HVAC Glossary
100+ HVAC terms defined for the Philippine market.
Core Concepts
BTU (British Thermal Unit)
The standard measurement of cooling capacity. One BTU is the energy needed to raise one pound of water by 1°F. A 1.0 HP aircon produces approximately 9,000 BTU/h of cooling.
HP (Horsepower)
Aircon capacity rating used in the Philippines. 1 HP ≈ 9,000 BTU/h. Common residential sizes: 0.75 HP (small bedroom), 1.0 HP (master bedroom), 1.5 HP (living room), 2.0 HP (large spaces).
EER (Energy Efficiency Ratio)
Cooling output (BTU/h) divided by power input (Watts). Higher EER = lower electricity cost. Philippine 5-star rating requires EER of 12.0+. Top brands like Daikin achieve 14.0–15.5.
SEER (Seasonal EER)
Average efficiency measured across an entire cooling season rather than a single test point. Accounts for varying temperatures and part-load conditions. More accurate than EER for real-world savings.
COP (Coefficient of Performance)
Ratio of cooling output to energy input, measured in watts. COP of 3.0 means 3 watts of cooling per 1 watt of electricity consumed. Used internationally alongside EER.
Cooling Load
The total amount of heat that must be removed from a space to maintain the desired temperature. Calculated using room size, insulation, occupancy, equipment, and solar heat gain.
Ton of Refrigeration (TR)
A unit of cooling capacity equal to 12,000 BTU/h. Commonly used for commercial HVAC sizing. A typical 1.0 HP residential unit is approximately 0.75 TR.
CFM (Cubic Feet per Minute)
Measures airflow volume — how much air the unit moves per minute. Higher CFM means faster air distribution across the room. Important for large open-plan spaces.
Superheat
The temperature of refrigerant gas above its boiling point at a given pressure. Technicians measure superheat at the evaporator outlet to verify correct refrigerant charge — too high indicates undercharge.
Subcooling
The temperature of liquid refrigerant below its condensing point at a given pressure. Measured at the condenser outlet to verify correct refrigerant charge — too low indicates undercharge or restriction.
Sensible Heat
Heat that changes the temperature of air without changing its moisture content. Removing sensible heat makes the space feel cooler. The sensible heat ratio (SHR) indicates how much of an AC's capacity handles sensible vs. latent heat.
Latent Heat
Heat associated with moisture removal (dehumidification) rather than temperature change. Critical in the Philippines where humidity (70-85% RH) contributes significantly to discomfort and indoor air quality issues.
Wet Bulb Temperature
The lowest temperature achievable by evaporative cooling — measured with a wetted thermometer. Used to size cooling towers and evaluate chiller performance. Philippine wet bulb temperatures average 27-29°C.
Dry Bulb Temperature
The standard air temperature measured by a thermometer not affected by moisture. The temperature shown on your aircon remote. Philippine dry bulb temperatures reach 35-38°C during summer months.
Aircon Types
Split Type
Two-piece system with an indoor wall-mounted evaporator and outdoor compressor connected by copper piping. Most popular type in Philippine homes. Quiet operation (19-26 dB), flexible placement.
Window Type
Self-contained single unit installed through a wall or window opening. More affordable than split type but louder (50-65 dB). Common in Philippine apartments and budget installations.
Cassette Type
Ceiling-recessed commercial unit that distributes air in 2 or 4 directions through a decorative panel. Used in offices, restaurants, and retail spaces. Requires false ceiling.
Floor Standing
Tall vertical unit placed on the floor, resembling a tower. High cooling capacity (3–5 HP) for large spaces. Common in Philippine function halls, churches, and open offices.
Ceiling Suspended
Unit mounted on the ceiling without recessing. Ideal for commercial spaces without false ceilings. Provides wide airflow coverage for warehouses and workshops.
Precision Aircon
Specialized cooling system designed for data centers, server rooms, and telecom facilities. Maintains exact temperature (±0.5°C) and humidity (±2% RH) for sensitive electronic equipment.
Multi-Split System
One outdoor unit connected to multiple indoor units (2–5). Each indoor unit can be controlled independently. Ideal for homes or offices needing cooling in several rooms with limited outdoor space.
VRF / VRV System
Variable Refrigerant Flow — large-scale commercial system connecting one outdoor unit to 20–60+ indoor units. Daikin invented VRV technology in 1982. Used in Philippine malls, hotels, and high-rise buildings.
Portable Aircon
Movable unit on wheels with an exhaust hose vented through a window. No permanent installation needed. Lower efficiency than split or window types but useful for temporary cooling.
Ductless Mini-Split
Another term for a residential split-type system, emphasizing the absence of ductwork. Common terminology in international markets. Functionally identical to the Philippine 'split-type aircon.'
Heat Pump
An aircon that can reverse its refrigerant cycle to provide both cooling and heating. Rarely needed in the Philippine tropical climate but useful for high-altitude installations in Benguet or Bukidnon.
Technology & Features
Inverter Technology
Variable-speed compressor that adjusts power based on cooling demand instead of cycling on/off. Saves 30–50% on electricity, runs quieter, and maintains more stable room temperature. Standard on premium units.
Non-Inverter (Fixed Speed)
Traditional compressor that runs at one speed — full power on, then completely off. Cheaper upfront but uses more electricity through constant start-stop cycling. Still common in budget window types.
Dual Inverter
LG's twin-rotary compressor technology that reduces vibration, noise, and energy use. The dual mechanism provides smoother operation and greater durability than single-rotary inverter compressors.
R32 Refrigerant
Eco-friendly refrigerant with 67% lower global warming potential than R410A. Provides approximately 10% better energy efficiency. Now standard on most new inverter units sold in the Philippines.
R410A Refrigerant
Previous-generation refrigerant that replaced ozone-depleting R22. Non-toxic and non-flammable. Still used in many existing units but being phased out in favor of R32 for environmental reasons.
R22 Refrigerant (Freon)
Older refrigerant being phased out globally due to ozone depletion. Still found in aircon units manufactured before 2015. Recharging R22 is increasingly expensive as supply dwindles.
Wi-Fi Control
Built-in wireless connectivity allowing control via smartphone app. Set schedules, adjust temperature remotely, and monitor energy consumption. Available on Samsung (SmartThings), LG (ThinQ), Daikin (D-Mobile).
Nanoe-X (Panasonic)
Air purification technology using hydroxyl radicals to inhibit bacteria, viruses, mold, allergens, and odors. Generates nano-sized water particles that penetrate fabric and surfaces.
Wind-Free (Samsung)
Technology delivering gentle, draft-free cooling through 23,000 micro-holes once the set temperature is reached. Prevents the uncomfortable cold blast feeling while maintaining efficiency.
Turbo / Jet Mode
High-speed cooling mode that runs the compressor and fan at maximum output for rapid temperature drop. Useful when entering a hot room. Available on most inverter models from all brands.
Sleep Mode / Timer
Gradually raises the set temperature by 1–2°C during sleep hours to save energy without noticeable comfort change. Most units also have programmable on/off timers.
Self-Cleaning / Auto-Clean
Feature that automatically dries the evaporator coil after operation to prevent mold and bacteria growth. Reduces cleaning frequency. Available on Samsung, Panasonic, and Daikin models.
Econavi (Panasonic)
Sensor-based energy saving technology that detects human presence and sunlight intensity, automatically adjusting cooling output to match actual room conditions. Reduces energy use by up to 30%.
Flash Streamer (Daikin)
Daikin's air purification technology that uses streamer discharge to decompose allergens, bacteria, and viruses on the filter before they circulate in the room.
Components & Parts
Compressor
The heart of an aircon system — a motor-driven pump that circulates refrigerant through the cooling cycle. Most expensive component to replace (₱8,000–₱25,000). Warranty ranges from 5 years (Carrier) to 12 years (Panasonic).
Evaporator Coil
The indoor coil (heat exchanger) where liquid refrigerant absorbs heat from room air and evaporates into gas. Must be professionally cleaned every 3–4 months to prevent efficiency loss and mold growth.
Condenser Coil
The outdoor coil where hot refrigerant gas releases absorbed heat to the outside air and condenses back to liquid. Keep clear of walls, plants, and obstructions for proper heat dissipation.
PCB (Printed Circuit Board)
The electronic control board that manages temperature sensing, compressor speed, fan control, and error diagnostics. Sensitive to power surges; use an AVR for protection.
Blower Fan / Fan Motor
The indoor fan that draws room air across the evaporator coil and distributes cooled air. A failing blower produces weak airflow, unusual noises, or vibration. Replacement costs ₱2,500–₱5,000.
Copper Piping
Insulated copper tubes connecting indoor and outdoor units, carrying refrigerant in both liquid and gas phases. Standard installation includes up to 10 feet. Additional piping costs ₱350–₱500 per foot.
Drain Pan & Line
Collects condensation from the evaporator coil and routes it outside. Clogged drain lines are the #1 cause of water leaking from indoor units in Philippine homes. Clean every 3 months.
Air Filter
Mesh screen that traps dust, pollen, and particles before air passes over the evaporator coil. Should be cleaned every 2–3 weeks during heavy use (March–June in the Philippines).
Expansion Valve
Controls the flow of liquid refrigerant into the evaporator coil, reducing its pressure and temperature before it absorbs room heat. A malfunctioning valve causes poor cooling or ice buildup.
Capacitor
Electrical component that stores and releases energy to start the compressor and fan motors. A common failure point in older units — symptoms include the unit not turning on or humming without starting.
Thermistor / Temperature Sensor
Electronic sensor that measures room and coil temperatures, sending data to the PCB to regulate compressor speed and fan output. Faulty sensors cause inaccurate temperature readings.
Louver / Swing Vane
Adjustable horizontal and vertical flaps that direct airflow direction. Motorized louvers automatically sweep for even air distribution. Manual override is available on most remote controls.
Refrigerant Charge
The specific amount of refrigerant gas required for a system to operate at rated efficiency. Under- or overcharging damages the compressor. Proper charge is verified by measuring superheat and subcooling.
Commercial Systems
Chiller
Large-scale cooling plant that produces chilled water distributed through pipes to air handling units (AHUs) throughout a building. Used in Philippine malls, hospitals, and high-rise commercial buildings.
AHU (Air Handling Unit)
Large unit that conditions and distributes air through ductwork in commercial buildings. Contains filters, coils, and fans. Works with chiller systems to cool entire floors or zones.
FCU (Fan Coil Unit)
Smaller unit connected to a chilled water system, used to cool individual rooms or zones in commercial buildings. Common in Philippine hotels and office buildings.
BMS (Building Management System)
Computer-based control system that monitors and manages a building's HVAC, lighting, and electrical systems. Carrier and Daikin cassette units offer BMS-ready connectivity.
Ducted System
Concealed HVAC system where conditioned air is distributed through metal or fabric ducts hidden above false ceilings. Provides uniform cooling across large open spaces without visible indoor units.
Package Unit
Self-contained commercial cooling system where all components (compressor, condenser, evaporator) are housed in a single outdoor cabinet. Ducted to interior spaces. Common for Philippine warehouses and factories.
Clean Room HVAC
Specialized system maintaining controlled particle counts, temperature, and humidity for pharmaceutical, semiconductor, and food manufacturing facilities. Requires HEPA filtration and positive pressure.
CRAC (Computer Room AC)
Computer Room Air Conditioning — specialized precision cooling designed for IT environments. Provides constant temperature and humidity with high sensible heat ratio.
Hot/Cold Aisle Containment
Data center airflow management strategy that separates hot exhaust air from cold supply air using physical barriers. Increases precision aircon efficiency by 20–40%.
Cooling Tower
Evaporative heat rejection device used with water-cooled chillers to dissipate heat to the atmosphere. Typically mounted on the roof. Requires regular water treatment to prevent Legionella growth.
BACnet
A data communication protocol for building automation and control networks (ASHRAE Standard 135). Allows HVAC equipment from different manufacturers to communicate with a building management system.
Modbus
A serial communication protocol widely used in HVAC and industrial automation. Many commercial aircon units (Daikin, Mitsubishi) support Modbus for integration with BMS and energy monitoring systems.
Fabric Duct
Textile-based air distribution system made from permeable or micro-perforated fabric replacing traditional metal ductwork. Provides even, draft-free air distribution. Lighter, faster to install, and easier to clean.
Ventilation & IAQ
IAQ (Indoor Air Quality)
The quality of air inside buildings, including temperature, humidity, CO2 levels, particulates, and VOC concentration. Poor IAQ causes drowsiness, allergies, and sick building syndrome — increasingly regulated in Philippine offices post-COVID.
ERV (Energy Recovery Ventilator)
Ventilation device that exchanges stale indoor air with fresh outdoor air while recovering 70-80% of the cooling (or heating) energy. Reduces AC load while maintaining fresh air requirements.
ACH (Air Changes per Hour)
The number of times the total air volume in a room is replaced in one hour. Hospitals require 6-15 ACH for patient rooms; standard offices target 4-6 ACH. Higher ACH improves IAQ but increases energy use.
MERV Rating
Minimum Efficiency Reporting Value — a scale (1-16) measuring how effectively an air filter captures particles of various sizes. MERV 8 captures dust and mold; MERV 13+ captures bacteria and fine particles.
HEPA Filter
High-Efficiency Particulate Air filter — captures 99.97% of particles 0.3 microns or larger. Used in hospitals, clean rooms, and precision environments. Equivalent to MERV 17-20.
Static Pressure
Resistance to airflow in a duct system, measured in Pascals or inches of water column (in. WC). Higher static pressure requires more powerful fan motors. Critical for AHU and ducted system design.
CO2 Monitoring
Measuring indoor carbon dioxide levels as a proxy for ventilation adequacy. ASHRAE recommends keeping CO2 below 1,000 ppm. Levels above 1,500 ppm cause noticeable cognitive impairment.
Dehumidifier
Appliance that removes moisture from air without necessarily cooling it. Essential in Philippine storage rooms, archives, server rooms, and basements where humidity causes mold and equipment damage.
VOC (Volatile Organic Compound)
Gaseous chemicals emitted by paints, adhesives, cleaning products, and furniture. Common indoor air pollutants in newly constructed Philippine buildings. Some aircon purification systems (Nanoe-X, Flash Streamer) decompose VOCs.
Positive Pressure
Maintaining indoor air pressure slightly above outdoor pressure to prevent unfiltered air infiltration. Required in hospital operating rooms, pharmaceutical clean rooms, and food processing facilities.
Negative Pressure
Maintaining indoor air pressure below outdoor pressure to contain airborne contaminants within the space. Used in hospital isolation rooms and laboratory biosafety cabinets.
Psychrometric Chart
A graph that shows the thermodynamic properties of moist air (temperature, humidity, enthalpy, dew point). HVAC engineers use psychrometric charts to design cooling and dehumidification systems.
Services & Maintenance
PMP (Preventive Maintenance Plan)
Scheduled regular servicing to maintain aircon efficiency and extend lifespan. Typically quarterly for residential and monthly for commercial. Mr. Aircon's PMP starts at ₱1,200 per visit.
Deep Cleaning
Professional disassembly and thorough cleaning of evaporator coil, blower fan, drain pan, and filters using specialized coil cleaner. Recommended every 3–4 months in the Philippines. Takes 45–60 minutes per unit.
Chemical Wash
Intensive cleaning using chemical solutions to dissolve stubborn buildup on evaporator and condenser coils. Required when standard deep cleaning cannot restore cooling performance or eliminate odors.
Refrigerant Recharge
Adding refrigerant gas (R32 or R410A) to restore the system's cooling capacity. Low refrigerant indicates a leak that must be located and repaired first. Mr. Aircon charges from ₱3,800.
Vacuum Pump Test
Essential step during installation where a vacuum pump removes air and moisture from the copper piping before releasing refrigerant. Skipping this step causes contamination and premature compressor failure.
Leak Detection
Process of locating refrigerant leaks using electronic leak detectors, UV dye, or nitrogen pressure testing. Common leak points: flare connections, copper piping joints, and evaporator/condenser coils.
Compressor Overhaul
Major repair involving disassembly, inspection, and replacement of worn internal components (valves, bearings, gaskets) in the compressor. An alternative to full compressor replacement at lower cost.
Site Survey
Pre-installation assessment where a technician measures room dimensions, checks wall type, evaluates electrical capacity, and determines optimal unit placement. Mr. Aircon provides free site surveys in Metro Manila and Cebu.
AVR (Automatic Voltage Regulator)
Device that stabilizes voltage supply to the aircon, protecting the sensitive inverter board from power fluctuations common in Philippine electrical grids. Strongly recommended for inverter units.
Annual Maintenance Contract (AMC)
A service agreement covering scheduled preventive maintenance visits for commercial HVAC installations. Typically includes 4-12 visits per year, priority response times, and discounted repair rates.
Installation
Back-to-Back Installation
Setup where the indoor and outdoor units are mounted on opposite sides of the same wall. Minimizes copper piping length and cost. The simplest and most affordable installation type.
Side Piping
Routing copper pipes from the indoor unit sideways along the wall to reach the outdoor unit positioned around a corner or on a different wall. Requires additional piping and concealment work.
Trunking / Casing
PVC or metal cover used to conceal exposed copper pipes and drainage lines along walls and ceilings. Provides a clean appearance. Standard trunking costs ₱300–₱500 per meter.
Flare Connection
The brass fitting where copper tubing connects to the indoor and outdoor units. Must be properly tightened to prevent refrigerant leaks. The most common source of installation-related leaks.
Drain Pump
Small electric pump installed when the indoor unit is positioned below the available drain line exit point. Pumps condensation upward against gravity. Adds ₱2,500–₱4,000 to installation cost.
Dedicated Circuit
A separate electrical circuit with its own circuit breaker in the panel box, reserved exclusively for the aircon. Required for all split-type and high-HP units. Prevents overloading and tripping.
Line Set
The pair of insulated copper tubes (liquid line and suction line) connecting the indoor and outdoor units. Carries refrigerant in both directions. Must be properly insulated to prevent condensation.
Core Drilling
Creating a circular hole through concrete walls for routing copper piping between indoor and outdoor units. Requires a specialized drill with diamond-tipped core bits. Costs ₱800–₱1,500 per hole.
Bracket / Mounting Plate
Metal support structure for the indoor wall unit (mounting plate) or outdoor unit (L-bracket or floor stand). Must be securely anchored to withstand the unit's weight and vibration.
Commissioning
The systematic process of verifying that a newly installed HVAC system operates according to design specifications. Includes refrigerant charging, airflow balancing, controls testing, and documentation.
Ductwork Sizing
Engineering calculation determining the correct duct dimensions to deliver the required airflow to each zone without excessive static pressure loss or noise. Typically uses the equal friction method.
Regulations & Standards
ASHRAE
American Society of Heating, Refrigerating and Air-Conditioning Engineers — the primary international standard-setting body for HVAC. Philippine building specifications often reference ASHRAE 62.1 (ventilation), 90.1 (energy), and 55 (thermal comfort).
TESDA NC II (RAC Servicing)
Technical Education and Skills Development Authority National Certificate II for Room Air Conditioning Servicing — the official Philippine qualification for aircon technicians. Verified TESDA-certified technicians have passed standardized competency assessments.
DOE Energy Efficiency Label
The Philippine Department of Energy's mandatory energy label for air conditioners showing the EER rating and yearly energy cost. Units are rated 1-5 stars; 5-star units meet the highest efficiency standards.
PCAB (Philippine Contractors Accreditation Board)
Government agency under DPWH that licenses and regulates contractors in the Philippines. Commercial HVAC installation contracts above certain amounts require a PCAB-licensed mechanical contractor.
DENR Administrative Order on Refrigerants
Department of Environment and Natural Resources regulations governing the import, use, and disposal of refrigerants in the Philippines under the Montreal Protocol. Prohibits new installations using R22.
PEC (Philippine Electrical Code)
Standards governing electrical installations in the Philippines, including dedicated circuit requirements for air conditioning equipment. Compliance is mandatory for building permit issuance.
NBC (National Building Code of the Philippines)
Presidential Decree 1096 — governs construction standards including mechanical and ventilation requirements. Specifies minimum fresh air requirements and HVAC equipment clearances for commercial buildings.
Montreal Protocol
International treaty signed by the Philippines committing to phase out ozone-depleting substances. Drives the ongoing phase-out of R22 refrigerant and the transition to R32 and other low-GWP alternatives.
GWP (Global Warming Potential)
A measure of how much a refrigerant contributes to climate change over 100 years, relative to CO2 (GWP=1). R32 has GWP of 675; R410A has GWP of 2,088; R22 has GWP of 1,810.
Energy & Efficiency
IPLV (Integrated Part-Load Value)
Efficiency metric for chillers measuring performance across a range of part-load conditions (100%, 75%, 50%, 25%). More representative of real-world Philippine commercial building operation than full-load COP alone.
Demand Response
The ability of HVAC systems to reduce energy consumption during peak grid demand periods. Smart inverter systems and BMS-connected equipment can participate in utility demand response programs.
kWh per Ton
Energy consumption per unit of cooling capacity — a practical metric for comparing chiller efficiency. Lower is better. Efficient Philippine commercial chillers achieve 0.5-0.7 kWh/ton.
Economizer
A control strategy that uses cool outdoor air to supplement or replace mechanical cooling when outdoor conditions allow. Reduces compressor run time and energy costs. Most effective in Philippine highland locations.
Part-Load Efficiency
HVAC efficiency at less than full capacity — typically 50-75% load, which represents the most common operating condition in Philippine buildings. Inverter systems excel at part-load efficiency.
Setback Temperature
A higher cooling setpoint used when a space is unoccupied to reduce energy use. Philippine offices commonly set back from 24°C occupied to 28-30°C during nights and weekends.
Thermostat Deadband
The temperature range around the setpoint where the HVAC system does not activate. A wider deadband (e.g., ±1°C) reduces compressor cycling and improves efficiency at the cost of tighter temperature control.
Enthalpy Control
A strategy that considers both temperature and humidity to determine the most energy-efficient cooling approach. Particularly relevant in the Philippines where high humidity increases the energy needed for dehumidification.
Also explore the mraircon.ai Aircon Encyclopedia for in-depth guides:
Aircon Encyclopedia on mraircon.ai