I used a Honeywell VisionPro IAQ 7 day programmable on my split system heat pump with propane backup. This T-stat solved numerous problems for me. I installed the outside temp sensor, get rid of the mechanical temp sensor most times mounted on outside unit. It permits me to adjust my outside temp cutoff and also lets me monitor the outside temp on the T-stat. Allows control of humidifier, air cleaner and more. A great all in one thermostat.
VisionPRO IAQ | 7-Day Programmable Thermostat Comfort System
All-In-One Control - Controls temperature and Indoor Air Quality (IAQ) products such as humidification, dehumidification, ventilation, and air filtration monitoring - all from a single control in the living space
All-In-One Control - Controls temperature and Indoor Air Quality (IAQ) products such as humidification, dehumidification, ventilation, and air filtration monitoring - all from a single control in the living space
7-Day Programming - Allows separate programming for each day
Touchscreen Interaction - Easy-to-follow menu-driven operation simplifies programming by responding to your choices
Smart Change/Check Reminders - Let you know when to service or replace filters, UV bulbs (based on actual usage) and humidifier pads
Energy Savings - Program to save up to 33% on annual heating and cooling costs (If used as directed. Savings may vary depending on geographic region and usage)
Whole-House Telephone Access - Works with your existing telephone line to offer control of your home's temperature and Indoor Air Quality over the phone
Model Numbers - YTH9421C1010, YTH9421C1002, TH9421C1004
5-Year Warranty