Advanced Rheem Unit Tonnage Form
Direct values override model lookup. Leave direct fields blank when you want the calculator to read the Rheem capacity code.
Formula Used
Tons: Tons = BTU per hour ÷ 12,000
BTU per hour: BTU/h = Tons × 12,000
Cooling kW: Cooling kW = BTU/h × 0.00029307107
Thermal watts: Watts = Cooling kW × 1,000
Input watts: Input W = BTU/h ÷ EER
Single phase amps: Amps = Input W ÷ (Voltage × Power Factor)
Three phase amps: Amps = Input W ÷ (√3 × Voltage × Power Factor)
Design estimate: Design Amps = Total Amps × Safety Factor
How to Use This Calculator
- Enter the Rheem model number from the outdoor unit label.
- Select a manual capacity code if the model number is unclear.
- Use direct tons, BTU, kW, or watts when verified data is available.
- Enter voltage, phase, power factor, and efficiency assumptions.
- Add quantity, use hours, energy rate, and area details.
- Press the calculate button and review the result above the form.
- Use CSV for spreadsheets or PDF for field records.
Example Data Table
| Example Model Pattern | Capacity Code | Nominal Tons | BTU Per Hour | Cooling kW |
|---|---|---|---|---|
| RA1418AJ1NA | 18 | 1.5 | 18,000 | 5.28 |
| RA1424AJ1NA | 24 | 2.0 | 24,000 | 7.03 |
| RA1430AJ1NA | 30 | 2.5 | 30,000 | 8.79 |
| RA1436AJ1NA | 36 | 3.0 | 36,000 | 10.55 |
| RA1442AJ1NA | 42 | 3.5 | 42,000 | 12.31 |
| RA1448AJ1NA | 48 | 4.0 | 48,000 | 14.07 |
| RA1460AJ1NA | 60 | 5.0 | 60,000 | 17.58 |
Rheem Unit Tonnage Planning
A Rheem outdoor unit is usually selected by nominal cooling capacity. The calculator helps you read that capacity from a model number, a capacity code, or a direct BTU value. It then converts the value into tons, cooling kilowatts, thermal watts, input watts, and estimated current. This gives a clearer electrical view before a panel, feeder, or service discussion begins.
Why Tonnage Matters
One refrigeration ton equals 12,000 BTU per hour. A two ton unit is close to 24,000 BTU per hour. A three ton unit is close to 36,000 BTU per hour. Many Rheem model numbers include capacity codes such as 24, 30, 36, 42, 48, or 60. The code gives a fast field estimate, but the nameplate and submittal should always be checked.
Electrical Use
Cooling capacity is not the same as electrical input. The unit moves heat, so input power depends on efficiency. This tool estimates input watts by dividing BTU per hour by EER. It then estimates amperage from voltage, phase, and power factor. The result is useful for planning, but it is not a replacement for MCA, MOCP, breaker, conductor, or disconnect data printed on the equipment label.
Model Number Checks
Enter the full model number when available. The calculator searches for common Rheem capacity codes. You can also choose a code manually. Direct tons, BTU per hour, kW, or thermal watts can override the model lookup when exact design data is known.
Practical Use
Use the area field to compare installed capacity against square footage. High BTU per square foot may show oversizing. Low values may show a comfort risk. Actual sizing still needs Manual J load work, insulation review, duct condition, climate data, and latent load checks.
Reporting
After calculation, export the result as CSV for spreadsheets. Use the PDF button for field notes or customer records. The chart gives a quick visual summary of tonnage, cooling kW, input kW, and estimated amps. Keep every exported report with the date, assumptions, and verified nameplate values.
For best accuracy, compare the output with manufacturer literature, field measurements, and the exact equipment nameplate before ordering electrical materials onsite.
FAQs
1. How do I find Rheem unit tonnage?
Look for the capacity code in the model number. Common codes include 24, 30, 36, 42, 48, and 60. Divide the matching BTU value by 12,000 to estimate tons.
2. What does code 36 mean on a Rheem unit?
Code 36 usually points to about 36,000 BTU per hour. Since 12,000 BTU per hour equals one ton, this is commonly treated as a three ton unit.
3. Can this replace the equipment nameplate?
No. This calculator is for planning and quick estimates. Always use the actual nameplate for MCA, MOCP, voltage, phase, breaker, wire, and disconnect decisions.
4. Why does the calculator ask for EER?
EER helps estimate electrical input watts from cooling capacity. Higher EER usually means lower input watts for the same BTU rating.
5. Is cooling kW the same as input kW?
No. Cooling kW describes heat-moving capacity. Input kW describes estimated electrical power. HVAC equipment moves heat, so these numbers are different.
6. Why is there a breaker estimate?
The breaker estimate is only a rough planning number. HVAC breakers must follow the unit label, local code, conductor limits, and manufacturer instructions.
7. Can I use this for heat pumps?
Yes, you can estimate nominal cooling tonnage for heat pumps. Heating capacity may differ, so check the heating performance tables for cold weather design.
8. What if the model code is not detected?
Choose a capacity code manually or enter known tons, BTU, kW, or watts. Some model numbers use formats that need direct nameplate confirmation.