RCHTSENSOR-1PK, Smart Room Sensor works with T9/T10 WIFI Smart Thermostats

I was skeptical this would actually valance the air in my new home. One bedroom was reading 70 degrees with the thermostat set on 74. Installed these sensors and what a difference. That rooms stays cooler now and the ac doesn’t seem to be running more- it seems to running less.

Must have for a T9/T10 thermostat! Works very well with Home Assistant with local control over HomeKit. Each remote sensor is a separate addressable device with temperature, humidity, and occupancy entities.

items works great, new in box.

I have two ducted Mitsubishi inverter heat pump systems using MHK2 sometimes also known as MRCH2 thermostats. The upstairs system had the thermostat located in a poor location especially in winter. It resulted in the two bedrooms upstairs being about five degrees colder than the set point. I didn't want to put the thermostat intself in a bedroom but I needed to have a temperature sensor in one of them to read the temperature there. I temporarily moved the MHK2 to one of the bedrooms (it is wireless so easy enough to do) and confirmed that reading the temp in one of the bedrooms would get me to where I wanted to be.A few Google searches found some reddit threads that confirmed this sensor would work with the MHK2 even though it isn't listed as compatible. I ordered one from Amazon and can confirm it worked great. Download the MHK2 instructions on pairing this and setting it up (it is wireless). You basically need to sync it with the Redlink controller on your unit (which thankfully does NOT unsync the MHK2). Once synced you need to got into the MHK2 setup menu and select using this sensor (you can either use this remote sensor only--what I am doing, or an average of this sensor and the MHK2 sensor).

No fault of the seller but it seems there are some sensors that are not compatible with the newer T-9 thermostats but are still compatible with the T-10 thermostats. I just got of the phone with Honeywell customer support and they told me to return these and orchard purchase thru the Resideo manufacturer website so that I can request to purchase a compatible sensor based on the model number of my T-9 thermostat.

I got this to work with the Honeywell T9 thermostat, as a second sensor. The T9 averages between the two sensors, and I can set priority between the two sensors and the main thermostat. So far it’s working well to provide more even heat with less temperature swings. I’m considering buying more, but wish they were a little less expensive.I’m worried that these will stop working, based on reviews, but so far so good.

Beware this product is not compatible with T9 or T10 thermostats, just had to return three sensors. Not only were they not compatible I bought them "new" but they were open box AND they could not be factory reset. Factory reset is supposed to occur after 15-30 seconds of holding the connect button. Even after a minute of holding these devices would not reset, I think they must be part of a bad batch or something. Avoid buying these on amazon, the sale is not worth the hassle of having to return.

Easy to setup, and allows me to better control the temperature in a room far from my thermostat.