When the temperature you need in one of your home’s rooms has to be higher or lower than the rest of the house, you have most probably wondered whether you can save money by rather having two thermostats controlling the same zone than installing a second HVAC system. The question is whether it is possible to use two thermostats to control one Zone. 

Yes, in principle, you can use two thermostats to control one HVAC zone. If correctly installed, set, and used you can actually save on your electricity bill. You can also connect more than one thermostat to a single HVAC unit.

In this article, we’ll shed some more light on the possibilities and implications of using two thermostats to control one zone.

It is possible to use two thermostats in one zone

In principle, it is simple and easy to use more than one wall thermostat to control a specific heating or cooling zone. It is often a handy way to differentiate between the temperature needed in different locations in your home without the need to install another expensive HVAC system. 

However, sometimes two thermostats controlling the same zone can “confuse” your HVAC system if one thermostat is, for instance on cool mode and the other one has accidentally been switched to heating mode.

To utilize two thermostats fully, ensure that the two thermostats are installed correctly. 

Wire correctly

You simply have to wire up two thermostats in parallel. Either or both will then be able to turn the HVAG appliance on or off. 

However, although it is possible to use two, or even more, temperature sensors or thermostats to control a single zone in your house, you might encounter problems wiring the thermostats in parallel. Fortunately, there are videos available showing you how to install the second thermostat. If needed, contact a professional electrician or HVAC expert to assist you.

Example of two thermostats controlling one zone

The following example explains the use of two thermostats to control one HVAC zone. 

In a two-story house, it often gets warmer upstairs than in the rest of the house in summer. If there is not a zoned HVAC system installed and the system only uses one thermostat, the thermostat controls the temperature but cannot differentiate between the warmer upper story and the cooler lower story. 

A second thermostat can then be installed upstairs without dividing the house into zones. The second thermostat is then set to trigger the blower fan when it gets above the pre-set temperature. This allows the one-zone system to differentiate to a certain extent. 

If the main (downstairs) thermostat is set to 75 the AC will start working without the blower fan when the temperature is 75 degrees. The blower fan will only start blowing when the temperature rises above 77 degrees in the upper story rooms. The running of the blower will even out the temperature difference. The second thermostat also saves electricity as the blower fan is now only running when needed and not automatically when the AC kicks in, 

Other questions regarding the use of two thermostats

When thinking and talking about more than one thermostat controlling a zone, there are other questions that also come to mind. Let’s look at some of these questions.

What is the difference between a zoned system and a multistage system?

A zoned system uses multiple thermostats to control the heating and cooling separately for different parts of the house. A multistage system is a one-zone system where there is more than one level of heating or cooling. 

Can I use more than one thermostat with an HVAC unit?

Most thermostat brands allow you to connect more than one thermostat to the same HVAC appliance. It doesn’t matter whether it is a ventilator, AC, boiler or furnace that is controlling the heat of your house. 

This feature allows you to use multiple ductworks with the result that different areas and levels of your house can achieve a balanced temperature. By using more than one thermostat for the same appliance the possible purchasing of very pricy extra HVAC systems is eliminated.

Can I Sync Two Thermostats?

You may also wonder whether it is possible to sync two thermostats. Most brands are developed in such a way that they allow you to sync multiple thermostats. If you want to sync two thermostats, follow the instructions given in the thermostats’ manuals or provided online. 

Just remember that once synced, they both will be using the same temperature settings and maintenance methods. If the two are installed in different rooms or locations in your home, it will set the same temperature in both places.


Most homeowners would like to have zoned HVAC systems installed in their homes because the temperature in every room or other space in the house can be controlled separately. Unfortunately, this can be pricy. The good news, however, is that a two-thermostat on-zone system can also to a certain extent let you differentiate between temperatures in different locations in your home.


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