The Honeywell RTH8500D 7 Day Touchscreen Programmable Thermostat costs about $110 whereas the Lux Products TX9000TS Touchscreen 7 Day Programmable Thermostat costs about $70. This post will examine the differences between these two popular digital programmable thermostats.

The Honeywell RTH8500D is compatible with a wider variety of HVAC systems than the Lux Products TX9000TS. The later can only manage 1 stage of heating and 1 stage of cooling and single stage heat pumps; whereas, the former can deal with 2 stages of heating and 2 stages of cooling and heat pumps with auxiliary heat. The Honeywell RTH8500D also has the advantage of being able to take its power from the mains.

Both these thermostats are at the higher end of their respective ranges because they offer touchscreen programming. Consumer testing has shown that touchscreens make programming of thermostats easier to understand for the layman and first time user. These two thermostats both have easy to understand programming styles. They also both offer 7 day programming with 4 periods of heating/cooling to set up for each day.

Both thermostats can cycle the fan and both warn the user when to change the filter. The Lux Products TX9000TS has a display which can be changed to show either Celsius or Fahrenheit. The display can also show energy usage. The Honeywell RTH8500D display doesn’t do any of these things but it does have a real time display that makes automatic changes for daylight saving.

In terms of functions both thermostats have temporary hold, adaptive intelligent recovery and auto change-over. The Honeywell RTH8500D has a vacation mode that is missing on the Lux Products TX9000TS.

The major difference in terms of functions between the Honeywell RTH8500D and the Lux Products TX9100E is that the Honeywell device doesn’t have swing control whereas the Lux Products device does. Swing control lets the user set up a range around the set point temperature within which the HVAC is not activated. Honeywell thermostats let the user set the number of cycles instead. In temperate conditions both systems work fine.

If the HVAC is single stage it makes sense to go with the cheaper Lux Products TX9000TS. If the user really wants a vacation mode then the Honeywell RTH8500D is preferable. All things being equal, both thermostats do a great job of improving indoor comfort and reducing heating and cooling bills.