Understanding Vacuum Cleaner Specifications

Understanding a large variety of confusing				makers, as well as some other vacuum cleaner
specifications is one of the most challenging				manufacturers, have been using the air watts
aspects of selecting a new vacuum cleaner. First				specification to attempt to rate the vacuum
and foremost, consumers want vacuum cleaners				cleaner's output rather than input power. Air
that offer the best cleaning ability. And most				watts are calculated using the formula, (Air Flow
consumers typically equate cleaning ability with				(in CFM) x Vacuum (in inches of water lift))/8.5 =
"power" or "suction".				Air Watts.
Cleaning ability is not just about power and				Once again, there is some question as to whether
suction, even though these attributes are				this is a useful specification or just a new rating to
important elements of vacuum cleaner				further confuse consumers and make
performance. With a little information and				comparisons difficult. After all, when you do the
education, you will be able to sift through the				calculations, an air watt comes to 0.9983 watt or
numbers and better understand what the				just about the same as an ordinary watt.
specifications mean and which ones are important				It is important not to confuse air watts with
to you.				airflow, the most important specification of all.
Unfortunately, there is no single rating that				Airflow
indicates cleaning ability. However, there are a				Airflow is by far the most important specification
number of primary specifications, that when				in terms of determining the cleaning ability of a
clearly understood, allow consumers to make				vacuum cleaner. Measured in cubic feet per
educated decisions concerning which vacuum				minute (CFM), it is the force of this airflow across
cleaner will have the best cleaning ability.				a surface that picks up the dirt and moves it to
These primary specifications include watts, amps,				the dust bag or container. Therefore, the more
volts, water lift (or sealed suction), horsepower,				airflow, the better the cleaning ability of the
air watts, and airflow.				vacuum cleaner.
There are also a number of other, secondary				Airflow is an excellent specification because it
specifications that influence cleaning ability that				takes into account both the power of the
we'll also examine. These include filtration, cleaning				vacuum motor, which creates suction, as well as
tools (agitation), capacity, quality, noise, features				the resistance of the bag and filter system that
and cost.				this air must pass through.
In order to make sense of all this we first need				Airflow is generally measured through the vacuum
to understand the basics of how a vacuum				cleaner without hose or attachments connected.
cleaner works.				Because of this, there are several factors that
All vacuum cleaners operate based on air flowing				can affect actual airflow, including turbulence in the
from the opening at the cleaning head or tool,				hose and wands, restrictions on airflow where the
through the vacuum cleaner and the bag and/or				cleaning tool meets the floor or other surface,
filter system and then out the exhaust port. This				increased resistance due to the bag filling with dirt,
airflow is created by the vacuum motor, which				as well as filter loading.
also may be referred to as the suction motor.				Comparing Primary Specifications
The vacuum motor consists of electrical				In terms of these primary specifications, there
components attached to a fan or multiple fans.				are three elements that are useful in comparing
When the fans spin, a partial vacuum is created				vacuum cleaners.
and the pressure inside the vacuum cleaner drops				The first comparison is watts to watts motor
below the ambient (or existing) air pressure in the				input power. Ideally, the machines being compared
room. Because air pressure is higher outside the				will all have motor input power specified in watts
vacuum cleaner than inside, air rushes through the				for a simple, direct comparison. If one machine is
vacuum cleaner.				rated in amps and the other in watts, a
So, it is easy to see that the vacuum motor is				conversion of the amps specification to watts
the heart of a vacuum cleaner. After all, the more				makes comparison possible but is "apples to
powerful the motor, the greater the pressure				apples" only if the motor amps alone are used for
differential and therefore the more suction and				this comparison.
airflow, right? And it is for this reason that most				As mentioned in the amps section above, if the
of the specifications you see concerning cleaning				only specification available is the amps for the
ability relate either directly or indirectly to the				whole machine, a comparison can still be made but
motor.				it will not be a direct one.
But here's where it gets tricky. Specifications for				If both machines are rated only in amps, a
components such as the motor do not necessarily				comparison can be made of the electrical
relate to the performance of the entire vacuum				consumption of each unit with an assumption that
cleaner, and therefore are only a part of the				if these are close or equal, the motors are similar
story.				in input power. This is because the motor will be
Let's take a look at the primary specifications one				the biggest consumer of the rated amperage.
by one:				The second comparison will be water lift (sealed
Watts				suction). This is a good specification to compare
The input power of the vacuum motor is				how well the vacuum cleaner will perform as the
measured in watts. Although this specification				bag fills and the filters load, and is especially
doesn't take into account the efficiency of the				relevant when choosing high filtration or HEPA
motor, the number of fans or the overall vacuum				filtration vacuum cleaners. It also provides some
cleaner design, motor wattage is a valid way to				idea of how vacuum cleaners compare in terms
evaluate and compare the power of the motor.				of picking up heavier soils such as sand, grit and
While the ideal comparison is motor input power in				so on.
watts of Product A compared to motor input				The third point of comparison is airflow. This is the
power in watts of Product B, some				most important specification of all when choosing
manufacturers do not provide motor input power				a vacuum cleaner because airflow is what moves
specifications in the form of watts but instead				the dirt from surfaces to the dust bag or
rate the entire vacuum cleaner in amps. This can				container. In short, airflow is the best specification
make it hard to compare across brands.				that demonstrates cleaning ability.
However, you can convert amps to watts by the				So, now with airflow rated in CFM and water lift
formula, amps x 120 (volts) = watts. Or				rated in inches, what types of numbers should
conversely, you can convert watts to amps by				you be looking for? On canister vacuum cleaners
the formula, watts/volts (always 120) = amps.				(with or without power heads) airflow of 100 CFM
For example, a 1400-watt motor converts to				or more and water lift of 90 inches or more is
11.67 amps (1400/120=11.67).				recommended.
Comparing machines rated in amps with those				Upright vacuum cleaners come in a wide variety
rated in watts is not an exact comparison				of configurations, but there are two basic designs.
because manufacturers that are using watt				The first is the "Direct Air" or "Dirty Air" design
ratings typically rate the motor only while				where the dirt passes through the motor prior to
amperage ratings use the total electrical				any filtration en route to the dust bag. Dirty air
consumption of the vacuum cleaner including the				uprights are only rated in amps.
motor in the power nozzle (the motorized				The second basic design is one that features a
revolving brush cleaning head), light bulb, etc.				by-pass motor where unfiltered air does not go
This means that a Power Team (a canister				through the motor. In uprights with this design,
vacuum cleaner with a power nozzle) with a				only filtered or completely clean room air passes
specification of 12 amps might be quite				through the motor in order to cool it. By-pass
comparable to another Power Team with a				uprights will usually provide airflow but not water
1200-watt motor that converts to only 10 amps.				lift specifications and a high performing upright will
This is because the power nozzle motor				offer 60 CFM or better.
consumes 1.5 amps, the bulb uses additional				There is no need for water lift ratings on both
amperage and so on. So, if we subtract the				types of uprights, because there is so little
amperage used by the power nozzle motor from				distance for the air and soil to travel. CFM ratings
our 12 amp machine, we come up with 10.5 amps				do not have to be as high as canisters for the
for the motor and light bulb. In this example, the				same reason.
two motors both have ratings of very close to				Many uprights will not offer airflow ratings at all
10 amps, and therefore, equivalent motor input				and will only rate the motor in terms of amps. As
power.				we have learned, this only measures the electrical
Therefore, it is best to either compare motor				consumption of the motor, which is not a
input power in watts of both machines or if you				measure of cleaning ability. Still, when comparing
have to compare a machine rated in watts with				different vacuum cleaners of this type, amp
one rated in amps, try to get the amperage				ratings are better than nothing.
rating of the motor only instead of the entire				When you choose a vacuum cleaner with
vacuum cleaner. You can then convert this to				excellent airflow and water lift specifications, you
watts and have a meaningful comparison.				are well on your way to a machine with
Amps				outstanding cleaning ability.
A very common vacuum cleaner specification is				Secondary Specifications
amps. The amperage rating designates the				We have examined the primary specifications that
maximum amount of electrical current used by all				impact cleaning ability. But there are also
of the vacuum cleaner's electrical components				secondary specifications that should be considered
when operating. The biggest consumer of				before making a final decision. These include
electrical current will be the vacuum motor, but				filtration, cleaning tools (agitation), capacity, quality,
the amperage rating includes all of the electrical				noise, features and cost.
components, including the vacuum motor, the				Filtration
power nozzle motor, the light bulb, etc.				Filtration is very important in terms of cleaning
The maximum amp "draw," (the number of amps				ability because HEPA or other advanced filtration
the vacuum cleaner uses when running) allowed				increases the resistance within the vacuum
for any appliance that plugs into a standard				cleaner. Therefore, it is easier for a vacuum
household outlet is 12. Therefore, if you see				cleaner with normal filtration to accomplish higher
amperage ratings above 12, read the fine print, as				airflow ratings. In fact, the challenge of coping with
they are not true amperage specifications but				higher resistance is one of the reasons that HEPA
some other manufacturer developed				filtration vacuum cleaners can cost more.
"performance rating" designed to create the				For more information on HEPA filtration vacuum
impression of a more powerful vacuum cleaner.				cleaners, click here.
Although amperage refers to electricity				The dust bag is also part of the filtration system
consumption and not power or cleaning ability per				and a significant factor influencing airflow. Many
se, it can be used to compare the input power of				new materials, as opposed to traditional paper,
one vacuum cleaner to another. This is because				are being used to manufacture dust bags in order
while input power is measured in watts, amps are				to retain the fine dirt and harmful small particles
converted into watts by multiplying by volts. Since				while still allowing air to flow as freely as possible.
volts are constant at 120, amps represent a valid				The surface area of the dust bag is also a factor
comparison of motor input power.				because the more surface area the bag has, the
Again, as mentioned above, when making this				more easily the air will flow through it. This
comparison, try to get the amp rating of the				translates to better cleaning ability as the bag fills.
motor only instead of the entire machine.				This is a good reason to choose full sized vacuum
Therefore, amp ratings give us a means of				cleaners versus medium or compact ones.
comparing the input power of a vacuum motor				Cleaning Tools (Agitation)
and the vacuum cleaner as a whole and are a				The primary cleaning tool must be correctly
meaningful specification for comparison purposes.				selected because while airflow is what transports
But again, they are only part of the story. After				those soils to the dust bag, agitation is what
all, just because a motor or vacuum cleaner				dislodges soil from carpeting, flooring and other
consumes more electricity, this does not make it				surfaces.
a better cleaner.				Therefore, explore the type of cleaning tools that
The amps specification also does not take into				make sense for your home. If you have lots of
account how efficient the motor is, as well as				carpet or difficult soils such as pet hair, choose an
other design factors, such as whether the motor				upright or a power team with a motorized power
has one or two fans (two is not necessarily				nozzle. If you have furniture that is difficult to get
better than one) and the overall efficiency of the				under, be sure your vacuum cleaner has a low
vacuum cleaner design.				enough profile cleaning nozzle to reach these
Voltage				areas and so on.
In the United States, standard household current				If you have a vacuum cleaner with all the airflow
operates at 120 volts at the meter. Voltage within				in the world but an inadequate cleaning tool,
a home is sometimes referred to as "110" and				results will be less than optimal.
this is because there may be voltage drops				Capacity
through the house wiring. But not to worry,				The capacity of your vacuum cleaner has a role
appliances are designed to operate within a range				in terms of maintaining high levels of cleaning
of voltages from 110 to 120.				ability. As we saw above, the larger the dust bag,
For the purposes of understanding vacuum				the better the airflow, and therefore, cleaning
cleaner specifications the only thing about voltage				ability. All other things being equal, a full-sized
we really need to know is the formula, amps x				vacuum cleaner will offer better cleaning ability,
volts = watts and conversely, watts/volts =				especially as the dust bag or container fills.
amps. When doing these calculations use 120 volts				Quality
for U.S. appliances.				The quality of your vacuum cleaner is also
Water Lift (Sealed Suction)				important. You can have excellent specifications in
The sealed suction of a vacuum cleaner is				a poorly constructed vacuum cleaner that will last
measured in inches of water lift. This rating is				only a few years, compared to extremely high
taken when the motor is totally sealed, and the				quality products that will deliver outstanding
term refers to how many inches the motor will				cleaning performance and will last many years and
vertically lift a 1" column of water.				even decades.
Water lift is what gives a vacuum cleaner the				Quality can be partially determined by the length
power to pick up or "lift" debris from the floor				of the warranty as well as the type of materials
surface, while airflow then removes it to the dust				used, the quality of the fit and finish, how heavy
bag. Vacuum cleaners with more inches of water				duty the housings are, how tight the seals, how
lift will have an easier time picking up sand and				close the tolerances and so on. Generally,
other heavier soils from carpet and flooring.				mass-market, low-priced products are not
Water lift is also a measure of a vacuum cleaner's				designed for long-term use.
ability to deal with resistance within the vacuum				Noise
cleaner. This is especially important in HEPA or high				Noise is also a significant consideration. Some
filtration vacuum cleaners that have more				vacuum cleaners can be so noisy that they're
resistance due to the additional filters that the air				almost unbearable to use. A high-quality vacuum
has to pass through.				cleaner will often operate at levels that are quite
A good water lift rating also indicates that a				comfortable and will allow you to hear the phone
vacuum cleaner will keep performing at high levels				or doorbell ring quite easily.
as the dust bag or container fills and the filters				The amount of noise a vacuum makes while
"load" or gradually fill with fine particulate and				operating is rated in decibels (dB). To give you
become more and more resistant to air passing				some idea, a conversation at home is rated at
through.				50dB, a garbage disposal at 80 dB and a
The water lift of a vacuum cleaner is another				motorcycle or lawnmower at 100 dB. Extremely
useful indicator of performance in that it is a				quiet vacuum cleaners can operate at decibel
means of comparing the suction of one motor to				levels in the mid-sixties while cleaners in the 70-77
another and, generally speaking, the more water				dB range are still very quiet compared to the
lift the better.				vacuum cleaner you grew up with.
Horsepower				Features
This is a rating that was used primarily for				Next, you need to consider whether the vacuum
marketing purposes and had little or no relation to				cleaner you're considering has all or most of the
vacuum cleaner performance in the real world.				features that you need for effective and pleasant
Thankfully, it has been largely done away with as				cleaning.
a vacuum cleaner specification.				Consider your cleaning situation and be sure that
Often referred to as "Peak Horsepower" these				the vacuum cleaner you choose gives you
ratings were obtained by removing the fans from				everything to make the chore of vacuuming as
the vacuum motor and subjecting it to the				easy as possible. Does it feature a cord rewind,
maximum load possible before the motor burned				variable speed controls, on-board tool storage,
out. Then, a complex formula was applied to				height adjustable wands, an adequate cleaning
come up with a Peak Horsepower rating. Again,				radius, the proper tools for your flooring such as
this specification is meaningless in terms of				a soft brush for your slate entry tiles and so on.
evaluating the cleaning ability of a vacuum cleaner.				Cost
Air Watts				And, last but not least, you need a vacuum
As we have discussed, typical vacuum power				cleaner that represents the very best value. As
specifications such as watts and amps measure				with everything, better quality usually costs a bit
the vacuum cleaner's input power. Central vacuum				more, but is often worth it in the long run.

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Understanding Vacuum Cleaner Specifications