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Industry Load Method

Size Your HVAC System Right

Enter your space details and get an accurate BTU load and tonnage recommendation — no HVAC license required.

8Climate Zones
±10%Accuracy vs. Full Audit
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Good fit for this tool
  • Preliminary system sizing & budgeting
  • Comparing equipment options by tonnage
  • Checking a contractor’s recommendation
  • Residential new builds & replacements
  • Room-by-room load breakdown
Get a licensed engineer for
  • Permit applications & code compliance
  • Commercial or multi-unit buildings
  • Unusual construction (earthships, passive)
  • Geothermal or radiant system design
  • Any project requiring a stamped report
9 ft
Quick Start:
Results
Enter your space details above to see your load estimate

Educational estimate only. Results are estimates based on user inputs and simplified assumptions — not a certified engineering analysis. Local building codes and manufacturer specifications govern final equipment selection. No professional-client relationship is created by using this tool. For permit applications, commercial projects, or complex structures, consult a licensed HVAC engineer.

How HVAC Sizing Works

What Is a BTU?

A BTU (British Thermal Unit) is the energy needed to raise 1 lb of water by 1°F. HVAC systems are rated in BTU/hr — the higher your load, the larger your system needs to be.

Tons vs. BTU

One "ton" of cooling equals 12,000 BTU/hr. It comes from the heat absorbed by melting 1 ton of ice per day. Residential systems typically range from 1 to 5 tons.

Why Not Bigger?

An oversized system short-cycles — it cools too fast, shuts off, and never runs long enough to dehumidify properly. This leads to a clammy, uncomfortable home and higher wear on the equipment.

Learn How HVAC Load Calculations Work →