How Many Ecobee Thermostats Do I Need?

If you’ve got a big home with multiple floors or a wide, open layout, chances are that one Ecobee thermostat won’t cut it.

That’s because one unit won’t offer enough control over your entire HVAC system, and you’ll probably end up wasting energy.

So how many Ecobee Thermostats Do You Need?

The number of Ecobee thermostats you’ll need will depend on a number of factors, like the size of your home, the HVAC system and its zoning, and more.

Keep reading to find out how to calculate exactly how many you’ll need, along with tips for installation and maintenance. 

Key Points

  • Multiple Ecobee thermostats are needed for homes with multiple floors or HVAC zones to achieve individualized temperature control, optimize comfort, and improve energy efficiency.
  • The number of thermostats required depends on factors such as the size and layout of the home, type of HVAC system, number of HVAC zones, and existing thermostats.
  • Each Ecobee thermostat can control one HVAC zone, so the number of zones determines the number of thermostats needed.
  • Professional installation is recommended.

Why Do I Need Multiple Ecobee Thermostats?

Why Do I Need Multiple Ecobee Thermostats

You need multiple Ecobee thermostats if your home has multiple floors or HVAC zones. Each thermostat will control one zone of the HVAC system, which allows for individualized temperature control. This can optimize comfort and energy efficiency, particularly in large houses.

Using multiple Ecobee thermostats in your home comes with a host of benefits, like lower energy bills, improved climate control, and better comfort. But first, you need to find out exactly how many you’ll need.

How to Find Out How Many Ecobee Thermostats You Need

A marketing image of the 2019 ecobee SmartThermostat black model with the temperature being displayed on screen.
The black 2019 ecobee SmartThermostat model.

Determining the number of Ecobee thermostats you need isn’t a one-size-fits-all answer. It depends on a few key factors:

Size and Layout of Your Home

The size and layout of your home play a key role in how many Ecobee thermostats you’ll need. If you live in a small apartment, a single unit might suffice.

But if you have a large house with multiple floors or a complex layout with several rooms, you’ll likely need two or more. 

Why? Because different areas of your home will have different temperature needs. For example, your basement might be naturally cooler than your upstairs bedrooms, which get more exposure to the sun.

By having multiple thermostats, you can keep the perfect temperature in each area of your home and avoid wasting energy too.

Type of HVAC System

Type of HVAC System

The type of HVAC system already installed in your home is important: they may handle thermostats differently. Systems like forced air, radiant heat, or ductless mini-splits each have unique characteristics that can influence how many Ecobee thermostats you need. 

Forced air systems, for instance, can often be managed with a single thermostat, unless your home is significantly large or divided into distinct climate zones.

On the other hand, homes with radiant heat or ductless mini-split systems might require individual thermostats for different zones or rooms. 

Number of HVAC Zones

Now, let’s talk about HVAC zones. An HVAC zone is a designated area in your home that is controlled independently from other areas. This means you can set different temperatures for different zones, depending on your comfort needs.

For instance, you might want your living room to be warmer than your bedroom. With a zoned HVAC system, you can do just that.

But here’s the catch: one Ecobee thermostat can only control one HVAC zone. So however many zones you already have in your home, you’re going to need a separate thermostat for each one. Otherwise, you won’t be able to control them properly. 

And in case you’re planning on expanding your home or adding more zones to it for finer control, you’ll also need to add more Ecobee thermostats accordingly. 

Remember, having multiple thermostats won’t automatically give you more HVAC zones. You’ll also need more zone control panels, dampers, and other hardware and connect them all together to set this up properly. This may require an HVAC professional. 

Existing Thermostats

Existing Thermostats

The number of existing thermostats in your home can also give you a clue about how many Ecobee thermostats you’ll need. If you’re replacing your old thermostats with smart Ecobee models, you’ll typically need one Ecobee for each existing thermostat.

This is because each thermostat usually controls a separate zone in your home.

However, keep in mind that this isn’t always the case. Sometimes, an old home might have multiple thermostats controlling the same zone. This is rare because it’s quite inefficient, but it can happen in large homes with unusual layouts, or even due to an incorrect installation. 

In this case, one Ecobee might do the trick. Or you might consider upgrading your HVAC system to add zones to it. If you’re proficient yourself, you could check the HVAC wiring and see if different thermostats are controlling the same zone or not. 

Personal Comfort 

Lastly, your personal comfort preferences can influence the decision. Some people prefer having the same temperature throughout their home. While others prefer different temperatures in different rooms. You might care more about energy efficiency than the initial setup cost. 

If you fall into the latter category, having multiple Ecobee thermostats can help you customize the temperature in each room to your liking and save the environment while you’re at it.

How to Install and Set Up Multiple Ecobee Thermostats

How to Install and Set Up Multiple Ecobee Thermostats

Setting up multiple Ecobee thermostats in your home can be pretty challenging, so don’t be afraid to get the help of an HVAC professional. Here’s a simple guide to get you started:

Step 1: Choose Your Locations

First, you need to decide where each Ecobee thermostat will be installed. You should install them in places that accurately represent the average temperature of your zones. Don’t place them near windows, vents, or in direct sunlight. But also place it in a convenient spot. 

This is why hallways and common passages are ideal for thermostats. If your existing thermostat locations are fine, you can just use them to avoid the hassle of rewiring and drill work. 

Step 2: Install the Thermostats

Install the Thermostats

For the physical installation of your Ecobee thermostats, you’ll need to follow the instructions provided in the Ecobee installation guide. This typically involves:

  1. Switching off the power to your HVAC system to ensure safety.
  2. Removing the old thermostat, taking note of the existing wire connections.
  3. Installing the Ecobee backplate, making sure it’s level for the best performance.
  4. Connecting the wires to the respective terminals on the Ecobee thermostat.
  5. Attaching the thermostat to the backplate.

Remember to take photos of your original wiring before you disconnect your old thermostat—it can be a helpful reference. And on some old systems, you may not have a C-wire, for which you may need to install a Power Extender Kit. 

This DIY approach to installing a thermostat may save you money, but it can be pretty challenging. If you’re uncomfortable performing these steps yourself, consider hiring a professional to avoid any potential accidents.

Step 3: Connect to Wi-Fi

After physically installing your thermostats, you’ll need to connect each one to your home’s Wi-Fi network. The Ecobee thermostat has a built-in setup guide that will walk you through the Wi-Fi connection process. Make sure the Wi-Fi signal in the installation area is strong to avoid connection issues.

Step 4: Set Up in the Ecobee App

Set Up in the Ecobee App

With your thermostats installed and connected to Wi-Fi, it’s time to set them up in the Ecobee app. This involves giving each thermostat a unique name (like “Upstairs” or “Living Room”), setting your preferred temperatures, and configuring any other settings that suit your lifestyle. 

The app is user-friendly and intuitive, making this step a breeze. And don’t worry, it’ll keep ‘learning’ your preferences as you use it, so it’ll get better with time and automatically adjust itself. 

Step 5: Group Your Thermostats

When you have multiple thermostats, Ecobee allows you to group them together in the web portal. Make sure you set them to share the ‘System Mode’. And you don’t have to worry if you have different Ecobee models: they’re all compatible with each other. 

Grouping your thermostats enables them to work in harmony, preventing any conflicting signals to your HVAC system. This is particularly useful in maintaining a consistent temperature across different zones in your home and adds to energy efficiency. 

Step 6: Install and Pair Room Sensors (Optional)

If you’ve got any Ecobee room sensors, you can install and pair them too. Room sensors monitor the temperature in specific areas, providing your Ecobee thermostats with additional data to optimize your home’s comfort and energy efficiency. 

Install them in the rooms you want to monitor, then pair them with your thermostats using the Ecobee app. 

Verify Your Setup

An ecobee room sensor

Once you’ve finished setting up your Ecobee thermostats, it’s a good idea to test them out and make sure they’re working as expected. Try adjusting the temperature set points or scheduling some events, then check back at regular intervals to see if the temperature changes. 

If everything is working correctly, you’re done! You can now enjoy the benefits of a smarter home powered by multiple Ecobee thermostats (and room sensors). But if you do face any issues with the installation, don’t hesitate to contact an HVAC professional.

Maintenance Tips for Ecobee Thermostats

Maintaining all your Ecobee thermostats is key to optimal performance and long life. So follow these tips consistently:

Regular Cleaning: Dust and dirt can accumulate on your thermostat, affecting its performance. Regularly clean your thermostat with a soft, dry cloth to keep it dust-free. 

Software Updates: Ecobee periodically releases software updates to improve performance and add new features. While this process is generally automatic, make sure your thermostats are always updated to the latest firmware version.

Professional Check-Up: It’s generally a good idea to have a professional HVAC technician come and check the whole HVAC system at least once or twice a year. With proper servicing and maintenance, the entire unit will work smoothly and last longer. 

Common Challenges With Multiple Ecobees (and Solutions)

While using multiple Ecobee thermostats can offer many benefits, you might encounter some challenges along the way. Here are some common issues and how to solve them:

Thermostats Working Against Each Other

This is a common problem with multiple thermostats, whether smart or not. They tend to work against each other sometimes. For example, one thermostat might call for heating while another will call for cooling.

Solution: Group your thermostats together in the Ecobee app. Then, make sure they are sharing the ‘System Mode’. This allows the thermostats to work cooperatively, preventing them from sending conflicting signals to your HVAC system. 

Sometimes there can be an issue with the zone control board, in which case you may need to get a technician to check and fix it. 

Temperature Readings Aren’t Accurate


Sometimes the thermostats don’t read or display accurate temperatures, which affects their heating/cooling too. This could be due to the placement of the thermostat, its sensor calibration, or even ‘wall draft’. With multiple Ecobees having the wrong temperature, the problem gets even worse. 

Solution: First, open up the thermostat panel and look behind the wires. If there are a lot of gaps, then there may be a draft of air coming through the HVAC and messing with the temperature readings. Insulate these gaps properly, and then ensure your thermostats are placed ideally — away from sunlight and any heat sources. 

If that doesn’t fix it, check the sensor calibration. Try resetting or recalibrating the device. 

Connectivity Issues

Like any smart device, Ecobee thermostats can sometimes experience connectivity issues. They may disconnect from the network and not respond to your requests while changing the temperature. This can cause more issues with grouped Ecobees. 

Solution: Ensure your Wi-Fi network is stable and strong enough to support multiple devices. Consider adding a new Wi-Fi router, a few repeaters, or getting a technician to help improve your home network. 

If you still face issues despite having a strong network, try factory resetting your thermostat and make sure it is upgraded to the latest firmware. Else, contact Ecobee’s customer support.

Remember, if there are persistent connectivity issues, then the grouped thermostats will not be able to coordinate their functions. 


To sum up, figure out the number of Ecobee thermostats you need by checking all the factors above. Generally, the number of HVAC zones or existing thermostats can help point you to the right number. If you’re handy at DIY work, you can install them yourself by following Ecobee’s guides and a bit of electrical wiring. If not, hiring an HVAC professional is always a good idea to ensure everything is set up correctly.

With the right number of Ecobee thermostats installed in your home, you’re well on your way to a smarter, more efficient, and more comfortable home.


Can one Ecobee thermostat control multiple zones?

No, one Ecobee thermostat can control only one HVAC zone. If you have multiple zones in your home, you’ll need an Ecobee thermostat for each zone. These thermostats are usually connected to a zone control board, which controls the opening and closing of dampers in your ductwork to direct airflow to the desired areas.

How many Ecobee thermostats can I have in total? 

According to Ecobee, you can have a total of 16 thermostats linked to your account. That should certainly cover most residential properties. But if you need more, you can opt for their SmartBuildings solution for commercial units. 

How do Ecobee room sensors work?

Ecobee room sensors are small, wireless devices that detect temperature and occupancy in different areas of your home. They communicate this information to your Ecobee thermostat, which adjusts the heating or cooling based on the data received. They’re battery-powered and portable, so you can keep them wherever you like. 

These room sensors are especially useful in homes with multiple zones. They provide a more accurate picture of the temperature in different areas of your home, allowing your Ecobee thermostats to control your HVAC system more efficiently.

About Tristan Perry

Tristan Perry is a software developer who is passionate about tech gadgets, DIY and housing. He has therefore loved seeing smart homes hit the mainstream. Tristan also has an academic background (in Math & Computer Science), and so he enjoys digging into the technical ways that smart home devices work.

Tristan owns close to a dozen Amazon Echo devices, way too many Philips Hue bulbs and lightstrips, a boat-load of Ring Cameras and Doorbells... and a bunch of other smart home devices too (from Reolink, Google Nest, GLEDOPTO and others).

If you have any questions, feedback or suggestions about this article, please leave a comment below. Please note that all comments go into a moderation queue (to prevent blog spam). Your comment will be manually reviewed and approved by Tristan in less than a week. Thanks!

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