Panasonic's AeroBlast makes some odd noises

Manufacturers regularly add all kinds of features to their vacuums to make them work better—at least that’s their goal. One of Panasonic’s latest wrinkles is the "PowerBlast Automatic Filter Cleaning System," found on the AeroBlast MC-UL975 upright vacuum ($700, shown).

When you turn on the vacuum, a series of belching sounds announces that the vacuum is routing air back through the filter. All the commotion is designed to keep this upright from losing suction.

A video ad for the vacuum says the filter-cleaning feature “not only extends the life of your filter, it helps ensure consistent suction, maximizing your cleaning power and making your job as easy as possible.”

But in our tests, fine dust tended to clog the filter, and airflow through the hose did not match that of our top performers.

This 12-amp, HEPA-filter-equipped vacuum is also an unremarkable cleaner—it did no better than mediocre on carpets and even bare floors, a test aced by most other uprights and canisters in our latest report. Also note that the MC-UL975 is a bagless vacuum. Emptying the bin on a bagless model can be a messy, dusty process, especially a concern if you suffer from allergies.—Ed Perratore

Essential information: Read our March 2008 vacuums report, with Ratings of 61 models. If you're in the market for a new vacuum, watch our video buying guide. And celebrate the 100th anniversary of the vacuum.