| Nameplate or Brake Horsepower | Standard Fan Motor Efficiency | NEMA* High Efficiency | Premium Efficiency | 
| 1/20 | 40% | ... | ... | 
| 1/12 | 49% | ... | ... | 
| 1/8 | 55% | ... | ... | 
| 1/6 | 60% | ... | ... | 
| 1/4 | 64% | ... | ... | 
| 1/3 | 66% | ... | ... | 
| 1/2 | 70% | 76.0% | 80.0% | 
| 3/4 | 72% | 77.0% | 84.0% | 
| NOTE: For default drive efficiencies, see Nonresidential ACM Reference Manual | |||
| *NEMA - Proposed standard using test procedures. | |||
| Minimum NEMA efficiency as specified by test IEEE 112b Rating Method. | |||
| Motor Horsepower | Open Motors | Enclosed Motors | ||||||
| 2 pole 3600 rpm | 4 pole 1800 rpm | 6 pole 1200 rpm | 8 pole 900 rpm | 2 pole 3600 rpm | 4 pole 1800 rpm | 6 pole 1200 rpm | 8 pole 900 rpm | |
| 1 | 77.0 | 85.5 | 82.5 | 74.0 | 77.0 | 85.5 | 82.5 | 74.0 | 
| 1.5 | 84.0 | 86.5 | 86.5 | 75.5 | 84.0 | 86.5 | 87.5 | 77.0 | 
| 2 | 85.5 | 86.5 | 87.5 | 85.5 | 85.5 | 86.5 | 88.5 | 82.5 | 
| 3 | 85.5 | 89.5 | 88.5 | 86.5 | 86.5 | 89.5 | 89.5 | 84.0 | 
| 5 | 86.5 | 89.5 | 89.5 | 87.5 | 88.5 | 89.5 | 89.5 | 85.5 | 
| 7.5 | 88.5 | 91.0 | 90.2 | 88.5 | 89.5 | 91.7 | 91.0 | 85.5 | 
| 10 | 89.5 | 91.7 | 91.7 | 89.5 | 90.2 | 91.7 | 91.0 | 88.5 | 
| 15 | 90.2 | 93.0 | 91.7 | 89.5 | 91.0 | 92.4 | 91.7 | 88.5 | 
| 20 | 91.0 | 93.0 | 92.4 | 90.2 | 91.0 | 93.0 | 91.7 | 89.5 | 
| 25 | 91.7 | 93.6 | 93.0 | 90.2 | 91.7 | 93.6 | 93.0 | 89.5 | 
| 30 | 91.7 | 94.1 | 93.6 | 91.0 | 91.7 | 93.6 | 93.0 | 91.0 | 
| 40 | 92.4 | 94.1 | 94.1 | 91.0 | 92.4 | 94.1 | 94.1 | 91.0 | 
| 50 | 93.0 | 94.5 | 94.1 | 91.7 | 93.0 | 94.5 | 94.1 | 91.7 | 
| 60 | 93.6 | 95.0 | 94.5 | 92.4 | 93.6 | 95.0 | 94.5 | 91.7 | 
| 75 | 93.6 | 95.0 | 94.5 | 93.6 | 93.6 | 95.4 | 94.5 | 93.0 | 
| 100 | 93.6 | 95.4 | 95.0 | 93.6 | 94.1 | 95.4 | 95.0 | 93.0 | 
| 125 | 94.1 | 95.4 | 95.0 | 93.6 | 95.0 | 95.4 | 95.0 | 93.6 | 
| 150 | 94.1 | 95.8 | 95.4 | 93.6 | 95.0 | 95.8 | 95.8 | 93.6 | 
| 200 | 95.0 | 95.8 | 95.4 | 93.6 | 95.4 | 96.2 | 95.8 | 94.1 | 
| 250 | 95.0 | 95.8 | 95.4 | 94.5 | 95.8 | 96.2 | 95.8 | 94.5 | 
| 300 | 95.4 | 95.8 | 95.4 | 
 | 95.8 | 96.2 | 95.8 | 
 | 
| 350 | 95.4 | 95.8 | 95.4 | 
 | 95.8 | 96.2 | 95.8 | — | 
| 400 | 95.8 | 95.8 | 95.8 | 
 | 95.8 | 96.2 | 95.8 | 
 | 
| 450 | 95.8 | 96.2 | 96.2 | 
 | 95.8 | 96.2 | 95.8 | 
 | 
| 500 | 95.8 | 96.2 | 96.2 | 
 | 95.8 | 96.2 | 95.8 | 
 |