Greenworks 40V 21" Brushless Cordless (S vs SENIX 22 Inch Gas Lawn Mower, 201cc 4-Cy

Greenworks 40V 21" Brushless Cordless (Self-Propelled) Lawn Mower (75+ Compatible Tools), 5.0Ah Battery and Charger Included
Greenworks 40V 21" Brushless Cordless (Self-Propelled)...
$399.99
★ 4.1/5 · 1527 reviews
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SENIX 22 Inch Gas Lawn Mower, 201cc 4-Cycle OHV Engine, Variable Speed Rear Wheel Self-Propelled Mower, 3-in-1 Mower with Bagging, Mulching & Side Discharge, 6-Positions Adjustable Cutting Height
SENIX 22 Inch Gas Lawn Mower, 201cc 4-Cycle OHV Engine,...
$509.99
★ 4/5 · 343 reviews
Read full review →
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Quick Verdict

For most homeowners, the Greenworks 40V cordless mower is the better choice, offering strong performance, lower cost, and less maintenance. The SENIX gas mower wins only if you need maximum power for thick, wet, or overgrown grass on a larger property, and you don’t mind the extra upkeep.

Side-by-Side

Feature Greenworks 40V 21" Brushless Cordless SENIX 22" Gas 201cc
Price $399.99 $509.99
Power Source 40V battery (cordless) 201cc 4-cycle gas engine
Cut Width 21 inches 22 inches
Self-Propelled Yes Variable speed (likely self-propelled)
Best Yard Size Up to 1/2 acre (with extra battery) 1/2 to 1 acre
Weight ~55 lbs (with battery) ~80 lbs
Maintenance Minimal (no oil, gas, or spark plugs) Regular (oil changes, fuel, air filter)

Where Greenworks Wins

Lower upfront cost – $110 less than the SENIX, with no future fuel or oil expenses.

Much less maintenance – No gas, oil, spark plugs, or carburetor cleaning. Just charge the battery and store it.

Lighter and easier to maneuver – About 25 lbs lighter, making it simpler to push, lift, and store.

Quieter operation – Cordless motors are far quieter than gas engines, so you can mow early or late without disturbing neighbors.

Instant start – No pull cord, no choke, no priming. Press a button and go.

Zero emissions – No exhaust fumes, better for you and the environment.

Good for smaller to medium lawns – The 40V system with a 4.0Ah or larger battery can handle up to 1/2 acre on a single charge, especially if you mow frequently.

Where SENIX Wins

More raw power – The 201cc gas engine delivers higher torque, cutting through thick, wet, or tall grass without bogging down.

Wider cut – 22 inches vs. 21 inches, so you cover slightly more ground per pass. This adds up on larger lawns.

Unlimited runtime – As long as you have gas, you can keep mowing. No waiting for batteries to recharge.

Better for large or rough terrain – If your yard is over 1/2 acre, uneven, or has heavy brush, the gas engine’s consistent power is an advantage.

More familiar to traditional users – If you’re used to gas mowers and prefer the sound and feel, the SENIX won’t require a change in habits.

Which Should You Buy

Buy the Greenworks 40V if:

  • Your lawn is 1/2 acre or smaller
  • You want lower cost and less maintenance
  • You prefer quiet, clean, and easy operation
  • You’re comfortable managing battery charging and occasional battery replacement (every 3–5 years)

Buy the SENIX 22" Gas if:

  • Your lawn is larger than 1/2 acre (especially 3/4 to 1 acre)
  • You often mow thick, wet, or overgrown grass
  • You don’t mind regular engine maintenance and fuel storage
  • You need unlimited runtime for a single mowing session

Bottom line: For the vast majority of suburban homeowners, the Greenworks offers the better value – it’s cheaper, easier, and plenty capable. The SENIX is a specialized tool