There actually is a battery inside, I took mine apart, gingerly of course, and it should read 3 volts. Mine was reading 3.4, and it can be done!

Just installed one of these. Super easy.

They do make a version for air conditioning and heating which includes an off switch on the base plate. I understand what you’re saying about the simplicity but the funniest thing is that this thermostat actually does have a battery inside. It’s permanently sealed inside the thermostat and a cr2032 I believe. They say it should last a lifetime but when it eventually does go out you need a new thermostat. Honeywell does make another model that is square and does not have a room temperature read out. That one is truly mechanical with no battery and still mercury free.

Thank you good video

I'm having the same problem with my thermostat it stays at 72 the rest of my house will go down to 66 it still won't kick on until I turn it up to 72% I don't want my house 72 I would like to have it at 70 how do I correct this

Just curious about the recent quality of CT87K1004 compared to the vintage Honeywell T87F Thermostat (similar look, also round shape and no battery required). Can anyone comment on this? Thanks!

thank you

I have one of these in my apartment when I lower it it stays at 70. Should I tell the landlord it’s broken???

Does the furnance need to be off at the breaker or on the furnance when you connect the thermostat? Also, how long would it take for the heat to start coming on?

How do I turn it off ?

Don't be fooled! The Honeywell model I bought, was NOT battery free...CT87K1004. 24 volt Purchased January 2024. It WILL NOT tell you ANYWHERE in the instructions that there IS an internal lithium battery. I had to call their 800 number to find this out! That's when they told me that it takes 20 minutes to charge the internal battery upon installation. This was WHY the thermostat did not work right away.

great, but how does one reset factory temperature, it's wrong by 8 degrees. Example if I set temp to 70 the furnance isn't going to kick on because "thermostate" thinks it's 78 degrees. This is how to reset this "cheaply" made thermostate - Place in the freezer for like 3 minutes periodically checking to temperature is reach in biggest room in house then reinstall. Oddly Honeywell built this junk but don't know how to reset.

This video says these do have batteries. Here is his video showing how to change them: kzfaq.info/get/bejne/bLx7otp9vcypgqM.html Is it a battery or something else?

Correct. When it goes bad. Take a hammer and smash it Inside you will see a flat round battery

These are NOT battery free bro

These suck