Greenworks 40V 21" Brushless Cordless (S vs SENIX Gas Lawn Mower, 22" Self Propelled
Quick Verdict
If you value quiet operation, zero emissions, and low maintenance, choose the Greenworks 40V 21" brushless cordless mower. If you need maximum power for thick, wet grass or a larger yard without worrying about battery runtime, choose the SENIX 22" gas mower. Both are similarly priced, but their strengths suit very different use cases.
Side-by-Side
| Feature | Greenworks 40V 21" Cordless | SENIX 22" Gas |
|---|---|---|
| Price | $399.99 | $395.10 |
| Power Source | 40V battery (brushless motor) | Gas engine |
| Cut Width | 21 inches | 22 inches |
| Self-Propelled | Yes | Yes |
| Best Yard Size | Up to 1/3 acre (per charge) | 1/3 acre and larger |
| Weight | ~65 lbs (with battery) | ~75 lbs (with fuel) |
| Noise Level | Quiet (approx. 75 dB) | Loud (approx. 95 dB) |
| Emissions | Zero | Gas fumes |
| Maintenance | Minimal (blade sharpening, battery care) | Oil changes, spark plug, air filter, fuel stabilizer |
Where Greenworks Wins
The Greenworks mower excels in convenience and ease of use. Its brushless motor is more efficient and durable than brushed motors, providing longer runtime and less heat buildup. You never have to deal with gas, oil, or pull cords—just press a button and mow. It is significantly quieter, making it neighbor-friendly and usable at any hour. The 40V battery system is compatible with many other Greenworks tools, so if you already own their leaf blower or trimmer, you can share batteries. At 65 pounds, it is lighter than the SENIX, which makes maneuvering and storing easier. It also requires far less maintenance: no oil changes, no spark plugs, no fuel to stabilize. For yards up to about 1/3 acre, a single charge is usually enough, and the 21-inch cut is standard for residential lawns.
Where SENIX Wins
The SENIX gas mower delivers raw power that cordless mowers cannot match. The 22-inch cut width is one inch wider than the Greenworks, meaning slightly fewer passes per lawn. Gas engines maintain full power regardless of battery charge level, so you never experience the power fade that some cordless mowers show as the battery drains. This mower handles thick, damp, or overgrown grass without bogging down—something that can challenge a 40V battery mower. It is also better for larger yards (over 1/3 acre) because you only need to refuel, not wait for a battery to recharge. The self-propelled drive on the SENIX is typically more responsive for steep slopes or heavy grass. If your property has many obstacles or uneven terrain, the extra torque from the gas engine can make a noticeable difference.
Which Should You Buy
Choose the Greenworks 40V 21" if you have a small to medium yard (up to 1/3 acre), want a quieter, cleaner mowing experience, and prefer low maintenance. It is ideal for homeowners who already own Greenworks 40V tools or want to build a battery-powered ecosystem. It also suits those who dislike gas engine upkeep or live in areas with noise restrictions.
**Choose the SENIX 22" gas mower if you have a larger yard (over 1/3 acre), frequently mow wet or heavy grass, or need maximum power for tough conditions. It is the better choice if you are comfortable with gas engine maintenance and want a mower that will not lose power as the battery drains.