When you're shopping for compressed air equipment in the compressors, blowers, and air treatment category, the decision usually comes down to electric continuous duty vs fuel-based portability. That fork is clear here: the Rotary Screw 15HP is an electric industrial unit, while the AllMetal 40 Gal Gas is a 9HP portable built for places without grid power. The price gap is significant too: $6,599 for the Rotary Screw 15HP and $2,699 for the AllMetal 40 Gal Gas. Here's how to match the right one to the work.
Quick Verdict
The Rotary Screw 15HP is the choice for a shop with continuous power needs. Its VSD drive keeps output matched to demand, so you get steady air without repeated start-stop cycles. The AllMetal 40 Gal Gas is the move when the job site has no electrical grid: it packs a 40-gallon tank and reaches a higher maximum pressure than the rotary screw. Choose the AllMetal for portability and pressure; choose the Rotary Screw for continuous-duty air.
At a Glance
| Feature | Rotary Screw 15HP | AllMetal 40 Gal Gas |
| Listed Price | USD 6,599.00 | USD 2,699.00 |
| Drive | 208-240V 3-Phase | 9HP gas engine |
| Max Pressure | 125 PSI | 175 PSI |
| Unit Weight | 610 lbs | 250 lbs |
Where Each Compressor Wins
The Rotary Screw wins for steady high-demand work. The AllMetal wins for on-the-go jobs where you need to bring your air supply with you.
Rotary Screw Air Compressor 15HP Industrial VSD
If your shop already has 208-240V three-phase wiring, the Rotary Screw 15HP is built to be a workhorse. The VSD controller adjusts motor speed to match how much air your tools are using, which keeps the system efficient during long shifts and avoids the constant cycling of a fixed-speed unit. It also carries UL and ASME certifications on key components, which matters for industrial environments. The trade-off is the power requirement: it needs three-phase power, so a room with only a normal household outlet will not run it. At 610 lbs, it's a heavy industrial unit. Buy it when compressed air demand is steady and high, not occasional.
AllMetal 40 Gal 9HP Gas Air Compressor
The AllMetal is the right fit when your compressor has to follow the work around. Its Loncin 9HP 4-stroke gasoline engine does not need a power connection, and the 40-gallon ASME-certified steel tank gives you a reservoir for tools like spray guns and sandblasters. The 175 PSI maximum pressure is higher than the rotary unit's rating, and the 14.5-20.6 CFM flow rate is practical for one heavy tool or a few lighter ones. The limitation is that it can't feed a high-volume shop the way a bigger electric unit can, and you'll be tied to fuel and engine upkeep. If your site changes from week to week, this is the portable option.
Final Choice by Use Case
Choose the Rotary Screw 15HP for shop work with long operating hours. Choose the AllMetal 40 Gal Gas for off-grid sites where portability and high pressure matter most.
