Tons of Refrigeration vs BTU/hr: Latent Heat Capacity & HVAC Sizing
One nominal ton of refrigeration is mathematically defined as the latent heat of fusion required to freeze one short ton (2,000 lbs) of water at 32°F into ice over a 24-hour period (2,000 lbs * 144 BTU/lb / 24 hrs = 12,000 BTU/hr). In modern residential and commercial HVAC design, tonnage defines cooling capacity.
Technical Comparison & Conversion Matrix
| Nominal Cooling Tons | BTU/hr Capacity | Airflow Requirement (@ 400 CFM/ton) | Typical Conditioned Home Size |
|---|---|---|---|
| 1.5 Tons | 18,000 BTU/hr | 600 CFM | 700 - 1,000 sq ft |
| 2.0 Tons | 24,000 BTU/hr | 800 CFM | 1,000 - 1,300 sq ft |
| 2.5 Tons | 30,000 BTU/hr | 1,000 CFM | 1,300 - 1,600 sq ft |
| 3.0 Tons | 36,000 BTU/hr | 1,200 CFM | 1,600 - 2,000 sq ft |
| 3.5 Tons | 42,000 BTU/hr | 1,400 CFM | 2,000 - 2,400 sq ft |
| 4.0 Tons | 48,000 BTU/hr | 1,600 CFM | 2,400 - 2,800 sq ft |
| 5.0 Tons | 60,000 BTU/hr | 2,000 CFM | 2,800 - 3,500 sq ft |
Live Calculator: Residential & Commercial Heat Load (Manual J) Tonnage Calculator
Compute conversion ratios and values instantly on the Cloudflare edge runtime.
Computed Output
Interactive Online Calculators
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Residential & Commercial Heat Load (Manual J) Tonnage Calculator
Estimate residential cooling and heating heat loss/gain in BTU/hr and required HVAC air conditioning tonnage.
BTU to CFM Airflow Calculator
Convert sensible heating and cooling BTU/hr to required CFM airflow and tonnage for HVAC design.
CFM to BTU/hr Capacity Calculator
Convert airflow CFM and temperature split to sensible thermal BTU/hr output for HVAC equipment.
Frequently Asked Questions
Why is oversizing AC tonnage harmful to indoor comfort and efficiency?
Oversized cooling equipment satisfies the thermostat too quickly ('short-cycling'), which prevents the evaporator coil from running long enough to condense humidity out of the air. This results in cold, clammy rooms, high indoor relative humidity (>60%), and premature compressor wear.
What is the relationship between cooling tons, BTU/hr, and electrical power consumption?
At SEER2 16, a 3-ton (36,000 BTU/hr) central air conditioner consumes approximately 2,250 watts (2.25 kW) of electric power during full compressor operation (36,000 / 16 = 2,250 W).