A while ago, one of you guys asked me to talk about vacuum cleaners and how they relate to their air intake, or better said, suction. It is trivial, vacuum cleaners are built to suck.
A high suction power vacuum cleaner is more effective in getting rid of dirt and grime hidden away in your carpets and tricky corners, in between pieces of furniture, under your bed and so on. A vacuum cleaner with low suction power may get the visible film of dust go away, but it doesn’t necessarily remove the more harmful level of grime underneath. The higher the suction power, the better your chances are of removing difficult impurities from various surfaces. A high suction power vacuum cleaner not necessarily uses a stronger motor. It is all about design here. Let’s elaborate.
What does “high” suction power even mean?
Most people find it difficult to differentiate between low and high suction units. If you want to quickly test the suction power of your vacuum cleaner, try switching the cleaner to “carpet mode.” Power on the unit and let it run on maximum power. Try attaching the floorhead to a wall. If you have high suction power device, it should stay attached to the wall without any external support.
I’m sure many of you want more specific details. That is why we to rely on real measurements. To understand the term “suction power”, you just need to know how it is measured. Suction power may be provided in manufacturer’s specs in several ways, by various units: Watts, Amps, CFM (cubic feet per minute) or AW (Air Watts). Let’s see what each of them means.
It’s one of the most important types of measurements, and it represents the power of the airflow, from the surface to the bag (or bin): it is the quantity of air sucked by the unit in 1 minute, measured in cubic feet (ft3/min). Although it is important, manufacturers don’t always list this measurement. In fact, more than 50% don’t. If you’re lucky and they offer this indicator on the product’s features list, it’s great! This dimension takes into account both the power of the motor and the resistance of the exhaust system (filters, fans, bags, cyclones and so on). The higher the CFM value, the higher the suction power. Common vacuum cleaners operate in the range of 50 to 100 CFM.
Tip: CFM is usually measured without any connected hose, wand or other accessories. That is why it is possible to end up with an actual lower CFM than the one listed in the specs.
Air Watts (AW)
Air Watts are another type of measurement for the suction power. This refers to the amount of Watts used by the machine to carry a unit of air through an opening (usually the vacuum’s nozzle). This is my favorite measurement, because it’s more consistent to the reality of what needs to be quantified. If you know the CFM and the Water Lift (also called sealed suction, measured in inches of water list, when there is a zero nozzle opening), you can calculate the Air Watts size by using the formula:
Air Watts = 0.117254 * Airflow (CFM) * Water lift (inches of H2O)
Hoover once had an article on their website (it’s gone now, I would have linked it), and it said something like this: an efficient upright should have at least 100 AW and a canister, at least 220 AW. Why do you think canisters need more AW? Because they need to pull the debris through the hose. Also, vacuum cleaners with good filtration systems (i.e. HEPA) need more AW, because they need to pull the air through filter’s fibers, which are way tinier than in the case of common sponge filters.
Tip: As you might have guessed, an Air Watt is essentially different from a Watt: 2 vacuum cleaners with the same motor consumption (same number of Watts) may have a very different efficiency (different number of Air Watts).
Water lift (inches of H2O)
The seal suction test is another good way of assessing the suction power of a vacuum cleaner. The unit is completely sealed and connected to a tube which contains water. The higher it raises the water level, the bigger suction it has. However, normal vacuum cleaners don’t deal with this kind of situation (some even have a mechanism that lowers/turns off the power in order to prevent overheating).
This is probably the most common value provided the manufacturer. Watts refer solely to the motor power consumption, not to its performance. As a general rule of thumb, units with higher watts have more powerful motors and thus, suck better. However, this is not always accurate, and there’s is even a public debate running at the moment precisely on this matter. In EU i.e., the law forbids (since 2014) to produce vacuum cleaners that consume more than 1600W. 5 years ago, EU officials were estimating to enforce this law to 500W by 2015, but things have chilled out in the meantime.
The Amps specification is in a way, similar to Watts, as it also refers to power consumption. Thus, the logic listed above stands: the higher the Amps, the better the suction power. However, manufacturers usually provide an Amp value for the entire unit, which includes other electrical systems such as the brushroll or the LED lights. Of course, the biggest electricity consumer remains the motor, but in order to be able to compare 2 units, one measured in Watts and the other measured in Amps, you should know precisely how much these adjacent systems “eat”. As most of you know by now, the maximum amperage of any appliance is 12. Given a 12 Amp unit, knowing the head nozzle consumes around 1.5 Amps and that LEDs draw an additional 0.5 Amps, the real motor amperage should be 10.5. From here, things get pretty easy, because we can use the following formula:
Watts/Volts (120 in US) = Amps
This unit has in fact little to do with vacuum cleaners and their effectiveness. Commonly referred by “Peak Horsepower” in shop-vacs (actually, lots of models produced by the brand Shop-Vac), this measurement shows the in-rush current, measured in the first milliseconds from powering on the unit, which is inflated by the low motor temperature.
Tip: Horsepower is really a bogus and has nothing to do with the actual suction power.
What is the highest suction power of a vacuum cleaner?
Suction power can vary a lot, by a lot of factors, external and internal. While testing, if you run the cleaner without a bag or without its HEPA filter, you will get high levels of suction. To the best of my knowledge, no one really tested suction power unitary. IMO, the Watts/Amps measurements are almost useless. A standard measurement should be AW, but we’ll have to wait a lot to reach that point.
One of the highest measured suction powers in a commercial vacuum cleaner is 200 CFM. Again, this was achieved without the vacuum head: the power drops significantly when we start to attach things. The lowest suction in a standard home vacuum cleaner would be around 45 CFM, but I’ve seen worst.
Do canisters have a higher suction power, compared to uprights?
Canisters or cylinder cleaners and upright vacuum cleaners are the most commonly used types of vacuum cleaners. Among these two, canisters have a much stronger market presence in EU, and uprights are more common in US.
The rule of thumb is, canisters are more powerful than upright models, because they need to compensate the longer reaching distances resulted from connecting the hose and telescopic wand. On the other hand, upright vacuum cleaners have the cleaning head and the brushroll much closer to the bag. The cleaning principle of an upright is based on a sweep-and-vibrate action. The upright model comes with a rotating brushroll or beater bar. While this doesn’t help the suction, it allows you to collect more. The bags/plastic bins are also much bigger with upright vacuum cleaners. As a result, uprights don’t need the same amount of suction as their smaller brothers.
How about shop-vacs or backpack vacuums?
A shop-vac is basically a large bucket type vacuum cleaner that is employed to clean commercial spaces like shops and large storage facilities. It is also known as a wet/dry vacuum. These vacuum cleaners are generally more powerful than your standard home vacuum cleaner and have a higher suction power. They can be used to clear out foliage, sawdust, shavings of wood, and grass clippings among other debris, and can be used over an extensive area. Most shop-vacs are capable of vacuuming up water. That means they need higher suction levels. Many models reach 200 CFM.
Backpack vacuums, on the other hand, are easier to use, and have a very low distance between the air intake and the dirt recipient. Thus, they need less suction power. The last Rubbermaid backpack vacuum I’ve analyzed was averaging 110 CFM and was sucking everything nicely.
How much suction power is enough?
The level of suction power required in a vacuum cleaner depends only on your needs. It’s like buying a car. Smaller motors consume less. Bigger motors are more powerful and fun. If you are looking for a vacuum cleaner to keep your home or small office space clean and free of dust, a standard canister with a moderate level of suction power would be a good choice (you will save energy). If you are looking at heavy cleaning chores such as for an industrial area or a large shop, you will obviously need a powerful unit such as a shop-vac, which can take care of heavy debris effectively, in a shorter time span. If you’re looking for numbers, let’s just say 180-200 AW is great for an upright, 80-100 AW is more than enough for a cordless and 300+ AW should be ok in a canister.
What are the downsides of having a high suction power vacuum cleaner?
Though a vacuum cleaner with high suction power has a number of benefits, it has its cons as well. Due to the fact that it employs a very powerful motor, extensive use can result in higher power consumption. Apart from that, they can be very noisy and cause sound pollution. Last but not least, these units will know a high temperature variation which will wear them faster.
Top 5 vacuum cleaners by suction power
Here are 5 units which really “suck” (I always keep this top updated):