Will My Honeywell Vision Pro Thermostat Work Without Batteries?


Yes, your Honeywell Vision Pro Thermostat will work without batteries. 24-volt power comes from the furnace to power the thermostat, and batteries are for backup in case of a power failure. During a power outage, your furnace will be dead.

So, why will you need a backup set of batteries?

You won’t get the correct answer unless you search for the exact version of your thermostat because Honeywell makes more than one version of the Vision Pro 8000 Touchscreen, and each has different battery requirements. Model numbers can be found by removing the thermostat from the sub-base.

With the question of “why are batteries required” in the Vision Pro, I called Honeywell tech support more than once on this issue. I got more than one unsatisfactory answer. My best guess has always been to tell my customers that having batteries may enable the thermostat to retain settings like programming while the power is off.

Another Honeywell tech support person said that a thermostat with batteries will remember its settings for a certain amount of time and then go into a default setting. So I’ll keep searching, and someday the answer will come. For now, it’s just that not all thermostats are the same.

On the chart I’ve linked to, toward the end of this article (this convenient chart) almost all of Honeywell’s digital thermostats have “Permanent Memory Retention” except for the TL8100A1008. So, why do we need batteries?

Honeywell’s Vision Pro line of thermostats requires a power wire and a common wire from the furnace to operate. This power is from the 24-volt transformer in the furnace.

These thermostats require other wires to start the furnace and the air conditioner, but the thermostat will power up and program with just the “R” and “C” wires connected to the furnace.

Running your thermostat without batteries is a good way to prevent leaky batteries from ruining the connectors in your thermostat. I just took the batteries out of my own Honeywell TH8321R1001 Vision Pro with RedLINK and it powered up as expected. RedLINK requires a separate modem to connect to Wi-Fi.

I prefer the TH8321WF1001 (ad) as it links straight to your home modem without the need for the extra Honeywell modem. It’s a less expensive way to go. I don’t know why I bought the RedLINK. It was years ago. The intriguing thing about the TH8321WF1001, it doesn’t use batteries. Check out my article.

Some people buy the TH8321WF1001 because they do their research and find out which Honeywell thermostat does not require batteries. It strictly relies on the power from the furnace to operate.

The RedLINK version registers the temperature and humidity on the touchscreen of the stat and receives the data from a remote wireless sensor mounted somewhere outside of your home. The wireless sensor is an option. The TH8321WF1001 uses the weather data available on the internet for your local area.

Incidentally, the Honeywell Wi-Fi thermostat will work without Wi-Fi. If your Wi-Fi fails, you will still have heat and air conditioning. It just won’t register the outdoor temperature and the humidity,y and you will have lost your remote access to the thermostat.

Is My Honeywell Thermostat Dual Powered or Hard Wired?

A dual-powered thermostat has both batteries and 24-volt power coming from the furnace. Hard-wired only thermostats have no batteries and rely strictly on the 24 volts produced by the low-voltage transformer in your furnace.

Once you have found your thermostat’s model number by removing the thermostat from the sub-base or looking at the original package, you can go to this convenient chart and look up the battery requirements for your particular thermostat.

Scroll over to “Power Method” and down to your model number. Now you know the specific battery requirements for your thermostat, and a lot more information if you’re interested.

To sum it up, you cannot ask generic questions because the different manufacturers of thermostats make a lot of models, all with various battery requirements. This world is constantly changing, and I hope this article opened your eyes to some ways to be more knowledgeable about your Honeywell thermostat.

If you feel I’m in error in my research and experience, don’t hesitate to text or email, I want the information to be correct, not some off-the-wall research done just to get views and ad revenues. You’ll find all my contact info on this site.

Chad Peterson

Chad Peterson is near 40 year veteran of the HVAC industry. "I like to explain heating and air conditioning problems in a way the average home owner can understand. "

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