Engineering Tools

HVAC LoadCalculator

Calculate heating and cooling loads per ACCA Manual J. Size HVAC equipment properly for energy efficiency and comfort.

HVAC Load Calculation

HVAC Sizing

Cooling Load3.5tons
Heating Load45,000BTU/hr

Load Breakdown

Sensible Cooling36,000 BTU/hr
Latent Cooling6,000 BTU/hr
Infiltration8,000 BTU/hr
Internal Gains4,000 BTU/hr
Recommended Unit3.5 Ton AC / 60k BTU Furnace

Rule of Thumb

  • Mild: 500-600 sqft/ton
  • Hot: 400-500 sqft/ton
  • Cold: 30-40 BTU/sqft
  • Always do Manual J calc

Load Factors

  • Windows: Major heat gain/loss
  • Insulation: Critical factor
  • Occupants: 300-400 BTU/person
  • Appliances: Add 1-3k BTU

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