What’s the lowest setting on your current thermostat? Have you considered leaving it on that during the colder months? Is that cost prohibitive? Sorry for not recommending a new thermostat.

Cost prohibitive. Days in the winter months are for the most part above 20 degrees F. Just some cold nights now and then.

A good thermostat with Wifi connectivity will show inside temp on the app

I don't think the OP asked for a new Wifi thermostat but let me check. NOPE the OP is looking for a quality WALL MOUNT DIGITAL THERMOMETER!

Zomtobel, look at companies who build digital thermometers for science and industry where accuracy is critical and required. Cole-parmer would be an example of one where thermometers are calibrated using NIST standards and certified. many of there products are within your price range and one may work for you. But when searching for accuracy all you need to do is make sure the thermometer has certification of it's accuracy by an accredited laboratory and will have a calibration serial number with the unit.

I can explain to you what the OP's need is but I can't help you understand. That's where your stumbling block often is.

Not sure, Elmer, what you are saying. My idea of my Ring camera showing a wall mounted thermometer is a no-brainer and would obviously work. No stumbling block and no difficulty understanding.

Not referring to you.

If you have a Wifi-accessible thermostat, the display the app shows will include the indoor temperature (same as shown on the face of the thermostat if you were standing there looking at it) and often indoor humidity too.

I genuinely don’t understand why you wouldn’t just let a thermostat manage the inside temp instead of having to personally mediate the process between a remotely viewed thermometer and a remotely controlled heater (via a thermostat, right?) That’s what thermostats are for. You yourself are probably the most unreliable link in this system. Do you want to allow the house to get cooler than the min temp in any thermostat?

Susan L, going the WiFi wall thermostat route is what I first planned.

I have two Rinnai natural gas wall furnaces, one upstairs and one in the basement.

When it gets cold, the concern is protecting the plumbing in the basement from freezing.

But here’s why that plan did not work.

I installed a remote thermostat kit on the Rinnai.

But when there is a power outage, the Rinnai defaults to console mode which renders the wall thermostat useless.

And I am 5 hours away.

Unfortunately, power outages in the area are numerous.

So I have no choice but to turn the unit ON when needed and OFF when not needed.

I do this via the MyLeviton app on my iPhone controlling a Leviton D215O plug-in switch.

I like your solution, Elmer, but as you see from my reply to Susan L, not possible for me and my situation.

Maybe you need a fixed generator? Do any of these things- Leviton switch, a camera, your internet connection or the Rinnai- work when the power is out?

The Rinnai has an electronic ignition so does not work without power. But who cares, all I want it to do is to work on some cold nights.

I’m confused with what you’re saying but that’s fine. Good luck

Is there some reason you can't just winterize the plumbing?

There's always going to be a weakness with frozen pipes with a location that has fickle power and no generator.

So, in case of a power outage, what can you do?

Wait until power returns and, if required, turn it back on. Actually, the Leviton D215O defaults to ON after power returns.

The Honeywell system sends me an email when communication is lost from a thermostat location (as with a power outage or, more rarely, the internet connection goes down) and sends another when the power is back on. Likely other thermostat brands work similarly.

Too much confusion here to wade through.

As the OP mentioned there is no stumbling block here either Elmer. Zumtobel asked a specific question and I willfully obliged directly to the question without deviation, I knew where is was going, and who I'm I to question his needs. I also use Wi-Fi 6 (the correct abbreviation if you want to pose as an expert) to view through my wise camera's to monitor automated watering and lighting for my plants encase of a failure when I"m away. I can also control the gadgets I built remotely using Wi-Fi 6, but no big deal.

" I can explain to you what the OP's need is". This is where you stumble and fall on your face in nearly every discussion, but thanks for at least letting me know I wouldn't understand. I feel so stupid knowing Zumtobel has remote access to a ring camera but would not know about Wi-Fi 6 thermostats, darn!

If the need was a Wi-Fi 6 thermostat but you thought I wouldn't understand you're failure was to incorrectly judge a situation and so wrong. Besides HVAC tech training I also spent 2 years in vocational schooling to be an electronics tech. I could of became an accountant but it was just too easy, incredibly boring, and a mindless occupation as I learned working in military finance. Because I luckily dodged a life of boredom and entered the scarly topic of electronic technology so automation and Wi-fi 6 (soon to be 7) is common knowledge to me, as is every bandwidth used to transfer data. Also know how data is modulated within every type of carrier signal,( which still is analog even in a digital world). Cell tower, satellite, Wi-Fi 6, and Bluetooth are no more confusing today than Amplitude modulation (AM) frequency modulation (FM) or television UHF/VHF was back in the 70's, and the basic principles remain the same, so it's nothing new. Please get your facts before trying to insult others.

Now I've never paid a mechanic to work on a vehicle and not about to start paying now even in my old age, and not ready to sit around waiting to die playing a expert on houzz for 15-20 years until I die. My present focus is the bus automotive networking protocols to continue my DIY desire on my cars. I've learned how to program modules and where to get the programming data from the manufacturer thanks to the automotive right to repair act, and a obstacle to completing repairs. Once I find a used bypass device I'm good to go because I'm the master Jack of all trades, seriously just about everything. Honestly you name it I've done it with professional results. BTW Wi-Fi 6 is backward compatible and also a network protocol, remember that when you decide to play pretend.