The difference between Hoover UH72400 and UH72450 is:
Hoover UH72400 is lighter and cheaper while the Hoover UH72450 has a larger dust bin and comes with a Turbo Tool for furniture and stairs cleaning.
And there is a Air Valve Dial on UH72450 that can be used to reduce suction power and makes switching between floor modes and tool modes easier by turning the dial. On the UH72400, the hose needs to be moved from one port to another to use the tools.
The comparison table below shows more details:
Hoover Air Steerable vs Pro
| Hoover UH72400 Air™ Steerable Bagless Upright | Hoover UH72450 Air™ Pro Bagless Upright | |
|---|---|---|
 |  |
|
| Design | Upright | Upright |
| Steerable Technology allows you to moves the vacuum around corners and objects smoothly | Yes | Yes |
| Price | $159.99 at Hoover.com on July 22, 2014 | $199.99 at Hoover.com on July 22, 2014 |
| Bagged or Bagless | Bagless | Bagless |
| Dirt Bin Capacity | 1.2 liters | 1.5 liters |
| Bottom-Release Dirt Cup | Yes | Yes |
| Power Source | Corded | Corded |
| Cord Length | 30 ft | 30 ft |
| Auto Cord Rewind | No | No |
| Amps | 11 Amps | 11 Amps |
| Motorized Brushroll | Yes | Yes |
| Brushroll On/Off | Yes | Yes |
| Height Adjustment Type | Self Adjust | Self Adjust |
| AllergenBlock prevent 99% of allergen particles from re-entering the air. | Yes | Yes |
| Washable Filter | Yes | Yes |
| HEPA Filtration | Yes | Yes |
| Headlight | No | No |
| Weight | less than 14 lbs | 14.4 pounds |
| Cyclonic Action | Multi-Cyclonic | Multi-Cyclonic |
| WindTunnel Technology | WindTunnel® 3 Technolog | WindTunnel® 3 Technolog |
| Nozzle Width | 12.5" | 12.5" |
| Handle | Detachable Handle | Detachable Handle |
| Hose Type | stretch hose | stretch hose |
| Self-propelled | No | No |
| Edge Cleaning Brush | No | No |
| Included Tools | Crevice Tool, Dusting Brush | Air Powered Turbo Tool for cleaning furniture and stairs, Crevice Tool, Dusting Brush |
| Cleaning Wand | Yes | Yes |
| Hose Length | 12' | 12' |
| Above Floor Cleaning | up to 14 feet | up to 15 feet |
| Color | Gray | Gray |
| Warranty | 5 year limited warranty | 5 year limited warranty |
| Manual | download uh72400 manual | download uh72450 manual |