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How to Change a Thermostat

Interested in changing your home’s thermostat? Newer models, especially “smart” thermostats, can make your home more comfortable and save you money on energy bills. They’re great at keeping your house at just the right temperature without you having to constantly adjust it. Plus, they can learn your routine and heat or cool your home only when you need it. This means you won’t waste money cooling an empty house. Additionally, these advanced thermostats can be controlled remotely via smartphone apps, allowing you to adjust your home’s temperature from anywhere.

Knowing how to change a thermostat is a useful skill, and it’s a fairly DIY project that many homeowners often tackle themselves. In this blog, we’ll guide you through the process, including how to replace the battery to ensure a smooth transition. We’ll explain:

  • How to determine your thermostat type
  • How to remove the old thermostat
  • How to install a new thermostat

We’ll also explore the benefits of having a professional install one for you, as they can ensure it’s set up correctly and efficiently from the start. 


Want a smart thermostat for your Phoenix home? Call Champion Air for a hassle-free installation.

At Champion Air, we specialize in top-tier smart thermostats like the Lennox iComfort and ComfortSense series. These devices will optimize your energy usage for maximum year-round savings. They’re also a breeze to use, with large bright touchscreens and automated reminders for things like air filter replacements. Call us at 480-748-4000 or click below to schedule online today and take the first step towards a smarter, more comfortable home.

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How to Determine Your Type of Thermostat

To figure out what type of thermostat you have, start by looking at how it operates. If your thermostat uses a simple dial or slider, it’s a basic manual model. If it has a digital display that lets you set schedules for different temperatures throughout the day, it’s programmable. For thermostats with touchscreens or the ability to connect to the internet, you’re looking at a smart thermostat. Also, see if it runs on batteries or is wired directly into your home’s electrical system. This info will help when picking a new one that fits your system. You can usually find more details about your thermostat model by checking the user manual or the manufacturer’s website using the model number on your device. This step is important to make sure you buy a thermostat that will work smoothly with your system.

How to Remove the Old Thermostat

Gather Tools

The first step in changing a thermostat is gathering the right tools and materials. For most scenarios, you will probably need:

  • A Phillips screwdriver
  • Wire labels or masking tape
  • Batteries (if required)
  • Level for mounting (optional)

Power Off

Now that you’ve collected the appropriate tools, it’s time to ensure your safety by turning off the power to your heating and cooling system. Head to your circuit breaker box and turn off the switch that powers your HVAC system. This step is crucial to avoid any electrical hazards while changing the thermostat.

Remove the Thermostat Cover

Most thermostat covers can be gently pried off or unscrewed. This will expose the wires connected to the terminals. Be careful when removing the cover because the wires are delicate and easily damaged. Once the cover is off, take a moment to examine how everything is arranged and consider taking a photo for reference.

Label the Wires

Before disconnecting any wires, label them according to the terminal they are attached to. You can do this by using small pieces of tape or stickers to mark each wire with the corresponding terminal letter or number. Depending on your experience level, this may not be 100% necessary, but it can generally prevent confusion and simplify the installation process.

Disconnect the Wires

Using a screwdriver, loosen the terminal screws and carefully remove the wires. Make sure they don’t fall back into the wall. Then, unscrew the base of the old thermostat from the wall.

How to Replace Battery in Thermostat

If your issue is a simple battery replacement, this is the perfect time to handle it. First, locate the battery compartment (usually on the back of the thermostat or inside the cover). Then, remove the old batteries and insert new ones, ensuring they are positioned according to the indicated polarity. Once the batteries are in, reattach the cover and turn the power back on to test the unit.

How to Install the New Thermostat

Now to the fun part, replacing your thermostat with a new one!

Mount the New Base Plate and Connect Wires

Place the new base plate against the wall where the old one was installed. Use a level to make sure it’s straight. Mark the screw holes with a pencil. If the new holes do not align with the existing ones, drill new holes and possibly insert drywall anchors. Then, attach the wires to the corresponding terminals on the new thermostat, per the labels you made earlier. Make sure each connection is tight.

Attach the Base and New Thermostat

Screw the base plate into the wall, ensuring it’s firm and level. Depending on the model, you’ll either snap the thermostat onto the base or secure it with screws. Once everything is assembled, restore power to the circuit breaker.

Program and Test the Thermostat

Follow the manufacturer’s instructions to set up and program your new thermostat. This may include setting the date and time, adjusting the temperature, and configuring Wi-Fi for smart thermostats. When finished, turn on your heating or cooling system to see if the new thermostat controls the temperature effectively.

If the thermostat doesn’t seem to be working correctly, double-check that all wires are properly connected to their corresponding terminals and that the batteries (if it’s a model that requires them) are installed correctly. If problems persist, consult the thermostat’s manual or contact a professional.

The Benefits of Professional Installation

Hiring a professional to install your thermostat has several advantages. Experienced HVAC pros know exactly how to match your specific heating and cooling system with the right thermostat, which is especially important if you have a modern, complex system. They will also make sure the installation meets all local safety rules and electrical codes, which helps avoid electrical problems later. After installing, they’ll check to ensure everything is working right, which can help your system run more efficiently and reduce your energy bills. Plus, most professional installations have a warranty, giving you extra security if something goes wrong after they leave.


For a top-notch thermostat installation in Phoenix, contact Champion Air!

Make one call to Champion Air, and our highly-trained technicians will help you choose the right smart thermostat for your home. We’ll also provide upfront price quotes and financing options if needed. You can ask questions, share your budget, and feel confident knowing that your thermostat installation is being handled by Phoenix’s most trusted HVAC experts. 

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