Bagged Vacuums vs. Bagless Vacuums  

Bagged Vacuums

Carpet cleaning evolved from rudimentary rug beating in ancient times to mechanical sweepers in the 1850s, once it became apparent that sweeping carpets with a broom doesn't work well to lift embedded debris. A few unsuccessful devices appeared later that used air to blow dust out of carpets, but in 1901, British engineer Hubert Cecil Booth reversed this airflow and developed the world's first suction-based vacuum cleaner. The idea seems simple to us now: blow air out of a sealed canister (creating a vacuum), and let air in through the vacuum hose. Fit a bag over the end of the vacuum hose inside the canister, and the bag catches the dust, acting as a filter to keep dust out of the exhaust air and out of the blower motor. Simple.

Your first experience with vacuums was probably with a bagged vacuum, and you might've experienced the downsides of older bagged vacuums. Expensive bags filled to the brim with months or even a year's worth of household dust and hair. Pulling the soiled dirtbag out of the vacuum and trying to put it in a garbage bag without releasing all this crud into your face. Trying to find a new bag, realizing you have none available, and trying to buy a new compatible one. Finding that they haven't made bags like this in years, or finding that your vacuum has one letter in the model name different from the compatibility tables of bags you can find.

With bagged vacuums, the bag fills with dust the more you vacuum, which clogs the pores and channels of the bag material, thereby restricting air flow. This might increase filtering performance at first, but eventually the motor struggles more and more to move air, consuming more power and running hotter, and the cleaning effectiveness drops as the airflow drops. You have to change the dirtbag at a certain point, because if you don't, you run the risk of the bag bursting. If the bag bursts, you'll have a big mess to clean up, not only inside the vacuum but all over your house, since all this dust will get blown right out of the exhaust. You could also permanently damage your motor if you get too much dust in it, effectively destroying the vacuum.

Every manufacturer has their own dirtbag design, and sometimes every model has its own design. So finding compatible dirtbags for an older vacuum might be quite hard. And you can't operate a bagged vacuum without a bag, so you have to have them on hand. If you can't find a replacement bag, the vacuum is useless.

But most of those drawbacks were with old bagged vacuums, and bagged vacuums have changed. Plus, on the positive side, vacuum bags can hold a lot of material, and you can fill a bag over many months, so you don't have to empty it frequently.

Air Quality When Operating A Bagged Vacuum

The bag itself is an important part of a bagged vacuum's filter system, so filtering performance is highly dependent on the bag material the manufacturer uses. Originally, bagged vacuums had cloth bag filters, then paper bag filters. Filtering performance was generally quite poor. Now, you're more likely to find nonwoven polymer fabric bags. Some bagged vacuums claim HEPA certification, a standard where the filter removes 99.97% of particles 0.3 µm in diameter or larger. These vacuums usually include good pre- and post-motor filters in addition to the bag. We found that if a vacuum doesn't claim HEPA certification, it's not very effective at containing fine material. Take the Eureka Mighty Mite, for example.

This is an awful result if you care about air quality. This vacuum relies entirely on a poorly constructed bag as a filter and doesn't have a pre- or post-motor filter, so most of the fine dust passes right through the bag and out of the exhaust.

Since nonwoven polymer fabric is an engineered material manufactured to exact specifications, manufacturers can control porosity very well. They can construct a filter bag that filters fine particles quite effectively in combination with pre- and post-motor filters, even meeting HEPA-level filtering requirements. See the Kenmore Intuition Bagged.

This result shows virtually non-detectable levels of dust. This level of performance will be a welcome relief for allergy sufferers, and we can definitely say that this vacuum meets the HEPA standard. We have yet to encounter a HEPA-certified vacuum that scores poorly in this test.

Air Quality When Emptying A Bagged Vacuum

Emptying a bagged vacuum is quite simple: you open the canister, lift the bag out from its retaining bracket, and throw away the bag. The worst-case scenario for air quality is a bag with a wide-open inlet hole, where you disturb the bag and expel a puff of dust-laden air out of the hole as you lift it from the canister. But even the worst bags, like the Eureka Mighty Mite bags, have inlet seals.

SEBO uses a more sophisticated design with the bags for the SEBO Airbelt D4, which have a hinged plastic flap that you fold back to press a tight-fitting plug in the inlet.

These bags only release a small amount of dust when you disturb them by lifting them out of the canister and closing the bag seal.

Miele goes even further for the Complete C3 and uses bags with a spring-loaded cover that snaps shut when they're removed. The vacuum's bag mounting bracket forces it open, so that it shuts automatically as soon as you pull the bag from its mount.

This bag design releases even less dust when you empty it, just a tiny amount that escapes around the bag sealing bracket.

To summarize, below are the pros and cons of bagged vacuums.

Bagged Vacuums: Pros and Cons

Pros

• Infrequent emptying, often many months between emptying
• In combination with good pre- and post-motor filters, bags can filter very well, even up to HEPA standards
• Emptying doesn't release much dust, even with a poor bag design

Cons

• Need to buy compatible bags
• Inadequate bag design can lead to poor filtration and a lot of dust in the air when you vacuum

Bagless Vacuums

A bagless vacuum is just that: a vacuum that filters without a bag. Although bagless vacuums first appeared in the 1930s, inventor James Dyson commercialized the bagless vacuum in the 1980s, based on an old industrial technology known as a cyclone separator. This well-established device uses a blower to push in fast-moving air on the side of a cylindrical chamber. The air hits the side of the chamber and starts to spin like a cyclone or tornado. Any solid particles in this air stream get flung outward, hitting the sides of the chamber, and slow down due to friction. Eventually, gravity takes over, and these solid particles drop towards the bottom of the chamber, collecting in a conical hopper. The air, now free of dust and still spinning, bounces off the conical walls of the hopper, and the spinning air stream forms a narrow vortex spinning up the center of the chamber. It goes up and out of the exhaust on the top.

To fit this in a household vacuum, the cyclone separator needed to be miniaturized, but a single small cyclone separator doesn't create the degree of separation required for effective filtering. So James Dyson used many small cyclones operating in parallel. 

This separation is based on the difference between the mass of the dirt particles and the air, so cyclonic separation works well for heavy particles but not so well for light particles. Because of this, bagless vacuums use conventional post-motor filters to filter out light particles like PM10 and PM2.5 particles. These particles are around 10 µm and 2.5 µm in diameter.

Therefore, the best bagless vacuums use a conventional post-motor filter to keep fine particles out of the exhaust. Some bagless vacuums use a pre-motor filter as well to keep dust out of the motor. Note that these filters must be replaced regularly in some bagless vacuums (like the Miele Boost CX1), so although you won't have to buy bags, you'll have to buy filters. If you have to replace these filters, the recurring cost won't be zero, as it is with bagless vacuums with permanent filters.

The cyclone filters take up space in the dirt compartment, leaving less room for dirt collection, so bagless vacuum dirt capacities are lower than in bagged vacuums. This is especially true for smaller vacuums like Dyson handheld stick models.

Most bagless vacuums have clear dirt compartments so you can see the dirt compartment's fill level and know when to empty it.

Air Quality When Operating A Bagless Vacuum

Without a pre- or post-motor filter, a bagless vacuum does a very poor job filtering out fine particles, as shown with the Shark UltraCyclone Pet Pro+.

This vacuum's filter doesn't really hold back any fine particles at all and expels them right out into the air.

When the manufacturer installs a well-performing post-motor HEPA filter, this problem is eliminated. Dyson has excellent post-motor HEPA filters, and it shows; see the Dyson V15 Detect.

Air Quality When Emptying A Bagless Vacuum

The dust and debris a bagless vacuum collects fall into a compartment. This compartment usually has a flap you can open to empty the vacuum. When you activate the flap trigger, the flap falls open, and the dust falls out of the compartment. This whole activity usually takes place in the open air above a container, so the light dust catches the air as it falls, floating out and bouncing off the walls of the receptacle. You could open the flap while the dirt compartment is entirely in a garbage bag, but it'll still be difficult to contain all this fine dust. These particles are tiny and extremely light. They float up and linger in the air for quite some time. Eventually, they settle back down all over your room.

Emptying the Dyson V15 Detect.

The only way a manufacturer can offer clean, hygienic emptying of a bagless vacuum is by supplying it with a self-emptying dock that empties the dirt compartment into a dirtbag similar to a bagged vacuum's dirtbag. Docks like these are very rare. Notably, Dyson doesn't offer such a dock, but Samsung does, in their Bespoke AI Jet Ultra and as an optional 'Cleaning Station' with their Jet 75 and Jet 90 Complete models.

Emptying the Samsung Bespoke AI Jet Ultra.

You can see only a few motes of dust when our tester moves the dirtbag to the garbage bin. This dust release is even less pronounced than it is when you dispose of Miele's self-sealing dirtbags.

All in all, these are the pros and cons if you're considering a bagless vacuum:

Bagless Vacuums: Pros and Cons

Pros

• Zero recurring cost unless you need to replace filters
• Clear indication of dirt compartment fill level
• Convenient, no bags required

Cons

• Frequent emptying due to the small dirt compartment
• Air quality during operation depends heavily on the post-motor filter
• Messy emptying unless you have a self-emptying docking station

Conclusion

As far as air quality goes, bagged vacuums have the most advantages. Even if you have a model that does a poor job filtering particles during operation, emptying a bagged vacuum is always cleaner than emptying a bagless vacuum without a self-cleaning dock. Your best assurance of excellent air quality is a HEPA-rated bagged vacuum. The choice is yours, and our air quality tests will help you make your decision.

If air quality isn't a concern, our testing shows that performance depends more on floorhead design than whether a vacuum is bagged or bagless, so you should consider other factors.

We always value your feedback! If you have any questions, please let us know in the comments or at feedback@rtings.com. If you have suggestions about how we can improve our testing, we'd love to hear from you. We're constantly making improvements based on your suggestions.