What three features are vital for the best type of vacuum cleaner? The three main stages are agitation, suction and capture.

First up is how well it loosens the dirt. The best for this are the upright vacuums which have one or two sets of brushes for agitation Some use a brush driven by the same motor as the vacuum motor but the best ones have a separate motor.That's all extra power to rip the dust and dirt out of the carpet. Most people can tell visually if one or the other has been used Most people agree that the fibres are raised and separated more with a dual drive system

The second thing to look at is how the machine lifts the dirt.In other words, how effective the vacuum system is.The two most typical filtration systems are bags or cyclones.

As a bag or filter has to stop dust physically, it will also start to get blocked.Once they are about a quarter full, their power of suction will drop dramatically.

Cyclonic separators are a step forward in air cleaners. These may have several filters in line, each removing a different sized dirt particle.The cyclone, in comparison, extracts the dust by spinning it really quickly so that it gets thrown out from the side.This gets around the problem of the bags clogging up.

In my years doing business with carpet cleaners Birmingham, I've found that healthwise, is the one that is most significant to health.

Once we have solved that problem, we have to look at how it holds on to the dust and dirt that has been removed.If you do not contain and remove this dust you could be breathing it back in almost straight away. Some can be fine enough to cause you some real problems.Very small particles of dust are very hazardous to your health.

You have to look for a system that contains as much as possible.A great way to keep the indoor air clean is to use water to hold onto the dirt.This method works by directing the dirt filled airflow down on to the surface of the water where it is captured and cannot be sent back up into the air.The best type of vacuum cleaner to take advantage of this system is the tub. The machine has to be kept level to make the most of this really effective filtration method.

The dust and dirt is sucked into the machine where it is trapped by the water as it blows across. Once in, it cannot escape back into the atmosphere.

What would be the best way to design a vacuum cleaner (assuming that patents were not a problem)?

After reading the above you would, no doubt, go for the best features of each variation. For instance, you would want the increased agitation from a separate brush motor. You would want the high airflow of a cyclone (or possibly a water system). You would also want the "air washing" performance of a water filtration vac. Can you have all these together? No (well let's say maybe).Having a water filtration system on an upright is fraught with danger because the water has to be kept level. If you do not, the water will enter the vacuum motor and destroy it in seconds. The very action of moving the handle backwards and forwards means that the water rocks back and forth. This effectively rules out a water filtered upright. Or does it?

You could compromise and go for a water filtration vacuum with a separately powered electrical brush head.

Whatever you decide, please take the filtration aspect seriously. It could, in the long run, be a life saver.