One of the greatest strengths of the Honeywell RTH221B (starting at $17, Amazon) is its small size and vertical orientation, which fits into spots that other thermostats don't. Another selling point is its simplicity. Honeywell RTH221 reviews at Home Depot are filled with anecdotes about novice DIYers who nimbly managed installing the device in less than 20 minutes, albeit sometimes with a bit of help from the hardware chain's tech support unit. These purchasers also like the low price, user-friendly programming, and accurate temperature control. Reviews posted at Walmart and Amazon generally echo these comments while emphasizing the value pricing and no-frills simplicity. Some Honeywell RTH221B reviews, however, grouse about the absence of a backlight on the display.
The Honeywell RTH221B differs from the others we researched with its full-week program mode; that is, all seven days adhere to the same four period settings rather than following a 5-day/2-day or an even more variable arrangement. This is a 24-volt model that runs on two AAA batteries and features a low-battery indicator. Users can override the settings on a temporary basis (until the next period kicks in) or more permanently for manual control.
If you need a cheap programmable thermostat that fits in tight places, the Honeywell RTH221B is the model for you. It's easy to install and program and does a fine job maintaining the desired temperature. The very low price and basic functionality should appeal to many consumers.