Glossary
Use this glossary when you are comparing an estimate, reading a Learning Center guide, or trying to understand what a technician is telling you. The definitions are educational, Houston-specific, and written without sales pressure.
How to use this page
Each entry starts with the short definition, then explains why it matters in a Greater Houston home. Links point to related Avatex services or Learning Center guides.
Efficiency & ratings
These are the numbers homeowners see on estimates, AHRI certificates, energy labels, and tax-credit conversations.
SEER2 is the current cooling-efficiency rating for residential AC and heat pump systems, updated in 2023 to better reflect real-world static pressure and field conditions.
A higher SEER2 rating can reduce cooling energy use, but the right value depends on equipment match, ductwork, humidity control, and how long you expect to stay in the home.
AFUE stands for Annual Fuel Utilization Efficiency, a heating-efficiency percentage that estimates how much fuel a furnace turns into usable heat.
A 95% AFUE furnace wastes less fuel than an 80% AFUE furnace, but Houston homeowners should compare furnace efficiency against heat pump options and local usage patterns.
HSPF and HSPF2 measure heat pump heating efficiency across a season; HSPF2 is the newer test standard aligned with updated federal equipment ratings.
Houston winters are mild enough that a well-sized heat pump can be efficient for many homes, but the electrical panel, ductwork, and comfort goals still matter.
BTU means British Thermal Unit, a standard measure of heat energy used to describe how much heating or cooling capacity equipment can move.
Bigger is not automatically better. Too much BTU capacity can short-cycle, remove less humidity, and leave a Houston home feeling clammy.
Manual J is the ACCA residential load-calculation method contractors use to estimate how much heating and cooling a specific home needs.
It accounts for square footage, insulation, windows, orientation, air leakage, and local climate. It is the difference between measuring the house and guessing.
An AHRI certificate documents a tested equipment match, usually pairing the outdoor unit, indoor coil, furnace or air handler, and efficiency ratings.
For a replacement quote, the AHRI certificate helps verify the quoted system's SEER2, EER2, and heating ratings instead of relying only on model names.
HVAC basics
These are the parts and system types that usually appear in AC repair, replacement, heat pump, and ductless conversations.
A heat pump is a reversible cooling system that can move heat out of the home in summer and move heat into the home in winter.
Because one system can cool and heat, heat pumps are often a practical fit for Houston, especially when the home has the electrical capacity and ductwork to support it.
A ductless mini-split is a zoned heat pump system that conditions a room or area without connecting to a central duct system.
Mini-splits are useful for garages, additions, converted rooms, and problem zones where extending ductwork is costly or inefficient.
An air handler is the indoor unit that houses the blower and often the evaporator coil, moving conditioned air through the home.
If airflow is weak, noisy, or uneven, the air handler, blower wheel, filter, duct pressure, or coil condition may be part of the diagnosis.
The condenser is the outdoor unit that rejects heat outside during cooling mode and contains major components such as the compressor, fan, coil, and controls.
A dirty condenser coil, failing fan motor, electrical fault, or refrigerant issue can all reduce cooling capacity in Houston heat.
The compressor is the pump inside the outdoor unit that circulates refrigerant through the system and raises refrigerant pressure.
Compressor failure can be one of the most expensive AC repairs. Age, warranty status, refrigerant type, and system condition usually decide repair versus replacement.
A coil is a heat-exchange surface: the indoor evaporator coil absorbs heat and moisture, while the outdoor condenser coil releases heat.
Dirty, frozen, corroded, or leaking coils can hurt comfort, airflow, humidity removal, and efficiency.
A capacitor is an electrical component that helps motors start and run, commonly used with AC compressors and fan motors.
In hot weather, weak capacitors are a common failure point. Replacing one may solve a no-cool issue, but the technician should still check why the motor struggled.
A thermostat is the control that tells the HVAC system when to heat, cool, or run the fan; smart thermostats add scheduling and remote access.
Thermostat settings, placement, wiring, and compatibility can affect comfort and system operation, especially with heat pumps and staged equipment.
Refrigerant is the fluid that absorbs and releases heat as it changes pressure and state inside an air conditioner or heat pump.
A system should not need refrigerant added unless there is a leak or service issue. Low refrigerant is a symptom, not a normal maintenance item.
R-410A is a common refrigerant in modern residential AC systems, while R-454B is one lower-GWP A2L refrigerant many manufacturers use for newer equipment.
The refrigerant transition affects equipment availability, service parts, code requirements, and how replacement estimates should be compared.
Electrical & permits
Avatex is both a Texas HVAC contractor and electrical contractor, which matters when comfort work touches panels, breakers, circuits, and permits.
TACLA is the Texas HVAC contractor license prefix; TECL is the Texas electrical contractor license prefix.
Avatex lists TACLA #89729C and TECL #34162, plus Master Electrician #535138. Those credentials matter when HVAC work overlaps electrical scope.
A permit is local authorization from the authority having jurisdiction before certain HVAC, electrical, or insulation-related work is installed or inspected.
Permit requirements vary across City of Houston, Harris County, Montgomery County, Fort Bend County, Brazoria County, and other local AHJs.
AHJ means authority having jurisdiction, the local office or agency responsible for enforcing permits, inspections, and code requirements.
Two homes in the Greater Houston area can have different permit offices, timelines, and inspection steps depending on city and county boundaries.
The electrical panel is the home's central distribution point, where incoming power is divided into protected circuits.
A heat pump retrofit, major HVAC replacement, or added circuit may require checking panel capacity, breaker space, grounding, and code condition.
A circuit breaker is a protective switch designed to interrupt power when a circuit draws unsafe current.
Repeated tripping can point to overload, equipment failure, wiring problems, or a breaker issue. It should be diagnosed instead of ignored.
A dedicated circuit serves one appliance or piece of equipment rather than sharing power with general outlets or other loads.
Some HVAC, mini-split, IAQ, and electrical upgrades need a dedicated circuit sized for the equipment and installed to code.
Insulation & IAQ
Comfort is not only equipment. Air sealing, insulation, filtration, humidity, and airflow decide how the system performs in a Houston home.
Attic insulation slows heat transfer between the attic and living space, helping reduce heat gain in summer and heat loss in winter.
Under-insulated attics make AC systems run longer in Houston. Improving attic insulation can support comfort before or alongside equipment upgrades.
Blown-in insulation is loose-fill material installed with a blower to build even coverage over attic floors and hard-to-reach spaces.
It can be a practical way to raise attic R-value without removing large areas of existing insulation, when the existing material is dry and safe to cover.
R-value measures how well insulation resists heat flow; higher R-value means greater resistance when installed correctly.
R-value only performs as expected when insulation is properly installed, evenly distributed, and paired with air sealing and ventilation considerations.
Air sealing closes unwanted gaps, cracks, and penetrations where attic air, outdoor air, or crawlspace air can leak into conditioned space.
Air leaks can carry heat, humidity, dust, and odors. In Houston, uncontrolled air leakage can make humidity problems worse.
HEPA filtration captures at least 99.97% of particles at 0.3 microns in laboratory conditions when the filter and system are correctly designed.
True HEPA filtration is powerful, but not every residential HVAC system can accept a restrictive filter without airflow consequences.
MERV is a filter-efficiency rating that indicates how well a filter captures particles of different sizes.
Higher MERV can improve filtration, but too much restriction can reduce airflow. The right filter balances air quality and system design.
Dehumidification is moisture removal from indoor air, either through the AC system's cooling process or a dedicated dehumidifier.
Houston comfort depends heavily on moisture removal. A system can reach the thermostat setpoint and still feel sticky if humidity remains high.
Need a plain answer?
Avatex can review HVAC, electrical, and insulation recommendations and explain what is reasonable, what is missing, and what should be measured before work starts.
Last reviewed: June 24, 2026