Sensible Heat Ratio (SHR) is the proportion of cooling capacity dedicated to reducing air temperature divided by total cooling capacity, expressed as a decimal between 0 and 1.0. This metric indicates how much of a system’s cooling power removes heat that raises air temperature versus heat that increases moisture content. SHR values directly impact humidity control and occupant comfort in conditioned spaces.
Technical Significance
A system with SHR 0.75 removes 75% of heat through temperature reduction and 25% through moisture removal. Standard residential systems typically operate at SHR between 0.70 and 0.85, with 0.75 considered ideal for most climates. Lower SHR values indicate greater dehumidification capability, beneficial in humid climates like Florida or Louisiana where outdoor air contains substantial moisture.
Comfort and Design Implications
Oversized cooling systems reduce SHR because short cycling prevents adequate dehumidification time. Contractors must select appropriately sized equipment and sometimes employ supplemental dehumidification in humid climates. Understanding SHR helps explain why properly sized systems maintain better humidity levels than oversized units, improving occupant comfort and indoor air quality.