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Module 6

HVAC Systems

Overview

HVAC (Heating, Ventilation, and Air Conditioning) systems control indoor comfort and represent significant equipment investments. In Texas, air conditioning is essential, and HVAC systems face demanding conditions. Understanding system types, efficiency ratings, and common issues helps agents advise clients on equipment condition, remaining life, and potential replacement costs.

Learning Objectives

After completing this module, you should be able to:

  • 1Understand air conditioning and heating system types and components
  • 2Interpret efficiency ratings (SEER for cooling, AFUE for heating)
  • 3Identify critical HVAC components including ductwork, thermostats, and filtration
  • 4Recognize common HVAC issues and red flags during showings

Key Concepts

The following key concepts are essential to understanding this module:

Air Conditioning Systems
Central air conditioning has two main components: the outdoor condenser (containing compressor and condensing coil) and the indoor unit (evaporator coil and air handler). In Texas, systems typically last 10-15 years due to extreme heat. SEER (Seasonal Energy Efficiency Ratio) measures efficiency—2023+ requires 15 SEER2 minimum in southern states. R-22 refrigerant (pre-2010 systems) is phased out and expensive; R-410A is the current standard.
Heating Systems
Gas furnaces burn natural gas and distribute heated air through ductwork, rated by AFUE (80% standard, 90-98% high efficiency) with 15-25 year lifespan. Heat pumps provide both heating and cooling by reversing the refrigeration cycle—efficient in mild climates but need supplemental heat below 30-35°F. Electric resistance heating is 100% efficient but expensive to operate. Safety concerns include carbon monoxide from cracked heat exchangers, gas leaks, and improper venting.
Critical HVAC Components
Ductwork distributes conditioned air and should be sealed, insulated, and properly sized—leaks can waste 20-30% of conditioned air. Ducts in unconditioned attics face extreme temperatures (150°F+ in summer). Thermostats range from basic to smart models that can reduce energy costs 10-15%. Air filters protect equipment and improve air quality—dirty filters restrict airflow and can damage equipment.
Common HVAC Issues and Red Flags
Warning signs include unusual sounds (grinding, squealing, banging), inconsistent temperatures, weak airflow, strange odors, frequent cycling, moisture around units, and high utility bills. For condensers: check age, physical condition, level installation, 2-foot clearance, vegetation blocking airflow, and ice on refrigerant lines. For air handlers: check for leaks, rust, proper installation, and condensate drain condition.

Important Terms

Make sure you understand these terms before taking the quiz:

SEER (Seasonal Energy Efficiency Ratio)

Measure of air conditioning cooling efficiency. Higher SEER means more efficient and lower operating costs. 2023+ requires 15 SEER2 minimum in southern states.

R-22 Refrigerant (Freon)

Refrigerant used in systems before 2010, now phased out due to ozone depletion. Remaining supply is expensive ($100+ per pound), making systems requiring R-22 economically impractical to maintain.

Heat Pump

System providing both heating and cooling by reversing the refrigeration cycle. Efficient in mild climates like Texas, but needs supplemental heat when outdoor temperatures drop below 30-35°F.

AFUE (Annual Fuel Utilization Efficiency)

Rating for gas furnace efficiency. Standard efficiency is 80% AFUE; high-efficiency condensing furnaces achieve 90-98% AFUE by capturing more heat from combustion.

Condensate Drain

System that removes humidity extracted by air conditioning. Should include primary drain, secondary/emergency drain or safety switch, and proper slope. Clogged drains cause water damage—a common insurance claim.

TPR Valve (on Water Heater)

Temperature and Pressure Relief valve—critical safety device that releases pressure if temperature or pressure becomes dangerous. Discharge pipe must route within 6 inches of floor or exterior.

Ductwork

System of tubes that distributes conditioned air throughout the home. Should be sealed, insulated in unconditioned spaces, and properly sized. Leaky ductwork can waste 20-30% of conditioned air.

Summary

Texas heat shortens AC lifespan—expect 10-15 years from central air conditioning, not the 15-20 years often cited. R-22 refrigerant means replacement is near, as systems using R-22 (pre-2010) are approaching mandatory replacement with expensive and limited refrigerant supply. SEER ratings affect operating costs, with high-efficiency systems potentially saving $500+ annually. Furnace safety matters—gas furnaces require proper venting and functional carbon monoxide detectors. Duct leakage wastes energy, with leaky ductwork losing 20-30% of conditioned air. Get HVAC inspection for older systems—equipment over 10 years old warrants inspection by an HVAC professional.

Additional Resources

For further study, consider exploring these resources:

  • Texas Real Estate Commission (TREC) — State regulatory agency providing guidance on disclosure requirements and inspector standards for HVAC issues.
  • Air Conditioning Contractors of America (ACCA) — Industry organization with resources on HVAC system installation, maintenance, and finding qualified contractors.
  • American Society of Home Inspectors (ASHI) — Professional organization offering standards and resources for home inspection, including HVAC systems.