When the heating or cooling doesn’t turn on, many homeowners automatically assume there’s a problem with their furnace or air conditioner. Before your call a professional technician, check your thermostat!
In addition to keeping your Resolutions for a Cleaner Home this year, changing the batteries in your thermostat is a periodic chore that everyone should know how to do.

Thermostat Q & A

Q: How often should I replace my thermostat’s batteries?
A: Once annually—recommended at the beginning of a high-usage season such as winter—or whenever the low battery indicator appears. Some batteries can last as long as 5 years while others might not make it 3 months. Even if your thermostat is hardwired, it will probably have a back-up battery that will need to be periodically replaced. But don’t be upset—the back-up battery allows your system to work even if there is a glitch in the power system. Otherwise, you would have to reprogram the thermostat every time the power goes out. If you have an older mechanical model with a mercury switch, you may not need batteries, but other troubleshooting fixes may be required, such as adjusting the anticipator and dusting the coils. You will be able to tell if your thermostat requires batteries by removing the front cover.

Q: How will I know when the batteries are low?
A: There will be some sort of low battery symbol that creeps up when the batteries are low. It may be a battery symbol or a flashing light. Most digital thermostats are programmed to tell you about a month or so prior that the battery is going to die. If you don’t already keep extra batteries, then you’ll have fair warning you need to grab some. In other words, it shouldn’t really be a surprise when your thermostat batteries stop working. Be prepared with backup batteries.

Q: What will I need?
A: A flat-blade screwdriver and new batteries.

Q: What batteries will I need to buy?
A: The battery is dependent on the thermostat. Read your owner’s manual for more information or simply look at the batteries that are already in use and replace them with the same. Most likely your wall thermostat will use 3V lithium batteries, AA, or AAA alkaline batteries. We recommend going for the more powerful lithium batteries if possible.

Q: Why are batteries even important?
A: Changing your thermostat’s batteries are important because even if there’s a power outage, batteries retain the thermostat settings so you won’t have to reprogram them. Additionally, if you’re having trouble with your heating and cooling system, low batteries in your digital thermostat could be directly to blame. If your thermostat isn’t working, your HVAC system won’t either.

Q: How do I replace my wall thermostat’s batteries?
A: Consult your owner’s manual. The process for replacing batteries varies by make, model and manufacturer.
General steps are as follows:

  • Flip up or pull off the thermostat housing (this is normally the hardest part).
  • Locate the batteries.
  • Take out the old batteries with your hand. If you need to use your flat-head screwdriver for assistance, be gentle.
  • Put in the new batteries as marked.
  • Flip shut or snap the thermostat housing back onto the wall plate.
  • Reprogram your thermostat settings if necessary.

For help removing your thermostat cover, watch this video:

If your furnace stops working this winter, check your thermostat’s batteries! Once the batteries are replaced, go over your owner’s manual to learn how to use all of the features properly:

  • Make sure switch is set to “heat” for heating and “cool” for cooling.
  • Set the desired temperature.
  • Compare the thermostat temperature to the room temperature. The heating system will only kick on if the temperature is higher than the room temperature.
  • Check the day, time, and a.m./p.m. settings. Replacing the battery may have reset the date and time.
  • If you notice any problems with your electrical wiring, consult a professional electrician.
  • Periodically dust the inside and outside of your thermostat.
  • Make sure the thermostat is completely level.
  • If you are having trouble setting your thermostat, you can alway bypass the settings by setting the desired temperature with the up and down arrows and then pressing down on the hold button.

If these thermostat troubleshooting tips don’t solve your heating or cooling problems, call OnTime Service for professional advice and service appointments.

Call OnTime Service to schedule your annual heating inspection at (205) 872-1944 .

Our experienced team of technicians is fully trained to handle any heating or cooling system. As always, we will troubleshoot your home and give you straightforward pricing options before any work begins.
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