How do I choose a vacuum for carpet?
Vacuums often have the option to control the suction power manually. If a floor is covered in carpet, it's a good idea to turn the suction power to maximum. In rugs, the dirt can get quite deep and that's when the extra suction power comes in handy. Do be careful with loose rugs, though. Turn down the suction power quite a bit, so the vacuum doesn't suck up the rug itself. Stick vacuums usually don't offer this option, but they don't need to in most cases.
Carpet brush attachments
There are special brush attachments available to get your floor as clean as possible. As people walk on it, dirt may get deep into the fibers of the carpet, particularly if you have high-pile carpet. In that case, it can be difficult to clean the carpet with a canister or stick vacuum. Have pets walking around shedding hairs everywhere? In that case, the right brush attachment might be even more important.
For most low-pile carpets or rugs, a multi-surface brush will generally be sufficient. When vacuuming a carpet or rug with this brush, you can manually set the brush to carpet mode. Adjust the brush again if you have hard flooring as well as carpet. Convenient, since you won't have to change attachments.
If you have a high-pile carpet or coarse carpet, you'll need a turbo brush. Turbo brushes often have harder bristles that get deeper between the fibers of the carpet or rug to remove more stubborn dirt as well. A turbo brush is also recommended for coarser, low-pile to vacuum any deeper-lying dirt.