How to choose a cordless power washer
Eight checks, in the order I would run them, from twenty years of cleaning exteriors for a living.
1. Decide what you are actually cleaning
Write down the last five cleaning jobs you did. If they were mostly rinsing dirt, mud, pollen, salt or light algae off surfaces within reach, a cordless washer is the right purchase. If they involved stripping paint, degreasing a workshop or restoring timber, buy a corded or gas machine instead.
2. Pressure and flow are a pair
Pressure breaks the bond between dirt and surface; flow carries it away. A unit with high pressure and stingy flow works in a narrow stripe and feels slow. For household maintenance, 1,000–1,500 PSI with decent flow handles the overwhelming majority of jobs.
3. Nozzle options beat extra PSI
A machine with jet, fan and wide-rinse modes is more useful than a machine with 200 more PSI and one nozzle. The same tool needs to be aggressive on mortar joints and gentle on car paint, and only the nozzle makes that switch.
4. Check the water source, not just the tap
A self-priming intake that draws from a bucket, sink, pool or stream is the single most valuable feature in this category. It is what makes balconies, campsites and driveways far from a spigot possible at all.
5. Do the battery maths honestly
Two 4.0Ah packs typically mean about 30 minutes of work; two 4.5Ah packs stretch nearer an hour on light duty. Decide whether your typical job is a car (fine) or a full driveway plus fence (plan for charging), and buy accordingly.
6. Weight is an ergonomics spec
Anything under about 3 lb can be used one-handed above shoulder height, which matters for windows, gutters and soffits. Heavier units are fine on the ground and miserable overhead.
7. Count what ships in the box
A foam cannon, hard case, adapters and spare battery are easily $80–$100 bought separately. A cheaper unit without them is often not cheaper at all — this is where the #1 pick's bundled gifts change the comparison.
8. Watch for the warning signs
Parent-ASIN listings with price ranges, review counts under 50, no stated availability, and specs that quote pressure without flow. Any of those means you are buying on marketing copy rather than data.