HVAC Duct Calculator

CFM Calculator for 150 Sq Ft Room

Find the exact CFM airflow needed for a 150 square foot room. Get recommended duct sizes, BTU load estimates, and HVAC sizing data for 150 sqft spaces.

Airflow Requirements for 150 Square Feet

Required CFM
150
Est. BTU Load
3,750
Cooling Tons
0.31
Duct Size
8"

A 150 square foot room requires approximately 150 CFM of airflow for proper heating and cooling. This is based on the industry standard rule of 1 CFM per square foot. The estimated cooling load is 3,750 BTU (0.31 tons), and the recommended round duct size is 8 inches at a quiet velocity of 700 FPM.

How We Calculated This

Step 1: CFM Requirement CFM = 150 sqft × 1 CFM/sqft = 150 CFM
Step 2: BTU Load Estimate BTU = 150 sqft × 25 BTU/sqft = 3,750 BTU

Using 25 BTU per square foot as a general residential estimate. Actual load depends on insulation, climate, and sun exposure.

Step 3: Duct Size Diameter = √(4 × 150 ÷ (π × 700)) × 12 ≈ 8 inches

Based on 700 FPM velocity for quiet residential operation.

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