Resources
San Diego HVAC glossary
The HVAC words that show up on quotes, permits, and rebate forms, in plain English. No jargon for jargon's sake, just what each term means for a San Diego home.
Equipment and terms
- SEER2
- Seasonal Energy Efficiency Ratio 2, the 2023+ efficiency metric for AC and heat pumps. California minimum is 15 SEER2 split systems; federal Inflation Reduction Act rebates require 16+ SEER2.
- Manual J
- ACCA's residential heating and cooling load-calculation standard. Running Manual J is how a contractor determines the correct equipment size for your specific home, oversizing wastes money, undersizing fails to cool in peak heat.
- Heat pump
- System that both heats and cools using a refrigerant cycle, replaces a separate AC and gas furnace. Often the best fit for San Diego's mild climate. Rebate availability changes year to year, so confirm current SDG&E and state programs before you count on a number.
- Ductwork R-value
- Insulation rating of supply/return duct. California Title 24 requires R-8 minimum in unconditioned attic space, older homes often have R-4.2 that fails current code.
- MERV rating
- Minimum Efficiency Reporting Value, filter efficiency rating from 1-16. MERV 13 is the sweet spot for residential IAQ without over-restricting airflow.
- Condensate line
- PVC drain that carries evaporator-coil condensate to the exterior. Clogs cause backup, ceiling damage, and system shutoff, annual flush is basic maintenance.
- Short cycling
- When a system runs for under 10 minutes then shuts off repeatedly. Usually indicates oversized equipment, low refrigerant, or failing capacitor. Accelerates compressor failure.
Materials and refrigerants
- R-454B
- The low-GWP refrigerant replacing R-410A in 2025+ residential HVAC equipment per EPA rules. Mildly flammable (A2L class), technicians need updated leak-detection equipment.
San Diego specifics
- Marine layer
- Coastal fog + humidity affecting the western third of SD County from May-September. Keeps outdoor temps mild but raises indoor humidity loads. Most coastal HVAC systems benefit from dehumidification integration.
- Santa Ana winds
- Dry, hot easterly winds in fall/winter that push inland temps past 100°F and drop humidity below 10%. Forces AC systems to run hard during what's supposed to be shoulder season.
- SDG&E EV-TOU-5
- San Diego Gas & Electric's time-of-use rate plan for EV owners, heavily discounted 12am-6am super-off-peak pricing makes nighttime pool, AC pre-cooling, and EV charging cost-effective.
Licensing
- C-20 HVAC
- California CSLB Class C-20, Warm-Air Heating, Ventilating & Air-Conditioning. Required for system installation, refrigerant handling, ductwork modification, and most permitted HVAC work.
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