Convert EER to kW/Ton or kW/Ton to EER, and estimate total input power from optional cooling capacity in BTU/hr or kW with selectable units.
EER to kW Ton Formula
The following formula is used to convert EER to kW per ton of cooling capacity:
Variables:
- kW/Ton is the power usage (input power) in kilowatts for each ton of cooling capacity.
- EER is the Energy Efficiency Ratio, which is the ratio of the cooling capacity (in BTU/hr) to the power input (in watts).
- Cooling Capacity is the amount of heat removed by the air conditioning system (in BTU/hr). Cooling capacity is not needed to convert EER to kW/Ton, but it can be used to estimate total input power.
To convert EER to kW per ton, divide 12 by the EER (the 12 comes from 12,000 BTU/hr per ton divided by 1,000 W per kW). If you also know the system cooling capacity, you can estimate total input power as: kW = (Cooling Capacity ÷ 12,000) × (kW/Ton) = Cooling Capacity ÷ (EER × 1,000).
| EER (BTU/(hr·W)) | kW per Ton (kW/Ton) |
|---|---|
| 6 | 2.000 |
| 7 | 1.714 |
| 8 | 1.500 |
| 9 | 1.333 |
| 10 | 1.200 |
| 11 | 1.091 |
| 12 | 1.000 |
| 13 | 0.923 |
| 14 | 0.857 |
| 15 | 0.800 |
| 16 | 0.750 |
| 17 | 0.706 |
| 18 | 0.667 |
| 20 | 0.600 |
| 22 | 0.545 |
| 24 | 0.500 |
| 25 | 0.480 |
| 28 | 0.429 |
| 30 | 0.400 |
| 35 | 0.343 |
| Assumes 1 refrigeration ton = 12,000 BTU/hr. Formula: kW/Ton = 12 ÷ EER (BTU/(hr·W)). | |
What is EER?
Energy Efficiency Ratio (EER) is a measure of how efficiently a cooling system operates when the outdoor temperature is at a specific level (typically 95°F). A higher EER rating indicates a more efficient air conditioning system. EER is calculated by dividing the cooling capacity in British Thermal Units (BTU) per hour by the power input in watts.
How to Calculate kW/Ton from EER?
The following steps outline how to calculate kW per ton from EER.
- First, determine the Energy Efficiency Ratio (EER) of the air conditioning system.
- Calculate kW per ton using: kW/Ton = 12 ÷ EER.
- (Optional) If you know the system cooling capacity, convert it to tons: Tons = Cooling Capacity (BTU/hr) ÷ 12,000.
- (Optional) Estimate total input power: kW = (kW/Ton) × Tons = Cooling Capacity ÷ (EER × 1,000).
Example Problem :
Use the following variables as an example problem to test your knowledge.
Energy Efficiency Ratio (EER) = 10
Cooling Capacity = 24000 BTU/hr
kW/Ton = 12 ÷ 10 = 1.2 kW/Ton. Since 24,000 BTU/hr = 2 tons, the estimated total input power is 1.2 × 2 = 2.4 kW.
