Manufacturer-documented fuel consumption for 35 20–25 kW Bi-Fuel (NG/LP) generator sets — median 3.46 gal/h at full load, 2.36 gal/h at half load.
Compare 20–25 kW Bi-Fuel (NG/LP) generator specs side-by-side →
| Model | kW | gal/h @ 50% | gal/h @ 100% | Tank (L) | Runtime @ 50% (h) |
|---|---|---|---|---|---|
| Briggs & Stratton PP20 | 20 | 2.30 | 3.70 | — | — |
| Cummins/Onan RS20A | 20 | 1.45 | 3.01 | — | — |
| Generac 7038 | 20 | 0.87 | 1.37 | — | — |
| Generac G007038 | 20 | 2.36 | 3.56 | — | — |
| Generac G007038-0 or G007039-0 | 20 | 2.52 | 2.94 | — | — |
| Generac G007039 | 20 | 2.36 | 3.56 | — | — |
| Generac G007040-0 | 20 | 1.79 | 3.46 | — | — |
| Generac G007041-0 | 20 | 1.79 | 3.46 | — | — |
| Generac G007077-0 | 20 | 2.39 | 3.56 | — | — |
| Generac G007077-1 | 20 | 2.39 | 3.56 | — | — |
| Generac Guardian 20 kW | 20 | 2.37 | 3.56 | — | — |
| Generac QT020 | 20 | 0.79 | 1.13 | — | — |
| Kohler 20RCA | 20 | 1.22 | 2.11 | — | — |
| Kohler 20RES | 20 | 0.48 | 0.61 | 15 | 8.3 |
| Cummins/Onan RS 22 | 22 | 2.00 | 3.10 | — | — |
| Generac 7042 | 22 | 0.26 | 0.39 | — | — |
| Generac G007042 | 22 | 2.36 | 3.56 | — | — |
| Generac G007042-0 or G007043-0 | 22 | 2.52 | 2.94 | — | — |
| Generac G007043 | 22 | 2.36 | 3.56 | — | — |
| Generac Guardian 22 kW | 22 | 2.37 | 3.56 | — | — |
| Generac In Line 4 | 22 | 26.42 | 67.36 | — | — |
| Generac QT022 | 22 | 1.81 | 3.29 | — | — |
| Generac QT02224 | 22 | — | 0.90 | — | — |
| Generac RG022 | 22 | 0.55 | 0.90 | — | — |
| Generac RG02224ANAX | 22 | — | 2.10 | — | — |
| FG Wilson UHG24E1S | 24 | 1.19 | 7.50 | 405 | 90.0 |
| FG Wilson UHG30E1 | 24 | — | 2.50 | — | — |
| Generac 7209 | 24 | 0.26 | 0.39 | — | — |
| Generac G007209-0 | 24 | 2.36 | 3.56 | — | — |
| Generac G007209-10 | 24 | 2.36 | 3.56 | — | — |
| Generac G007210-1 | 24 | 2.36 | 3.56 | — | — |
| Generac G007210-10 | 24 | 2.36 | 3.56 | — | — |
| Generac Guardian 24 kW | 24 | 2.37 | 3.56 | — | — |
| Kohler 24RCL | 24 | 1.80 | 2.39 | — | — |
| Kohler 26RCA | 24 | 5.10 | 8.20 | — | — |
Figures from each model’s own manufacturer documentation (spec sheets and manuals); runtime = documented tank capacity ÷ consumption at 50% load. Verify against the datasheet for your exact configuration.
Across 35 models with manufacturer data, full-load consumption runs 0.39–67.36 gal/h (median 3.46); at 50% load the median is 2.36 gal/h.
At 50% load, documented tank sizes give 8.3–90.0 hours (median 49.2 h) across 2 models.