Learning Center
HVAC Glossary: the terms on your quote, in plain English
A quote should not need a translator. Each term below gets a short definition, one line on why it matters in a Central Florida home, and the page where we deal with it.
- Air handler
- The indoor half of a split AC system: the blower fan and evaporator coil, usually in a closet, garage, or attic, that pulls air from the house, cools it, and pushes it back through the ducts.
- Why it matters here: Many Central Florida air handlers sit in a hot garage or attic, so leaks and poor insulation around them waste cooling before it reaches a room.
- AC Installation & Replacement
- Capacitor
- A small electrical part that gives the compressor and fan motors their starting push. It weakens with heat and age. A failed capacitor is one of the most common and least expensive AC repairs.
- Why it matters here: Florida heat is hard on capacitors; a humming outdoor unit with a fan that will not spin is a classic symptom.
- AC Repair
- CFM (airflow)
- Cubic feet per minute: how much air the system moves. A common rule of thumb is about 400 CFM per ton of cooling, with Florida's humid climate often calling for slightly less to improve moisture removal.
- Why it matters here: Too little airflow freezes coils; too much leaves humidity in the air. Balancing CFM is part of fixing a hot room.
- Why Is One Room Hotter Than the Rest?
- Compressor
- The pump at the heart of the outdoor unit that circulates refrigerant. It is the single most expensive part of a system, which is why a failed compressor is the classic repair-or-replace decision.
- Why it matters here: Before you approve a compressor replacement, check the manufacturer warranty and get a second opinion. Both are free with us.
- Should I Repair or Replace My AC?
- Condensate drain line
- The PVC pipe that carries the water your AC pulls out of the air to a drain or outside. When it clogs with algae or sludge, water backs up and the safety switch shuts the system down.
- Why it matters here: A clogged drain is one of the most common summer no-cooling calls in Central Florida. Flushing it is part of every tune-up.
- AC Maintenance
- Condenser (outdoor unit)
- The outdoor cabinet with the compressor, condenser coil, and fan. It releases the heat pulled out of your home. Keeping its coil clean and its airflow clear is most of AC maintenance.
- Why it matters here: Lawn clippings, grass, and pollen clog outdoor coils fast here, so a yearly coil cleaning does real work in Florida.
- AC Maintenance
- Contactor
- The electrical relay that switches high-voltage power to the outdoor unit when the thermostat calls for cooling. Pitted or stuck contacts can keep a unit from starting, or from stopping.
- Why it matters here: Checking contactor condition is part of our maintenance visit.
- AC Maintenance
- Duct leakage
- Cooled air escaping through gaps, loose joints, or torn flex duct before it reaches a room. Leaky supply ducts in an attic dump paid-for cooling into unconditioned space.
- Why it matters here: Attic ducts here sit in air far hotter than the outdoors all summer, so even small leaks hurt. Sealing and repair are usually far cheaper than replacement.
- Duct Repair
- Ductless mini-split
- A system with an outdoor unit and one or more wall- or ceiling-mounted indoor heads connected by refrigerant lines, with no ductwork. Each head conditions its own zone with its own setting.
- Why it matters here: Garages, sunrooms, additions, and that one bedroom the ducts never reached are where mini-splits earn their keep locally.
- Ductless Mini-Split Installation
- Evaporator coil
- The indoor coil inside the air handler. Refrigerant inside it absorbs heat and moisture from the air passing over it. When airflow drops, the coil can freeze into a block of ice.
- Why it matters here: A frozen coil in July is usually restricted airflow (a dirty filter or blocked return) or low refrigerant, not a reason to replace the system.
- AC Repair
- Float switch
- A small safety switch in the drain pan or line that turns the system off when water backs up, so it cannot overflow into your ceiling or closet. A tripped float switch is a drain problem, not a dead AC.
- Why it matters here: If your AC stopped and the thermostat looks fine, check for water in the pan before you assume the worst.
- AC Repair
- Heat pump
- An air conditioner that can run in reverse to heat the house, moving heat from outside air indoors. In a mild climate it heats far more efficiently than electric resistance heat.
- Why it matters here: Most heating in Central Florida homes is a heat pump or electric heat strips, not a furnace. If your "heater" is also your AC, you have a heat pump.
- Heat Pump Service
- Heat strips (auxiliary heat)
- Electric resistance coils inside the air handler that provide backup or emergency heat. They work like a giant toaster and cost several times more per hour to run than the heat pump itself.
- Why it matters here: If your winter bill spikes on cold mornings, the heat strips are probably running longer than they should. That is worth a service call.
- Heating Repair
- Manual D (duct design)
- The companion method for sizing and laying out ductwork so each room gets the airflow the Manual J says it needs. Right-sized equipment on wrong-sized ducts still leaves hot rooms.
- Why it matters here: Many Florida homes have ducts that were sized for a smaller system or added to over the years. Manual D is how a redesign fixes that.
- Duct Redesign
- Manual J (load calculation)
- The industry method for sizing an AC system. It accounts for your home's square footage, insulation, windows, orientation, and local climate to find the cooling load in BTU per hour.
- Why it matters here: We include a Manual J with every free replacement estimate. A quote without one is a guess.
- What Size AC Does My Home Need?
- Manufacturer warranty
- The equipment maker's coverage on parts, often up to ten years when the system was registered after installation. It usually covers parts only; labor is a separate warranty from the installer.
- Why it matters here: Homeowners are regularly told a warranty has expired when it has not. We look it up from the serial number, free, before you approve a big repair.
- Is My AC Still Under Warranty?
- MERV rating
- Minimum Efficiency Reporting Value: how well an air filter captures particles. Home filters typically run MERV 1 to 16 (the scale goes to 20). Higher catches smaller particles but also restricts airflow more.
- Why it matters here: Jumping to a very high-MERV filter without checking the system's static pressure is a common way to create a frozen coil.
- Indoor Air Quality
- Permit and final inspection
- Most jurisdictions require a mechanical permit for a system replacement and a final inspection once it is installed. The permit protects you by putting a code inspector's eyes on the work.
- Why it matters here: We pull required permits where the jurisdiction requires them and coordinate the final inspection with you and the county or city. Requirements vary by municipality; confirm current rules with your local building department.
- AC Installation & Replacement
- Plenum
- The sheet-metal or duct-board box attached to the air handler that all the main ducts branch from. There is a supply plenum (air going out) and a return plenum (air coming back).
- Why it matters here: A crumbling duct-board plenum is a common find during an install in older Kissimmee and St. Cloud homes.
- Duct Replacement & Installation
- Preventive maintenance (tune-up)
- A scheduled visit to clean coils, flush the drain, check refrigerant charge and electrical parts, and test airflow before a failure happens. Many manufacturers expect it to keep a warranty valid.
- Why it matters here: Our Family Comfort Plan covers two visits a year.
- Family Comfort Plan
- R-value (insulation)
- A measure of how well insulation resists heat flow. Higher R-value means more resistance. Attic insulation is rated by total depth, so settled or thin insulation loses R-value over time.
- Why it matters here: A thin attic lets summer heat radiate straight down into the house, so the AC runs longer. Topping up attic insulation is one of the cheaper comfort fixes here.
- Blown-In Attic Insulation
- Refrigerant (R-22, R-410A, R-454B)
- The fluid that carries heat out of your home. Older systems use R-22 (no longer produced), most current ones R-410A, and new 2025-era systems lower-impact refrigerants such as R-454B or R-32.
- Why it matters here: A system that keeps needing refrigerant has a leak. Topping it off every summer is not a repair, and on an R-22 unit it is expensive money spent on obsolete equipment.
- AC Repair
- Relative humidity (indoor)
- How much moisture the air holds compared with the maximum it could hold at that temperature. Common guidance puts comfortable indoor humidity between about 30 and 50 percent; above 60 percent the air feels sticky and mold gets a foothold.
- Why it matters here: Humidity control is half of comfort in Central Florida. A system that short-cycles or is oversized cools the air but leaves it sticky.
- What Size AC Does My Home Need?
- Second opinion
- An independent diagnosis from another licensed contractor before you approve a major repair or a replacement. It confirms what actually failed and whether a warranty applies.
- Why it matters here: Ours is free, and so is the written estimate that comes with it.
- Free Second Opinion
- SEER2
- Seasonal Energy Efficiency Ratio, version 2: cooling output divided by electricity used over a season, measured under the 2023 test procedure. A higher number means lower cooling bills for the same comfort.
- Why it matters here: The federal minimum for a new residential split air conditioner under 45,000 BTU/h installed in the Southeast, including Florida, is 14.3 SEER2; larger and packaged systems have their own minimums. Because our systems run most of the year, efficiency pays back faster here than up north.
- AC Installation & Replacement
- Static pressure
- The resistance the blower fights to push air through the filter, coil, and ducts. Measured in inches of water column. High static pressure means the system is straining, which shortens its life.
- Why it matters here: Undersized returns and restrictive filters are the usual causes we find in local homes. An airflow test measures it in minutes.
- Airflow Testing
- Ton / BTU
- Cooling capacity. One ton of cooling equals 12,000 BTU per hour. A home's correct tonnage comes from a Manual J load calculation, not from square footage alone or the old unit's nameplate.
- Why it matters here: Oversized systems are common in Central Florida. They cool fast, shut off early, and leave the humidity behind, so the house feels clammy.
- What Size AC Does My Home Need?
- UV light (coil UV)
- An ultraviolet lamp mounted near the evaporator coil to keep mold and bacteria from growing on the wet coil surface. It treats the coil, not the whole airstream.
- Why it matters here: Our humid climate keeps indoor coils wet nearly year-round, which is exactly the condition a coil UV light is built for.
- UV Light Installation
