13 of 13 variants have co₂ emissions data.
| Variant | Year | Body | Fuel | CO₂ emissions |
|---|---|---|---|---|
| Hummer H3 3.5 Comfort | 2006 | SUV | Petrol | 369 g/km |
| Hummer H3 3.5 Comfort | 2005 | SUV | Petrol | 369 g/km |
| Hummer H3 3.5 Advantage | 2005 | SUV | Petrol | 369 g/km |
| Hummer H3 3.5 Advantage | 2005 | SUV | Petrol | 369 g/km |
| Hummer H3 3.5 Executive | 2005 | SUV | Petrol | 369 g/km |
| Hummer H3 3.5 Executive | 2005 | SUV | Petrol | 369 g/km |
| Hummer H3 3.7 Adventure | 2007 | SUV | Petrol | 348 g/km |
| Hummer H3 5.3 V8 Luxury | 2008 | SUV | Petrol | 344 g/km |
| Hummer H3 3.7 Adventure | 2007 | SUV | Petrol | 330 g/km |
| Hummer H3 3.7 Luxury | 2007 | SUV | Petrol | 330 g/km |
| Hummer H3 3.7 | 2007 | SUV | Petrol | 320 g/km |
| Hummer H3 3.7 Luxury | 2007 | SUV | Petrol | 320 g/km |
| Hummer H3 3.7 | 2007 | SUV | Petrol | 314 g/km |