The movement of air from one location to another, usually measured in CFM (cubic feet per minute). It is the force exerted by the moving air which actually picks up the dirt and moves it into the bag or dirt container. This is one of the most important aspects of determining the true measure of vacuum cleaner effectiveness. Yet, sadly, few manufacturers publish these test numbers.Amperage (amps)
This is the most misunderstood and least reliable method for determining the performance of a vacuum cleaner. The maximum allowable amperage allowed by UL is 12 amps. We have vacuums that vary from 4.2 amps to 12 amps. Remember that just because a motor is rated at 12 amps does not mean that it is constantly drawing 12 amps while you are using it. This is the MAXIMUM rating. Amperage DOES NOT equal performance.Air Watts
A specification developed in an effort to rate the output power of the vacuum cleaner instead of its input power. This is actually a good indication of the efficiency of a vacuum, but it is used mostly by manufacturers of central vacuum systems. It is based on suction with air flow at the unit itself, so it is affected by the suction produced by the suction motor as well as the internal resistance to air flow. The suction and air flow are measured with the air flow being restricted by a 2” opening. Care should be taken not to confuse this suction with air flow rating or with the sealed suction rating (no air flow), which is about four times higher.
Keep in mind that the air watt rating does not necessarily reflect the actual air flow in the complete system during normal use. In addition to the resistance within the power unit and the resistance caused by air turbulence in the hose and tubing, there is restriction where the cleaning nozzle contacts the floor, as well as increased resistance within the filtering system as it fills with dirt.Beater Bar
A long stiff bar or raised section of the brush roll that is designed to separate the carpet fibers and vibrate to cause the dirt particles to be loosened and thus be available to be drawn into the vacuum by the suction and air flow. This was common on vacuums in years past but is less common today. Some commercial vacuums still have this feature, and the “beating” on non padded commercial carpet actually damages the vacuum motor and requires premature motor or bearing replacement.Brush Roll
A part of the vacuum that is cylindrical in shape and makes contact with the carpet. Its primary purpose is to agitate the carpet, separating the fibers so that dirt, embedded hair, dust, and other microscopic items lodged in the carpet fibers can be drawn into the air stream. The embedded particles might not be able to be picked up with only a strong suction and air flow; thus, the brush roll provides that action. There is usually one brush roll in a vacuum; however, some manufacturers have opted for multiple and even counter rotating brush rolls on their vacuums.Cleaning Effectiveness
There is no agreed upon definition of what this means, but there are generally two ways of viewing this. 1) The ability of a vacuum to pick up dirt from a particular surface. 2) The ability of a vacuum to pick up dirt, filter and trap it so that the dirt or allergens are not re-circulated back into your home.Cleaning “Effectiveness Rating”
Complete smoke & mirrors. This is one manufacturer’s attempt to utilize some valid and standardized tests and add some of their own criteria to make consumers believe that they were providing a better vacuum. It is confusing, misunderstood and irrelevant.Filtration
Technology has not significantly changed around the vacuum cleaner industry for many years. The concept of a vacuum motor that produces suction and air flow through the use of an electric motor has remained relatively unchanged for many years. The one exception is in the area of advanced filtration, which ensures that the dirt and allergens picked up by your vacuum STAY in your vacuum and do not get recycled and blown around your home.
The dirty air passes through a filter medium to remove it from the air. Various components that can be used in filtering systems include paper bags, nylon electrostatic filters, glass fiber paper filters, cloth or foam filters, cyclonic chambers, and even water (despite all demonstrations to the contrary, water is a very poor filter medium). Your vacuum bag is one of the most important parts of this filter system. If you use a “bagless” vacuum you must have another type of filter to trap the dust from the exhaust flow of the vacuum motor, and these must be regularly cleaned to maintain the efficiency of the vacuum.HEPA
This is among the most often referred to items that consumers want in their vacuums today. HEPA stands for “high efficiency particulate air.” HEPA is a filtering specification developed during World War II when the United States was developing nuclear weapons. We felt a need to filter out all radioactive dust and particles from sites and not have them emitted into the atmosphere. Specifically, the specification for a HEPA filter is that it must filter 99.97% of all particles .3 microns in size. Just for reference, a particle of 10 microns is invisible to the naked eye. Pollen ranges between 5-100 microns and human hair between 70-100 microns.Suction
Used broadly, suction is the ability of a vacuum cleaner to efficiently pick up dirt. When used in a more narrow way, it is the actual pull or pressure difference created by the spinning fans in the suction motor. The term suction is often used interchangeably with the term vacuum. Suction or vacuum is measured in “Inches of Water Lift” (see below). This is a very specific test and is calibrated for variances in atmospheric pressure so that all vacuum motors can be evaluated equally. Unfortunately, very few vacuum cleaner manufacturers publish these test numbers for comparison.Water Lift
The sealed suction of a vacuum cleaner as rated in inches of water lift is a good indication of how well it will perform, especially when comparing systems with higher resistance to the air flow. The air flow is proportional to the amount of suction produced by the motor and inversely proportional to the total resistance to air flow within the complete system. Therefore, if everything else is equal, the more suction produced by the motor, the better the performance of the system. The sealed suction rating is somewhat greater than the suction normally produced when operating with air flow.