HVAC Study Guide 2026
Everything you need to pass the HVAC exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 HVAC Exam Format at a Glance
📚 HVAC Topics to Study (51)
✍️ Sample HVAC Questions & Answers
1. What is the significance of 'HSPF2' rating for a mini-split heat pump?
HSPF2 (Heating Seasonal Performance Factor 2) is the heating efficiency rating for heat pumps, measured over a full heating season. Higher values indicate better efficiency. Mini-splits typically achieve HSPF2 of 8-14+, significantly better than electric resistance heating (HSPF2 equivalent of 3.41).
2. What is the typical fin spacing (fins per inch) for a residential evaporator coil?
Residential evaporator coils typically have 8-14 fins per inch, balancing heat transfer efficiency with acceptable airflow resistance and ease of cleaning.
3. What is the saturation temperature of a refrigerant?
Saturation temperature is the temperature at which a refrigerant changes between liquid and vapor states at a specific pressure.
4. What is 'load calculation' software (like Manual J or HAP) used for?
Load calculation software (Manual J for residential, ASHRAE Handbook or HAP/Trace for commercial) calculates the heating and cooling loads for a specific building based on construction, climate, occupancy, and internal gains. Proper load calculations prevent over- or under-sizing equipment.
5. What is MERV rating and why are commercial HVAC filters rated higher than typical residential filters?
MERV (Minimum Efficiency Reporting Value, ASHRAE 52.2) rates particle removal efficiency. Commercial buildings require higher MERV filters (MERV 8-14) due to more occupants, regulatory requirements (ASHRAE 62.1), and higher expectations for air quality, despite the increased pressure drop.
6. What is the purpose of a refrigerant recovery machine's oil separator?
The oil separator in a recovery machine removes compressor oil that may have mixed with the refrigerant during the recovery process, keeping the recovered refrigerant cleaner.