Some large semi-pro electric pressure washers supply almost twice as much cleaning power as their other semi-pro counterparts. The biggest advantage these have over a comparably powerful gas unit is you can use these units inside.
Need to clean around animals or livestock? No problem.
There are no carbon monoxide emissions. Hate performing small engine maintenance? Electric pressure washers require no oil changes, fuel stabilizer, or tune-ups.
The first difference between consumer and semi-pro units is a better pump. Instead of a cheap wobble pump, you get an axial cam or triplex plunger pump. Axial cam pumps are direct drive pumps, meaning they spin at the same speed as the engine, which will wear down faster than a triplex pump.
Triplex plunger pumps are the highest quality pressure washer pumps, offering longer life and better performance. They also include a larger price tag, but if you intend to use your power washer frequently, it's well worth the expense. If the pump breaks down, you can get it rebuilt instead of having to buy a whole new washer.
If you need to clean with detergents, consider an onboard detergent tank. The alternative option is a siphon hose, which you place in a bucket of detergent and water. The more efficient option is definitely an onboard detergent tank.
A lot of cleaning projects, such as washing your siding, require detergent to get a complete clean. Just add detergent to the tank, conveniently located on your pressure washer, and you'll be able to use it without having to stop and set up a separate bucket.
Some of these large electric pressure washers require a 20-amp circuit to run. You'll want to make sure your circuit box has one of these where you'll be cleaning otherwise you won't be able to use the washer. These units come with GFCI (Ground Fault Circuit Interrupter) power cords.
They are designed to protect people from severe or fatal electric shocks because they detect ground faults and interrupt the flow of electrical current. Just make sure you have GFCI plugs.