BTU Calculator
Calculate heating and cooling BTU requirements
Length of the room
Width of the room
Standard: 8 ft
Affects BTU per sq ft
Afternoon sun increases cooling load
Cooling BTU
—
BTU/h
Heating BTU
—
BTU/h
AC Tonnage
—
tons
Heater Wattage
—
watts
How to Use This Calculator
Our BTU calculator helps you size heating and cooling equipment properly. Correct sizing is critical for comfort and efficiency.
- Measure room dimensions
- Assess insulation quality and sun exposure
- Enter specifications
- Use results to select properly sized HVAC equipment
AI Insights
Smart analysis for your project
Smart Estimates
Our AI cross-references material costs, regional pricing, and project complexity for more accurate estimates.
Waste Optimization
AI-calculated waste factors based on project type, not flat percentages. Saves 5-15% on material costs.
Best Practices
Recommendations derived from building codes, contractor data, and thousands of completed projects.
Calculation Formula
Base BTU = Area x 25 (cooling) or x 35 (heating)
Adjustments for ceiling height, insulation, sun exposure
1 ton AC = 12,000 BTU/h
Frequently Asked Questions
How many BTU per square foot?
Cooling: 20-25 BTU/sq ft. Heating: 30-40 BTU/sq ft. Kitchens and sunrooms need 10-20% more.
What does AC tonnage mean?
One ton = 12,000 BTU/h. A 2-ton unit provides 24,000 BTU/h. Most residential AC units range 1.5-5 tons.
What happens if my AC is oversized?
Oversized units short-cycle, reducing dehumidification, increasing energy bills, and shortening equipment life.