Should I buy a bagged or a bagless vacuum cleaner?

The two designs solve the same problem in opposite orders. A bagged machine makes the bag do the filtering, so the dust arrives already contained and the machine's own filters stay comparatively clean. A bagless machine spins the heavy dust out into a bin and sends everything the cyclone could not catch — which is the finest fraction, and the fraction that matters for allergies — straight on to the filter. That single difference explains almost every practical consequence of the choice.

What you'll need

• A note of who in the house reacts to dust
• Prices for bags and filters for the models you are considering (optional)

Step by step

1. Decide the allergy question first, because it settles most cases.Emptying a bagless bin releases a visible puff of the finest dust into the room, usually at chest height. For an allergy or asthma household that is the wrong end of the machine to make convenient. Bagged, emptied outside at a wheelie bin, avoids it entirely.
2. Work out whether you will actually buy consumables.Bags are cheap and completely useless if there are none in the house. Plenty of bagged machines end up run past full because the last bag was used months ago, which is bad for suction and bad for the motor.
3. Understand how each one loses suction.A bag clogs gradually as its pores fill with fine dust, so suction fades steadily and is often noticeably down at half full. A bagless machine holds suction better between emptyings but drops off sharply once the pre-motor filter loads, which happens far faster than most people expect.
4. Compare the maintenance you will actually do.Bagged: change the bag, and change a filter once or twice a year. Bagless: empty the bin often, wash the pre-motor filter every one to three months and let it dry a full 24 hours, and periodically clean the cyclone cones with a soft brush.
5. Price five years of consumables for the specific model.Bags for a common model are usually modest; for an unusual one they can be surprising. Bagless filters are not free either, and they do eventually need replacing rather than washing. Do the sum before deciding on cost grounds.
6. Look at capacity honestly.Bagged capacity is usually larger in litres but the useful fraction is smaller, because performance falls before the bag is full. Bagless bins are smaller and are emptied at a genuine full. In practice a large house tends to favour bagged.
7. Check the sealed-system claim rather than the filter grade.A HEPA filter in a machine that leaks around its joints does not deliver HEPA-grade air at the exhaust. The phrase to look for is a fully sealed system. This applies to both designs and matters more than which one you chose.
8. Decide, then commit to the maintenance that design needs.Both work well maintained. The failure mode of a bagged machine is running it past full; the failure mode of a bagless one is never washing the filter. Whichever you buy, that is the habit to build.

Tips

• If you go bagless, buy a second pre-motor filter with the machine. Filters need 24 hours to dry after washing, and a spare means you never refit a damp one.
• If you go bagged, keep the spare bags with the vacuum rather than in a cupboard elsewhere. It is the single reason people run them past full.
• Empty a bagless bin outside, or hold it deep inside the wheelie bin before releasing the catch. It keeps most of the dust cloud out of the house.
• Self-sealing bags are worth the small premium in an allergy household, because they close as you withdraw them.

Common mistakes

• Assuming bagless means no filters to buy — The filters take the load the bag used to take. They need washing far more often and still need periodic replacement, so the saving over bags is smaller than it looks.
• Judging a bagged machine by how full the bag looks — Suction depends on the bag's pores, not its volume. A bag that looks half full of fluffy dust can already be badly restricted.
• Emptying a bagless bin indoors over a kitchen bin — The fine dust released is exactly the fraction the machine was collecting to keep out of the air, and it settles back onto the floor you just cleaned.

Alternatives

• Bagged cylinder or upright: Dust sealed at the point of collection, cleaner emptying, and generally the better choice for allergies and for large carpeted houses.
• Bagless cyclonic: No consumable to remember, clear bin so you can see what is happening, and better suction retention between emptyings — at the cost of frequent filter washing.
• Bagged with a self-sealing bag: The version worth paying a little more for if dust exposure is the reason you chose bagged in the first place.

Questions people ask