How often do AC thermostats go bad?

Author: Shyann Conn  |  Last update: Thursday, June 12, 2025

As with any system, eventually, your thermostat will become outdated. Modern home thermostats tend to have about a 10-year lifespan but are usually replaced sooner due to innovations in the market. Non-programmable thermostats have become outdated and replaced by programmable (or learning) thermostats.

What are the symptoms of a bad AC thermostat?

A bad thermostat can be detected when your AC or furnace is not turning on, your HVAC systems are not turning off, the thermostat not responding, your HVAC system is short-cycling, the room temperature not matching the temperature displayed on the thermostat, and the programmed setting resetting themselves.

How common is it for a thermostat to go bad?

Most household thermostats will last about ten years. As they get older, they start to malfunction and become unreliable. If your thermostat is more than a decade old and is not working as well as it once did, it may be time to pick a new model.

How do I know when my thermostat needs replacing?

Signs that You Need to Replace Your Thermostat

Registering wrong temperatures. High energy bills. Inconsistent temperatures through the house. The thermostat won't turn on or a blank screen (and it isn't the batteries)

How much does it cost to replace a thermostat in a HVAC system?

The average cost of a new thermostat, including installation, ranges in price from $50 to $500 or more based on several factors including the type of thermostat, labor costs, the complexity of the installation, and more.

How often do thermostats go bad?

Can I replace AC thermostat myself?

In most cases, installing a new thermostat is a relatively simple do-it-yourself project that can result in improved comfort and convenience and one that can help you save energy.

How much do contractors charge to install thermostat?

The cost to install a thermostat is $182 on average, but you could pay between $113 and $264. Thermostats play an important role in our daily lives, cooling us down during the sweltering summer heat and keeping us warm and cozy during winter. While the average cost to install a thermostat is $182, pricing can vary.

What is the average life of a thermostat?

On average, most thermostats last about 10 years, depending on the model, usage, and proper maintenance. However, many people decide to replace their unit sooner to take advantage of new energy-saving technologies.

How do I test my thermostat?

Methods for Testing Your Thermostat
  1. Just Turn it On and Let it Work. One way to test your thermostat is to simply turn it on and see if it cools the room down. ...
  2. Get an Indoor Thermometer. Another way to test your thermostat is to use a thermometer. ...
  3. Use a Multimeter. ...
  4. What to Do if You Notice an Issue.

How many hours does it take to replace a thermostat?

Installation typically takes about 1 hour.

Will you get a code if your thermostat is bad?

P0128 is an extension of OBD-II code P0 which indicates a problem with your car's coolant thermostat.

Can a bad thermostat cause AC not to cool?

When your thermostat is working correctly, you can keep it as cool or warm as you need. A bad thermostat can cause your AC to not cool or heat the room to the desired temperature. Air conditioning concerns are more apparent: Your thermostat is one of the best indicators of your air conditioning system's health.

Can a thermostat last 20 years?

On average, thermostats tend to last around 10 years with proper maintenance and care. That said, if it's been more than a decade since you installed a new thermostat, it's likely time to replace your current unit. Older models may become outdated or require more frequent repairs due to wear and tear over time.

How long should a AC thermostat last?

As with any system, eventually, your thermostat will become outdated. Modern home thermostats tend to have about a 10-year lifespan but are usually replaced sooner due to innovations in the market.

Will resetting my thermostat fix my AC?

Any time you are having an issue with heating and cooling units, such as after a sudden power failure or after your children have had 'control' of the system while you've been away, resetting the thermostat should be the first thing you try when attempting to rectify HVAC system issues.

How to tell if an AC thermostat is bad?

7 Ways to Tell Your Thermostat Is Broken
  1. The Thermostat Has No Power. ...
  2. The AC or Furnace Won't Turn On. ...
  3. The Heater or AC Won't Turn Off. ...
  4. The Thermostat Reading Doesn't Match the Room Temperature. ...
  5. The Thermostat Doesn't Respond. ...
  6. The HVAC System Is Short Cycling. ...
  7. The Thermostat Forgets Programmed Settings.

How do you know if you need a new thermostat?

If your thermostat has fresh batteries but suddenly lacks power, flashes, or isn't responsive to adjustments, it may need replacement. If resetting the thermostat doesn't resolve the problem, you may have wiring problems or faulty components causing your thermostat to not turn on.

Why is my thermostat not communicating with my AC unit?

Faulty Wiring

If the wiring between the thermostat and the air conditioning system is faulty, the system may not turn on. This can happen if the wiring is old or if it has become damaged over time. To fix this issue, you may need to call a professional HVAC technician to inspect and repair the wiring.

How often do thermostats fail?

Thermostats can often go bad after about 10 years of use. If you have either bought an older vehicle or you have not checked yours in a long time, then you need to be able to recognize the signs that the thermostat may not be working.

Can I replace my own thermostat?

Upgrading to a new thermostat can feel daunting, but with a systematic approach, it's a manageable DIY project. This guide will walk you through each step, ensuring a smooth and successful installation.

Do I need an electrician to replace a thermostat?

Yes, many smart thermostats are designed for DIY installation, and manufacturers typically provide step-by-step guides and videos. However, if your HVAC system is older or lacks proper wiring (like a C-wire), the installation might become more complex, and you may need professional help.

Does HVAC install thermostats?

Typically, a new HVAC system will include a thermostat with the installation. However, before your technician begins purchasing and installing parts for your home, you may want to specify if you want a smart thermostat for your home.

How much does a mechanic charge for a thermostat?

Car thermostat replacement time is 30 to 60 minutes, depending on the make of the car. It will cost you around $190 to $350, including labor. Thermostat repairs usually take more time, requiring extra time to diagnose and analyze the vehicle's thermostat. It can take up to 2 hours.

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