| Feature | 33CS400-01 | 33CS420-01 | 33CS450-01 |
| EL backlight display | x | x | x |
| Keys & legend backlighting | x | x | x |
| Switchable manual or auto changeover | x | x | x |
| Switchable programmable or non-programmable | | x | x |
| Non-programmable | x | | |
| 7 day programmable | | x | x |
| Light activated occupied period (defeatable) | | | x |
| 3 occupied, 1 unoccupied periods | | x | x |
| 2 stage heat, 2 stage cool | x | | |
| 3 stage heat, 2 stage cool | | x | x |
| Adjustable timers/deadbands | | x | x |
| Extra 6th & 7th output | | x | x |
| Programmable output | | | x |
| Economizer control | | | x |
| Outdoor sensor ready | x | x | x |
| Hi/Lo outdoor temp for the day | | x | x |
| Control to, or, monitor 2nd sensor | x | | x |
| Wired remote averaging | | | x |
| Accepts Humidity Module | x | x | x |
| Dehumidification terminal available | x | x | x |
| Reheat capable | | | x |
| Security Levels (set point limiting, etc.) | x | x | x |
| Accepts IR receiver | x | x | x |
| Accepts plug-in programmer | x | x | x |
| Smart recovery | | x | x |
| Dry contact equipped¿ | x | | x |
| UV service indicator | x | x | x |
| Filter alert ready¿ | x | | x |
| Drain pan clog alarm ready¿ | x | | x |
| Aux heat indicator | x | x | x |
| Pre-occupancy fan purge | | | x |
| Smart fan | x | x | x |
| Vacation/Holiday mode | | x | x |
| Energy watch | | | x |
| Random start | x | x | x |
| F or C | x | x | x |
| Overide counter | x | x | x |
A Member of The United Technologies Corporation Family