How to Change the Batteries in a Honeywell T4 Thermostat

Whether it’s hot or cold outside, a faulty thermostat can be a major headache. Luckily, not all heating and cooling problems are big ones. Sometimes all you need is a new set of batteries. This tutorial will show you the steps for how to change the batteries in a Honeywell T4 thermostat. Don’t worry: it’s simple. Let’s get started.

What you’ll need:

  • Two AA batteries

Step 1: Remove the thermostat

Removing the Honeywell T4 Pro thermostat is simple: just pull it from the wall. Pull gently, and wiggle it a bit if necessary. It should pop off easily.

Step 2: Remove the old batteries

Unlike with other versions of the Honeywell thermostat, there is no internal battery compartment. You can easily access the batteries on the back of the thermostat. Remove the old batteries.

Step 3: Replace the batteries

Replace the old batteries with two new batteries. Make sure they’re AA. Also, note the direction of the batteries before you insert them: the positive and negative ends should match those in the battery compartment.

Step 4: Replace the thermostat

Replace the thermostat by pushing it back onto the attachment plate on the wall. Gently press — it should click easily into place.


Congrats: you now know how to change the batteries in a Honeywell T4 thermostat. After installing the new batteries, your thermostat should turn back on immediately. If the thermostat has been without power for more than a couple minutes, you will need to reprogram it.

Your heating and cooling system should be back to normal. However, if it turns out that your issues are bigger than bad batteries, reach out to our service team and we’ll help you out.

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