Vacuum Cleaners Buying Guide

This kind of thing takes time to learn, but it is very easy to forget. So I'll take note of it here.

There are eight types of vacuum cleaners in the market: upright, canister (or cylinder), stick (or broom), handheld, robotic, wet/dry, carpet steam, hard surface steam (for the last three types, see Lowe's how-to-buy guide for details). In addition, you can have a central vacuum system (see Cana-Vac Central Vacuum System Buyers Guide).

Among these, the most basic types are upright and canister. The upright type is for carpets while the canister type is for hard surface such as kitchen floors, though some canister cleaners these days can also be used for carpets. Here is the check list for deciding which to buy.

1. Beater
The upright type usually has a beater to loosen and bringing dirt out of the carpet. Some canister types also have it.

2. Bagless (or cyclonic) versus bagged
With bagged cleaners, you need to purchase a new bag from time to time. Check if the cleaner has a "Bag Full" indicator. Bagless cleaners allow you to empty the dust bin without the hassle of changing a bag.

3. Filter
Bagged cleaners do not have filters. Bagless ones come with filters. HEPA filters are ideal for people with allergies. Of course, a better filter raises the price up.

4. Cord length and its retractability (or automatic cable rewind)
Make sure that the cord length is long enough. The canister type usually has automatic cable rewind while the upright type often requires you to wind the cord on your own.

5. Suction power
The number of amps has nothing to do with the suction power. Some companies use the unit called "airwatt" to measure the cleaning efficiency. (Do not confuse it with "watt" for amps.) The higher the airwatt is, the more powerful the cleaner is. A reviewer at Shopping.com says, "suction alone does not make a vacuum clean efficiently, it also requires airflow [(the volume of air a motor is capable of moving)] to pick up dirt."

However, most cleaner-makers only report the number of watts...

References:
Electricshopping.com
eHow.com
eBay Guides