HVAC BTU Sizing Calculator
Estimate the required heating and air conditioning capacity (in BTUs and AC Tons) for your home based on regional climate and insulation.
Estimated HVAC Heating/Cooling Load
How are HVAC sizes calculated?
Air conditioners and furnace heat loads are measured in **BTUs (British Thermal Units)**. Selecting an HVAC unit that is too small means it will run continuously without reaching your set temperature. An oversized unit will "short cycle," shutting off before dehumidifying the air, leading to mold and high electric bills.
BTUs vs. AC Tons
Residential cooling equipment is commonly rated in **Tons**. One "Ton" of cooling is equal to **12,000 BTUs per hour** (the amount of heat energy required to melt 1 ton of ice over 24 hours):
- 1.5 Tons: 18,000 BTUs (covers roughly 600 - 900 sq ft)
- 2.0 Tons: 24,000 BTUs (covers roughly 900 - 1,200 sq ft)
- 2.5 Tons: 30,000 BTUs (covers roughly 1,200 - 1,500 sq ft)
- 3.0 Tons: 36,000 BTUs (covers roughly 1,500 - 1,800 sq ft)
- 3.5 Tons: 42,000 BTUs (covers roughly 1,800 - 2,100 sq ft)
- 4.0 Tons: 48,000 BTUs (covers roughly 2,100 - 2,400 sq ft)
- 5.0 Tons: 60,000 BTUs (covers 2,500+ sq ft)
Climate Zone Variables
Sizing requirements change by location. Southern US states (Zone 1 and 2) require high cooling capacities (30-35 BTUs/sqft), while Northern Plains states (Zone 5) require higher heating capacities (50 BTUs/sqft) to counter freezing winter winds. Our calculator incorporates these climate zones to customize the load calculation.