Cooling Coil Selection Calculator

Evaluate coil duty, airflow, and sensible-latent performance quickly. Review face velocity, rows, and leaving air. Make better equipment choices for efficient, reliable climate control.

Calculator Inputs

Airflow (CFM)

Entering Dry-Bulb (°F)

Entering Wet-Bulb (°F)

Target Leaving Dry-Bulb (°F)

Design SHR

Face Area (sq ft)

Maximum Face Velocity (fpm)

Available Coil Rows

Fouling Factor

Safety Factor

Coil Approach (°F)

Bypass Factor

Formula Used

This selector uses common HVAC quick-sizing relationships and a simplified psychrometric method to estimate airside cooling performance.

Total capacity: Q_total = 4.5 × CFM × (h_in − h_out)
Sensible capacity: Q_sensible = 1.08 × CFM × (T_in − T_out)
Latent capacity: Q_latent = Q_total − Q_sensible
Estimated SHR: SHR = Q_sensible ÷ Q_total
Face velocity: Velocity = CFM ÷ Face Area
Selected capacity: Larger of calculated or design load, adjusted by safety and fouling factors

This method is excellent for preliminary selection, budgeting, and comparison. Final coil choices should still be verified with manufacturer performance software and exact fluid conditions.

How to Use This Calculator

Enter the design airflow in CFM.
Provide entering dry-bulb and wet-bulb air conditions.
Enter the desired leaving dry-bulb temperature.
Set the target sensible heat ratio for the application.
Input face area, allowable face velocity, and available coil rows.
Adjust fouling, safety factor, coil approach, and bypass factor if needed.
Press the calculate button to see capacity, moisture, velocity, and selection status.
Use the CSV or PDF buttons to export the current result set.

Example Data Table

Scenario	Airflow (CFM)	Entering DB/WB (°F)	Leaving DB (°F)	Face Area (sq ft)	Estimated Total Capacity (Btu/h)	Status
Office AHU	8000	80 / 67	55	18	182,000	Recommended
Retail Fresh Air	12000	85 / 70	54	24	287,000	Review Required
Server Support Zone	5500	78 / 64	56	14	109,000	Recommended

FAQs

1. What does this calculator help me choose?

It estimates whether an airside cooling coil can handle the airflow, sensible load, latent load, and face velocity limits you enter for preliminary HVAC selection.

2. Is this suitable for final procurement?

No. It is best for screening and comparison. Final coil selection should always be checked with manufacturer software, exact geometry, fluid data, and scheduled project conditions.

3. Why are wet-bulb and humidity included?

Cooling coils often remove moisture as well as sensible heat. Wet-bulb information helps estimate humidity ratio, enthalpy change, latent capacity, and leaving air condition.

4. What is a good face velocity target?

Many comfort applications aim near 400 to 500 fpm. Higher values can increase pressure drop, carryover risk, and selection difficulty, depending on coil depth and fin spacing.

5. What does bypass factor mean here?

It represents the fraction of air that behaves as if it bypasses full coil contact. Lower bypass factors usually indicate deeper or more effective coils.

6. Why is the recommended row count changing?

Higher tonnage, tighter moisture targets, or higher face velocity usually need deeper coils. More rows improve contact, heat transfer, and dehumidification capability.

7. What is the safety factor doing?

It increases the selected capacity to account for design uncertainty, margin preference, or conservative selection practice before final manufacturer confirmation.

8. Can I use metric values with this page?

This version is arranged around inch-pound HVAC relationships. Convert metric inputs before entry, or adapt the formulas and labels for a metric project version.