I just installed one of these to replace our existing Honeywell t-stat, which was a T8600 series (badged as a “Chronotherm IV Plus”). As part of our big boiler job, we’re splitting our main floor into two heating zones, and I’ll use the old stat for the new zone. The new VisionPro 8000 has a humidity control that will run the A/C when the humidity goes above a preset value. This is the first thermostat I’ve seen with this feature. I’ve always thought it would be a great idea, especially on cool, humid days when the A/C doesn’t run much and the house feels damp and clammy. It doesn’t take much A/C to lower the humidity in the house; just a few minutes to circulate air through the condenser. When you’re trying to change the temperature, you have thermal mass to deal with; that’s not the case with humidity. So, thanks to the new stat, we can have a comfortable house on cool, humid days, without using much extra electricity.
Aside from the humidity control, the VisionPro has a number of improvements over the old Chronotherm IV line. Among others:
- A much more installer-friendly mounting plate. It has holes to fit a standard electrical wall box. Also, the wire entry opening is in the middle, with mounting holes centered on either side of it. The Chronotherm IV’s mounting holes were off-center, making it a pain to put one where there was previously an electrical box (I know this from experience).
- One single model handles multiple powering schemes. The Chronotherm IV had three separate models: A power stealing type, a battery powered model, and a direct-wired version that used a common wire. For the VisionPro, they’ve dropped the power stealing option and included both battery and transformer options on the same model. If both are used, the batteries are used for backup power. To me, this makes sense and I’m sure it reduces manufacturing overhead costs.
Add to that a nice, slick touch-screen interface, and it seems like a great thermostat. We’ll see how it does over time.