In order to understand the pressure washer features, it is important we first understand the terms used to rate their cleaning power.
PSI, simply means (pounds per square inch), and is the units of measurement that the industry uses to rate cleaning force of a pressure washer. To help understand exactly what the PSI rating means, look at how it works for us.
1. 1,000 - 1,500 PSI: is a good choice for washing our cars, pick-up trucks, bicycles, lawn mowers, patio furniture and our barbeque grills
2. 1,400 - 1,850 PSI: appropriate to use when cleaning a brick patio, small deck and wood fence.
3. 2,000 - 3,000 PSI: more power for cleaning a large wood deck or washing aluminum or vinyl siding.
4. 2,800 - 4,000 PSI: is by far the best choice for cleaning stained concrete driveways, sidewalks and patios or stripping loose, blistered and flaking paint off the concrete wall, porch and garage floor.
GPM, (gallons per minute) in therating of a pressure washer, is the measurement used to tell us exactly, how much water the pump on the power washer uses every minute we use it when cleaning. The experts agree, the higher GPM rating, the better an electric pressure washer will clean.
CU, (cleaning units) is calculated by multiplying a pressure washers PSI by the GPM. The more CU (cleaning units), a pressure washer cleans much more efficiently. For instance, consider an electric powered pressure washer rated at 1500 PSI and .7 GPM.
To calculate the CU (cleaning units) of a pressure washer, use the 1500 PSI and multiply it by the .7GPM, which equals 1050 CU (cleaning units); now let us compare that to a similar power washer with the same 1500 PSI, but increase the GPM to 1.5.
After we do the math, WOW we discover the CU (cleaning units) increases to 2200 CU, which has more than doubled the cleaning units of the pressure washer with the higher GPM rating, subsequently doubling the pressure washers cleaning capability.
Garden Hose, consider this little fun fact, city water comes into our homes anywhere from five to seven GPM, and somewhere between forty and fifty PSI, rural county water is more often than not less than that. This relates to a whopping, 280-350 CU (cleaning units) available, maximum, if you live in a rural area your water may be less than half that. To check your GPM, use a five-gallon bucket and fill it with your garden hose, see how long it takes to fill the bucket. If the 5-gallon bucket has filled in 60 seconds, you have five GPM (gallons per minute).