Identifying Good Performance Factors

Like many other household appliances, a vacuum cleaner is designed to enable its user to more easily and effectively perform specific tasks. A vacuum cleaner uses air flow, often combined with brushing action, to pick up various dirt, dust, allergens, etc. Not only does it need to be efficient in picking up these objects, but it must also be efficient in removing them from the air so they are not recirculated back into the living environment. Since many manufacturers do not publish performance related specifications, it is often difficult to determine which vacuum cleaner will actually be the best performer in you specific situation.

The performance of the filtration system is affected by the efficiency of the paper bag and additional filters as well as the cleaner's ability to ensure that all the air actually passes through every filter. The ability of a vacuum cleaner to deep clean carpeted floors is affected primarily by three factors: the design of the nozzle, the velocity of the moving air in the nozzle and the agitation of the carpet fibers by a revolving brush roll. There are many factors which affect the filtration efficiency and cleaning efficiency as described below and in related articles. The durability of vacuum cleaners is discussed in our article titled "Identifying Durable Designs & Construction."

Filtration Efficiency - HEPA, Micron, etc.

The current cutting edge in vacuum cleaner technology is in the area of improving the filtration efficiencies of vacuum cleaners. The vacuum cleaner industry is taking advantage of the development of advanced filtration media to provide much higher quality exhausted air than was available just a few years ago. Where there are special dust related sensitivities like allergies and asthma, vacuum cleaners which have extremely high filtration efficiencies that meet the HEPA specifications are often very helpful. Some commercial vacuums provide ULPA Filtration which efficiently traps even smaller particles. When the extremely low dust emissions provided by HEPA and ULPA filters aren't necessary, Micron filtration can still provide very clean exhausted air. It is very important to have a completely sealed system from input to exhaust so all air flow must pass through the high efficiency filter to be cleaned by it.

For more information on factors affecting filtration efficiency, see our articles on Filtration Efficiency - HEPA, Micron, etc. and the Efficiency of Paper Bags.

Filter Construction and Design

Increasing the area of the filter media increases the vacuum cleaner's ability to move air through it. This is especially important for the first (primary) filter after the dirt container in bagless vacuums. I have seen many bagless vacuums brought to us with the complaint of very poor cleaning performance. A quick check of all the filters usually reveals a very clogged filter, often with very small area. Most bagless vacuums are made in China and are very poorly designed including very poor filtration systems. The primary filter is often a flat foam filter about 5" in diameter that provides very little filter media area. An alternate to this is a band about 2" wide and 5" in diameter which also has the same major problem. Companies often place a fan-fold filter after the foam filter to trap smaller particles. However, the foam filter becomes coated and clogged very quickly after it is cleaned. This is one major reason to purchase a vacuum with disposable bag instead of a bagless vacuum. A bag typically has a much larger filter media area plus bag movement and air flow within the bag reduces the coating and clogging effect.

Efficiency of Paper Bags

When it comes to cleaning performance, there is a tendency to look primarily at the power of the suction motor and the amount of bristles on the brush roll. While these are important considerations, the quality and size of the paper bag are very important factors as well. The quality of the bag's filter media affects both its ability to retain the fine dust and allergens as well as its ability to allow air to easily flow through it. A good quality paper bag is a very important vacuum cleaner component. Care should be taken to always replace it with an equally high quality paper bag so good vacuum cleaner performance is maintained.

Since Ristenbatt Vacuum Cleaner Service understands how very important it is to use good quality paper bags, we recommend those distributed by the Original Equipment Manufacturer (OEM or Genuine) of the vacuum cleaner for maximum performance and minimum problems. To learn more about paper bag performance, see our article titled "Efficiency of Paper Bags."

Identifying Factors Which Affect Air Flow

The air flow, combined with agitation, is one of the most important aspects of picking up dirt with a vacuum cleaner. It is the force exerted by the moving air which actually picks up the dirt and moves it into the bag or dirt container. The motivating factor for the air flow is the suction created by the fan in the suction motor. The limiting factor is the total resistance to air flow throughout the vacuum cleaner. Ideally, you want to have the highest possible velocity of air flow in the area of the nozzle where the dirt is being picked up.

Air flow is rated in cubic feet per minute (CFM). When you see air flow ratings, the measurement is often taken at the inlet of the vacuum cleaner. As such, it is always measured with a completely clean filtration system so the internal resistance is at its absolute minimum. Unfortunately, this measurement does not accurately reflect what the actual air flow velocity in the cleaning nozzle will be in typical cleaning situations. Factors like the amount of suction developed by the suction motor, the amount of resistance in the filtration system as it traps the dirt, the total amount of resistance in all air passages as well as the design of the cleaning nozzle will significantly affect the vacuum cleaner's ability to pick up the dirt.

For a more detailed presentation about the factors which affect air flow, see our article on Air Flow through the System.

Suction Motor and Fan Performance

The suction motor is one of the most important parts of a vacuum cleaner. It is this motor which takes the electrical power from the power source and converts it into mechanical power in the form of suction with air flow. Rating the motor for its ability to produce suction with air flow is one of the most misrepresented and misunderstood aspects of vacuum cleaner technology. This confusion has been accentuated by many manufacturers in their attempt to make their products appear superior to others. Various methods of rating the suction motor's performance are discussed in our article on the Power of the Suction Motor. For more about the physical design of suction motors, see our articles on Suction Motor Design & Operation.

There are two basic vacuum cleaner fan designs. The first type is used in the traditional upright design while the other type is used in all other designs including the "clean-air" upright, two-motor upright, two-motor power team, standard canister and central vacuum system. For more about these two types of fans, read our article on Fan or Impeller Types & Perfomance.

For many years motors containing at least two fan stages pulling in series were used since they created the most suction. Then around the 1970s a number of manufacturers developed less expensive 1-fan motors for their competitively priced vacuums. This was particularly true of most models found in department stores and mass merchants. Today some newer high performance motor designs incorporate one fan which is much thicker near its center so more air can enter its blades. An example of this is the Miele Vortex Motor and the motor used in some other high performing canister vacuum cleaners. The 1-fan design significantly reduces resistance to air flow within the motor so higher system air flow is obtained.

Cleaning Nozzle Design Considerations

The design of the cleaning nozzle can have a significant effect on a vacuum cleaner's ability to clean effectively. It is the force exerted by the air flow combined with agitation, that actually picks up the dirt at the cleaning nozzle. The higher the velocity of the air flow close to the surface being cleaned, the better the cleaning performance will be. The smaller the area through which the air flow is passing, the greater the velocity will be. For this reason most nozzles, especially carpet nozzles without revolving brush rolls, have fairly narrow openings across their full width. To remove dirt and grit embedded deep within a carpet is virtually impossible using air flow alone so uprights and power nozzles with revolving brush rolls were developed.

The air flow velocity should be similar across the full width of the nozzle so all areas are cleaned well. Most cleaning attachments have funnel shaped air passages which lead to centered hose or wand connectors. Uprights which use a similar design for outstanding performance are the Lindhaus upright, Commercial and Heavy Duty Sanitaire uprights and Kirby uprights. Most power nozzles used on power teams have center mounted air inlets so air flow is fairly uniform across their full width as well. Unfortunately, many uprights with on-board attachments have brush roll housings with the air inlets very close to one of their sides so the air flow velocity is significantly greater on that side compared to the opposite side. For a more detailed description of various nozzle designs and how they affect performance, see our article on Cleaning Nozzle Design Considerations.

Enhanced Cleaning with Revolving Brush Rolls

The beauty, warmth and softness of carpeted floors have made them very attractive to many people. With carpet comes the challenge of removing the grit, dirt and dust that somehow find their way deep into the carpet nap. Over the years vacuum cleaners have advanced to the point that they are very capable of removing these items and preventing them from being recirculated back into the living environment. Grit, with its sharp edges and corners, is one of the primary causes of carpet wear. The revolving brush roll was developed to make a huge difference in the effectiveness of a vacuum cleaner in removing this deeply embedded dirt. Its high speed brushing action and agitation also fluff the carpet nap, giving it a fresher, newer look.

Most manufacturers use plastic, acrylic or wooden brush rolls with the bristles embedded into the roll itself. Some of the higher quality vacuum cleaners use steel brush rolls with replaceable brush strips and ball bearings. Brush rolls come in many shapes and sizes, some are round, others are contoured or auger shaped. Some have few bristles and no beater bars, others have many bristles plus beater bars. Even the speed at which they rotate varies from model to model, some as high as 6,500 RPM. Don't let the speed of the brush roll mislead you though. Some of the fastest revolving brush rolls have very few bristles on them.

By using a motor driven revolving brush roll, carpet cleaning is much, much better than using a standard carpet nozzle having only a stationary brush strip. Ease of use is greatly improved as well. Revolving brush rolls are found in all Traditional Uprights, most "Clean-Air" Uprights, all Two-Motor Uprights, all Two-Motor Power Teams as well as some Hand Held Vacuum Cleaners. For more about the use of revolving brush rolls, see our article on the Effects of Brushing Action.

The aggressiveness of a revolving brush roll goes a long way toward its ability to deep clean carpets but this can be harmful to some carpets like Berber and delicate oriental carpets if the bristles are too harsh. A number of manufacturers of Berber carpets do not recommend using a revolving brush roll on them since the tops of the loops can be damaged. A type of cut Berber instead of looped Berber has recently become available which has the durability of Berber but with less risk of damage from a revolving brush roll. We recommend that you check with the manufacturer or their representative to determine whether to use a revolving brush on Berber or delicate oriental carpets. If you choose to use a revolving brush roll on delicate carpets, we recommend the Miele SEB 217-3 Powerbrush which are available with some Miele Power Teams since its long soft bristles are fairly gentle on the carpet fibers.

Compromises with Modern Upright Designs

Today's modern upright designs are quite different from the traditional upright design used for many years. The vacuum cleaner industry has developed it to the extent that it has become like the Swiss Army Knife, being able to tackle almost any cleaning task. They have added on-board attachments, reduced the weight, added more bristles to the brush roll and increased the motor power substantially. Most uprights made today have motors which are rated between 7 and 12 amps. The Oreck 8 lb. upright is an exception worth noting since it only has a 4 amp. motor. Perhaps this should be expected for its light weight, but for its price, the customer deserves much more. The maximum amperage permitted for UL Approval of an upright vacuum cleaner is 12.0 Amps. If you see a rating higher than that, it probably is an Efficiency Rating.

By trying to combine the ability to do all cleaning task into one cleaner, the industry has made quite a few design compromises. While the motor is quite powerful, the fan is often a fairly small diameter so its efficiency is reduced. At the same time, the air passage leading from the main cleaning nozzle is typically located near one side so the air flow isn't very uniform across the full cleaning width. On-board attachments are quite convenient for quickly cleaning your furniture or a corner here or there but hose lengths are often too short and cleaning bare floors with them is very inconvenient, if not almost impossible.

A number of manufacturers state that their upright cleaners can be used to clean bare floors with the main nozzle but few will do really well on non-carpeted floors. Some modern uprights have the ability to stop the brush roll for cleaning bare floors and use with the attachments. This is beneficial in preventing the dirt and grit from being whipped back on bare floors before the air flow can pick it up. Better yet is the option like on some Lindhaus and SEBO uprights that enables you to replace the main nozzle with a floor brush.

Since the motors are quite powerful on most modern uprights, they are able to clean quite well on carpets. Be careful to avoid the impression that they will do as well on bare floors or that they are convenient for cleaning large areas with the attachments. Some manufacturers, like Sanitaire are still making heavy duty traditional uprights that often perform better than the modern upright designs for cleaning carpet and can easily be teamed with a compact canister to efficiently clean everything else.

Factors Effecting the Loss of Performance with Use

While purchasing a vacuum cleaner with sufficient power for its cleaning task is important, so is selecting one which is designed to perform well with minimal loss of performance with use. The vacuum cleaners being used in most homes today are not performing to their best ability. The three major causes of reduced performance are reduced air flow through the filtration system, stretched and slipping belts and worn or soft bristles. As a courtesy, Ristenbatt Vacuum will perform a FREE in-store Annual Vacuum Cleaner Performance Checkup on most household vacuums, typically while their owners wait.

Take a close look at the size of the paper bag and any filter media through which the air travels. The larger the media area, the less resistance to air flow will be experienced as the bag fills and as filters become soiled. High efficiency filters which meet the stringent HEPA or ULPA filtration specification have extremely large areas so they are fan folded into cartridges small enough to fit into the cleaners. It is important to have a number of prefilters before the HEPA or ULPA filter to prevent them from becoming soiled rapidly, requiring frequent replacement. One of the best vacuum cleaner filtrations systems for home use is the completely sealed system with Certified HEPA filtration that the Miele S2, S6 and S8 Canisters provide. Miele's revolutionary new AirClean™ bag, with its intricate web of random-spun polymer fibers, retains far more tiny particles and allergens than with conventional paper bags. This high filtration bag, combined with their Certified HEPA Filter and completely sealed system enabled these vacuums to have their complete system certified that it meets the stringent HEPA specification. To obtain the best performance with the least problems, use supplies make by the manufacturer of your vacuum cleaner. They are well worth the additional cost.

Most uprights and power nozzles use a flat stretch type rubber belt to transfer the power from the motor to the revolving brush roll. Since these will gradually stretch and slip more as time goes by, they should be replaced at least once a year to maintain good performance. Some of cleaners have non-slip cog type belts including all Miele power teams, all Lindhaus uprights and power teams, all SEBO uprights and power teams and all Aerus (formerly Electrolux) uprights and power teams. This superior design eliminates belt slippage for better carpet agitation and extends the belt life to about five to seven years. A variation to this is the Reinforced Banded V-belt similar to those used on a car engine. These also are reinforced so they can not stretch and slip. Cog and Banded V-belts typically are more narrow so less space on the brush roll is used by the belt, providing more room for the bristles.

Bristles, especially on revolving brush rolls, wear shorter and become softer with use. These should be replaced about every five years to keep good performance. Some brush rolls have the bristle secured into wooden or acrylic brush rolls while others are steel with replaceable brush strips. The cost of replacing bristles in the latter type is often less expensive than replacing the complete brush roll. Well designed brush roll bearings and mounts are important, expecially with plastic or acrylic brush rolls, since bearing failure can easily cause the roll to melt and require replacement. Lower priced vacuum cleaners often have poor roll bearing designs and acrylic rolls which require more frequent replacement.

By looking for good designs in the vacuum cleaner system and performing a few minor maintenance tasks, your new vacuum cleaner can operate near its peak performance over its entire life span. For more detailed information about factors which reduce cleaning performance, see our article on Loss of Performance with Use.

Concluding Remarks

As you can see from the above, determining which vacuum cleaners will perform the best for your particular cleaning needs can be a difficult and complex task. There is a lot more to consider than just the amperage, suction (water lift) or air flow ratings when comparing vacuum cleaners.

By shopping at a vacuum cleaner specialty store like Ristenbatt Vacuum Cleaner Service, knowledgeable salespeople can show a broad range of vacuum cleaners to you including those which are designed to have outstanding performance in both cleaning and filtration. Your chances of making the best purchase for your particular cleaning needs is greatly increased when you talk face to face or on the phone with our salespeople. All of them are also skilled technicians who are very knowledgeable about vacuum cleaners, both inside and out. They will be happy to talk with you regarding your various vacuum cleaner needs, preferences and desires.

Next Vacuum Performance Aspect: Filtration Efficiency HEPA, Micron, etc.

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