down, and new residential and light commercial equipment has been transitioning to A2L refrigerants such as R-454B and R-32. These are mildly flammable, which changes storage, transport, leak detection, service practice, and in some cases required equipment and tooling. Training material written for an R-410A world is incomplete for equipment being installed now. Verify current EPA requirements and manufacturer service procedures rather than relying on a textbook edition or on this guide.
A career-honesty point students frequently get wrong. Florida does not license individual HVAC service technicians. A technician may work for a licensed contractor without holding a state license — what is federally required is the EPA 608 certification.
Contracting is different. To pull permits, contract with the public, and operate a business, Florida requires licensure through the Construction Industry Licensing Board under Chapter 489, Florida Statutes — Class A or Class B air conditioning contractor, or a mechanical contractor license — administered by DBPR, with experience requirements, a state examination, financial responsibility, and insurance. Some counties additionally issue local licenses. Unlicensed contracting in Florida is a criminal offense and is enforced, with penalties escalating during a declared state of emergency — which matters in a hurricane state where post-storm repair work attracts unlicensed operators.
The practical path: certificate → technician employment → accumulate documented experience → contractor license. Students who want to own a business should start tracking verifiable experience from their first job, because the licensure application requires it.
ACR0061C is 90 clock hours with zero college credit. PSAV coursework does not transfer into credit programs the way a 1000- or 2000-level course does. What exists instead is articulation — Florida's Gold Standard Career Pathways and local agreements may award credit toward a related A.S. for completing an entire PSAV program or occupational completion point, not for individual courses, and not automatically. Students planning to continue into an A.S. should get a written evaluation from the receiving institution first.
In this trade, however, the certificate is not the currency. EPA 608, NATE certification, and demonstrable diagnostic ability are, and employers hire on them.
The course combines classroom chart work with hands-on measurement on operating equipment. Expect calculation-heavy assessment — plotting points, reading properties, and computing loads — alongside practical measurement exercises. Students who treat the chart as a graph to be memorized struggle; students who plot real measurements from real equipment stop finding it abstract.
Standard shop safety applies and is not incidental: measurements are frequently taken on energized, operating equipment, so lockout/tagout discipline, electrical safety, and awareness of rotating equipment matter. Rooftop and attic work in Florida adds genuine heat stress risk — attic temperatures routinely exceed 130°F, and heat illness is a real and underestimated hazard in this trade.
Generated September 2, 2026 · Updated September 2, 2026