Calculate sensible heat ratio (SHR), sensible and latent load breakdown, and equipment sizing implications.
⚡ Load Inputs
From BTU/hr Values
From Airflow + Conditions
Dry heat: conduction, solar, lights, people (sensible)
Moisture: people, OA humidity, infiltration
Typically 55–70 gr/lb at 75°F / 50% RH
Leaving cooling coil, typically 35–50 gr/lb
📊 Results
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Sensible Heat Ratio (SHR)
—
Total Load (BTU/hr)
—
Sensible (BTU/hr)
—
Latent (BTU/hr)
—
Total Cooling (Tons)
Sensible
Latent
■ SensibleLatent ■
⚠ High Latent Load (SHR < 0.75): Consider a dedicated dehumidification system, hot gas reheat, or desiccant wheel to handle excess moisture.
✔ Normal SHR: Standard DX or chilled water cooling coil can handle this load profile.
Equipment Note: Equipment SHR is typically 0.70–0.80. If your space SHR is lower than equipment SHR, the space will be over-cooled (too cold) before meeting humidity targets — consider supplemental dehumidification.
📚 Typical SHR by Space Type
Space Type
Typical SHR
Latent Load Source
Level
Office / Commercial
0.85–0.95
People, ventilation OA
Low Latent
Retail
0.80–0.90
People, OA, infiltration
Low Latent
Restaurant / Kitchen
0.65–0.75
Cooking, high OA, steam
High Latent
Gym / Fitness
0.65–0.75
Heavy occupancy sweat load
High Latent
Natatorium / Pool
0.30–0.55
Evaporation from water surface
High Latent
Hospital Patient Room
0.70–0.80
People, OA requirements
Med Latent
Warehouse
0.90–0.98
Minimal occupancy
Low Latent
Humid Climate (summer)
0.70–0.80
OA humidity, infiltration
High Latent
Inputs, results, and method — as an Excel workbook or plain CSV.
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📝 About This Calculator
This sensible vs latent split calculator finds the sensible heat ratio (SHR) and the breakdown of a cooling load into dry sensible heat and moisture-removal latent heat. Enter the loads directly in BTU/hr, or enter supply airflow with room and supply dry-bulb temperatures and humidity ratios and let the tool compute each component.
SHR is the single number that tells you whether a space is mostly a cooling problem or also a humidity problem. The tool plots the split, reports total tons, and flags low-SHR cases where supplemental dehumidification — reheat, a dedicated dehumidifier, or a desiccant wheel — is usually needed.
🔢 Formula & Method
Quantity
Equation
Sensible heat ratio
SHR = Sensible ÷ (Sensible + Latent)
Sensible load
Q‑sens = 1.08 × CFM × ΔT (°F)
Latent load
Q‑lat = 0.68 × CFM × ΔW (gr/lb)
Total cooling
Tons = (Sensible + Latent) ÷ 12,000
The airside constants follow ASHRAE Fundamentals: 1.08 for sensible heat (specific heat × density × 60) and 0.68 for latent heat when the humidity-ratio difference ΔW is in grains per pound of dry air. SHR is the sensible fraction of the total; equipment SHR is typically 0.70–0.80, so a lower space SHR signals a need for supplemental dehumidification.
❓ Frequently Asked Questions
What is sensible heat ratio (SHR)?
Sensible heat ratio is the sensible cooling load divided by the total cooling load, where total is sensible plus latent. An SHR of 0.80 means 80 percent of the load is dry sensible heat and 20 percent is moisture removal. It describes the balance between cooling the air down and drying it out, which drives how a cooling coil and any dehumidification are selected.
What does a low SHR mean for equipment selection?
A low SHR, below about 0.75, means a large share of the load is latent moisture. Standard cooling equipment has an SHR near 0.70 to 0.80, so when the space SHR is even lower, the coil tends to over-cool the air before it removes enough moisture. That points to supplemental dehumidification such as hot gas reheat, a dedicated dehumidifier, or a desiccant wheel.
How is the split found from airflow and conditions?
Sensible load is 1.08 times CFM times the dry-bulb temperature difference between room and supply air. Latent load is 0.68 times CFM times the humidity-ratio difference in grains per pound between room and supply air. The 1.08 and 0.68 factors are the standard sea-level airside constants from ASHRAE Fundamentals. Adding the two gives the total, and sensible over total is the SHR.
Which spaces typically have high latent loads?
Spaces with lots of moisture or high outdoor air have low SHRs and high latent fractions: restaurants and kitchens, gyms and fitness rooms, natatoriums and pools, and any space in a humid climate with significant ventilation. Offices, retail, and warehouses are mostly sensible with SHRs from about 0.85 to 0.98. The reference table on this page lists typical values by space type.
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Results are design estimates for preliminary sizing. Verify final designs against applicable codes and standards — engineering judgment and a licensed professional engineer’s review are required.