CALTRX

BTU Calculator

Enter room size to estimate heating/cooling BTU needs.

BTU = sqft * 20 * adjustments
sqft= Room area
20= Base BTU/sqft

Tips & Notes

  • ✓1 ton = 12000 BTU.
  • ✓Poor insulation adds 30%.
  • ✓Add 600 BTU per extra person.
  • ✓Round up to next equipment size.

Common Mistakes

  • ✗Ignoring ceiling height.
  • ✗Not accounting for insulation.
  • ✗Forgetting occupant heat.
  • ✗Wrong room measurements.

BTU Calculator Overview

What This Calculator Does

Estimates BTUs for HVAC from square footage, ceiling height, insulation, and occupancy. Base: sqft*20, adjusted for conditions.

Sizing

Undersized units never reach comfort. Oversized units short-cycle, wasting energy. Proper sizing is critical.

Factors

Poor insulation +30%. Good insulation -20%. Each occupant beyond 2 adds 600 BTU. Kitchens add ~4000 BTU.

Conversions

1 ton AC = 12,000 BTU/hr. 1 BTU = 0.293 watts.

Frequently Asked Questions

Energy to raise 1 lb water by 1F.

Modern=good, 1980-2010=average, older=poor.

The BTU Calculator uses standard validated formulas and provides results accurate to multiple decimal places. Review the step-by-step explanation to verify each calculation.

Yes, the BTU Calculator is fully responsive and works on all devices including smartphones, tablets, and desktop computers.