Peak horsepower is the maximum output horsepower of a motor determined from a laboratory dynamometer test. Since peak horsepower is outside the normal operating range of a vacuum cleaner, it may not be indicative of actual air power differences when comparing two cleaners.
Working tank capacity may vary based on use.
SP (Sealed Pressure):
Suction pressure represents how far up a glass tube a vacuum motor will lift a column of water. This function is measured in inches. Maximum suction pressure or sealed water lift is obtained at zero air flow. Suction pressure decreases as air flow increases.
CFM (Cubic Feet Per Minute):
CFM is a measure of the quantity of air moved by the vacuum motor at a particular system load, such as 2-1/2" orifice. Your actual system load is determined by the type, size and length of the hose used, the accessory tool used and the filter system used. A dirty filter system can drastically affect the suction and air flow. The filters need to be cleaned regularly and replaced as necessary to avoid reduced suction and air flow.
Vacuum performance or air power is the rate of work performed by a vacuum cleaner. Air power is a function of suction and air flow at an operating point. Air power is reduced by dirty filters, leaks and attachments used.