AC Equipment Inspection: What to Check Before Summer

A working AC and a healthy AC are not the same thing. By the time most homeowners call us, the system has been showing warning signs for weeks. This guide walks through your equipment component by component — what to look at, what's normal, and what needs a technician. Do this once in May and you'll know exactly where you stand for the summer.

The Outdoor Condenser Unit

Start here. The condenser sits in the worst spot in your yard — full sun, salt air if you're near the coast, and at the mercy of every thunderstorm. Walk around it and check:

Physical Condition

• Coil fins: Look at the metal fins wrapping the unit. Bent or matted fins reduce airflow and efficiency. Mild bending is normal; large flattened sections need a fin comb (or a tech).
• Rust: Surface rust on the cabinet is cosmetic. Rust at the base, on the coil, or around the refrigerant line connections is a problem — especially within 5 miles of the ocean.
• Level: The unit should sit level on its pad. A tilted unit stresses the compressor and can affect refrigerant oil return.
• Clearance: 24 inches minimum on the sides, 60 inches above. Vegetation, fences, and AC covers all choke airflow.

Electrical Disconnect

Next to the condenser is a small gray box — the disconnect. Open it. You should see a pull-out fuse or a switch in good condition. Look for:

• Burn marks or melted plastic (call us immediately)
• Wasp or ant nests (very common in Miami)
• Loose or corroded wire terminals
• A surge protector — if there isn't one, install one before storm season

The Indoor Air Handler

Usually in a closet, attic, or garage. Pop the access panel (with the system off and breaker pulled) and look at:

The Evaporator Coil

This is the A-shaped or N-shaped coil where cooling happens. It should be clean and silver-colored. Warning signs:

• Brown or black dust caked on the front face — restricts airflow severely
• White or green slime — biological growth, common in humid climates
• Oily residue — possible refrigerant leak
• Ice anywhere on the coil or refrigerant lines — shut system off and call

The Blower Compartment

The blower wheel sits below or beside the coil. With power off, shine a light on it. The blades should be reasonably clean. A blower wheel caked with dust loses 20–30% of its airflow capacity — which cascades into frozen coils, long run times, and high humidity inside the home.

The Drain Pan

Underneath the coil is a metal or plastic drain pan. It should be dry or have a thin film of moisture. Standing water means the drain line is partially blocked. Rust stains, biological growth, or visible cracks mean the pan needs attention — a leaking secondary pan is one of the most common causes of ceiling damage in Florida.

The Ductwork

If your ducts are in the attic (typical in South Florida), this matters enormously. Attic temperatures in June–September regularly hit 130°F. Any leak or insulation gap turns into cooled air dumped into the attic — which you pay for.

• Insulation: Should be intact, with no exposed metal or flex duct visible. Look for compressed, torn, or animal-damaged sections.
• Joints and seams: Tape often fails over time. Mastic sealant lasts much longer.
• Flex duct condition: Should be supported every 4 feet and not sagging or kinked. A pinched flex duct can cut airflow in half to that room.
• Disconnections: Yes, this happens — a flex duct simply pops off the plenum. A dead room with no airflow is the giveaway.

Vents and Returns

Walk every room with the system running. At each supply vent, you should feel strong, cold air. At each return, you should feel strong suction. Note any room that's noticeably warmer or has weak airflow — that's diagnostic information your tech needs.

• Remove and vacuum return grilles — dust buildup here measurably reduces system airflow
• Check that nothing is blocking vents (furniture, rugs, curtains)
• Don't close vents in unused rooms — modern systems are designed for the full duct system to be open

The Thermostat

• Mounted on an interior wall, away from direct sun, supply vents, and kitchen heat sources
• Reading within 1–2°F of an independent thermometer placed next to it
• Fresh batteries if applicable
• Up-to-date schedule and Wi-Fi connection if it's a smart model

System Performance Test

With everything inspected, run a 20-minute cooling test:

1. Set thermostat 5°F below current room temperature
2. After 15 minutes, measure supply vent temperature with a probe thermometer
3. Measure return air temperature at the return grille
4. The temperature difference (Delta T) should be 18–22°F

If Delta T is below 16°F or above 24°F, something is wrong — typically refrigerant charge, airflow, or both.

What Needs a Professional

These are not DIY checks and require gauges, meters, and training:

• Refrigerant superheat and subcool measurement
• Capacitor microfarad testing
• Compressor amp draw and start-up characteristics
• Contactor inspection and electrical connection torque
• Static pressure testing across the air handler
• Combustion or heat strip testing on the heating side

If your homeowner inspection turns up anything concerning — or if you simply want the peace of mind heading into summer — book a tune-up. We'll cover everything above plus the items only a tech can measure, typically in under 90 minutes.