The following terms are used throughout the vacuum industry to describe both central vacuums & portable units. It’s important to remember that each company has control over which terms they use to describe their products.
This number represents the amount of electrical current consumed by the motor during use. The implication is that the more electricity the motor uses, the more powerful it is. This is not necessarily true. A simple analogy would be a car using more gas should be more powerful. While this may be true, it may also be true that the car really needs a tune-up. In other words, when the current is not being used efficiently, amps are a poor indicator of cleaning power.
Peak horsepower is also a poor indicator of cleaning power. Again, the message to the consumer is the more horsepower the motor has, the better. However, this may or may not translate into usable power. It is interesting to note that peak horsepower never really exists for the consumer in any usable manner. It is a value measured in labs with very sensitive instruments, and only exists for a tiny fraction of a second.
CLEANING EFFECTIVENESS PER AMP
This controversial claim represents neither cleaning power nor amps. It has some limited value for people who are concerned with how much cleaning their vacuum does for the electricity consumed. As you know, most consumers just want the cleanest room possible when vacuuming. They typically would not compromise cleanliness because their vacuum pulled two more amps during a half-hour of cleaning. There is little or no correlation between Cleaning Effectiveness per Amp and Cleaning Power.
CFM (CUBIC FEET PER MINUTE)
Some vacuum systems are sold on their credentials for high CFM. However, maximum CFM ratings occur when the vacuum system is wide open with no restriction to airflow. Most consumers add a hose (canisters or central vacs) and some type of cleaning attachment which restricts airflow. Therefore, maximum airflow can be misleading because consumers do not vacuum under maximum airflow conditions.
ASTM (American Society for Testing and Materials) is the industry recognized authority on cleaning power. ASTM is a professional organization consisting of members from industry, universities and even consumer groups. Hoover, Eureka®, Beam®, Electrolux®, Royal®, H-P Products® and even Good Housekeeping all send representatives to ASTM. This group of professionals works together to develop industry standards for fair and accurate testing.
According to ASTM, cleaning power is best measured in air watts. Like electrical watts, air watts is a measure of the ability to do work (in this case, remove dirt). In vacuum cleaners, air watts are calculated after measuring the suction at different size openings. It is most important to measure air watts at openings between 1/2" and 7/8" diameters. This range represents using common attachments such as a floor brush, crevice tool or power head. In simple terms, air watts takes into account both CFM and water lift by representing their combined power. It’s important to remember that both vacuum and CFM are critical elements of cleaning power.
Sometimes referred to as maximum waterlift, this value represents how high (in inches) a vacuum cleaner will lift water up a cylinder. It can be measured with a simple hand held gauge, but usually is still represented in inches of water. Unlike air watts, sealed vacuum is a poor indicator of cleaning power because there is no airflow in a sealed condition. Unfortunately, many consumers don’t realize this. Sealed vacuum is frequently used as a sales tool because it seems "obvious" that the more suction a vacuum cleaner has, the better it works. However, a simple test will show that high suction with zero airflow won’t clean anything.
The best method to demonstrate this to consumers is a comparison of sealed vacuum to working vacuum. Using a vacuum gauge and test Y, you can measure the suction of a vacuum while air is flowing through an opening which best represents the use of a hose and attachments.
While sealed vacuum is great tool for identifying leaks in a vacuum system, working vacuum is a great way to demonstrate sustained cleaning or lack thereof. All vacuum systems have to deal with fine dust particles, and the type of filtration will largely impact how long the system can operate before these particles impact its performance.