HVAC Load Calculator

Estimate heating and cooling requirements in seconds

Use this HVAC load calculator to estimate heating and cooling loads based on room size, insulation, windows, and climate.

HVAC Load Estimator

Input Method

Room Length (ft) Room Width (ft) Room Height (ft)

Number of Windows Insulation Quality (1=Poor, 5=Excellent) Climate Zone

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How HVAC Load is Calculated

This calculator uses square footage or room volume, adjusts for insulation quality, adds heat gain from windows, and applies a climate factor to estimate BTU requirements.

Example Calculation

Area: 300 sq ft
Volume: 2,400 cubic ft
Cooling Load: ~6,000 BTU/hr
Heating Load: ~6,600 BTU/hr

HVAC Facts

1 ton = 12,000 BTU/hr
20 BTU per sq ft is a common baseline
Windows significantly increase cooling load

Tips

Always add 10–15% safety margin
Better insulation reduces system size
Avoid oversizing HVAC systems

Frequently Asked Questions

What is HVAC load?
The heating/cooling required to maintain comfort.

What affects load?
Size, insulation, windows, and climate.

Should I oversize?
Slightly, but not excessively.