| Number of Tubes | Front Width | Rear width | Front Height | Rear Height | Depth | BTU per Hour (max) |
| 5 Tubes (standard size) | 25" | 17" | 20 1/2" | 13 1/2" | 21" | 60,000 |
| 6 Tubes (custom size) | 29" | 21" | 20 1/2" | 13 1/2" | 21" | 72,000 |
| 7 Tubes (custom size) | 33" | 25" | 20 1/2" | 13 1/2" | 21" | 84,000 |
| 8 Tubes (custom size) | 37" | 29" | 20 1/2" | 13 1/2" | 21" | 96,000 |
| 9 Tubes (custom size) | 41" | 33" | 20 1/2" | 13 1/2" | 21" | 108,000 |
| 10 Tubes (custom size) | 45" | 37" | 20 1/2" | 13 1/2" | 21" | 120,000 |