How To Test A Thermostat?

Testing a thermostat is an important part of maintaining your heating and cooling system. It helps to ensure that the temperature in your home or office remains consistent, while also helping to minimize energy costs.

Testing a thermostat can be done quickly and easily with minimal tools and knowledge. In this guide, we will walk you through the steps on how to test a thermostat so you can make sure it is functioning correctly.

How to Test a Thermostat?

how to test a thermostat

Testing a thermostat can be done in a few simple steps to ensure that it is working correctly. First, check the temperature setting on the thermostat.

Make sure that it is set at the desired temperature for when you will be testing the thermostat.

Let’s say it’s summer time and the temperature inside your home is 79° and you want to cool it down so you lower the temperature to 75°, keep it on cool and the fan setting on auto position.

Now you would expect to see some cool air coming out from your air vents however you don’t feel any.

The same scenario applies for the winter time, if it’s 79° at home and your want to raise it up to 82°, and you obviously would switch it to heat and now you would expect warm air to come out but you still don’t feel any.

If you don’t feel any air coming out from your vents the next step would be to switch the fan settings from auto to on position.

Doing this, your fan should start blowing regular home air non stop regardless of the temperature settings you have on your thermostat.

Whether it’s for cooling or heating and if you still don’t feel any air coming out, there is a chance that you have a bad thermostat. However, that is not conclusive just yet.

To find out exactly, you need to remove the face-plate of your thermostat.

Some plates can come right off by grabbing it from both sides and slightly pulling on them while others come with two clips at the bottom, so you press and hold them while pulling the thermostat face-plate off the wall.

With the face-plate out of the way, you will see a bunch of wires you may have 5 or more or less wires depending on the model of your thermostat.

If you find yourself unfamiliar with the wiring on your thermostat, we recommend exploring our comprehensive guide on “thermostat wiring” to improve your understanding and gain valuable insight.

Now we will walk you through the anatomy  of your thermostat wiring and how it works for you to test your thermostat.

If you have a C terminal wire connected that means it powers up your thermostat directly from the furnace and you won’t need any batteries unless you want to preserve some settings that you programmed in your thermostat that may reset in the event of a power outage.

However, if you own a smart thermostat without ‘C’ wire, you must use batteries and they must be fresh to properly operate the system.

If you haven’t replaced them in a while, it’s always a good idea to buy new ones from the store which may or may not fix your problem.

If your new batteries didn’t fix the problem or you have a C terminal connected then you should try and jump start your thermostat bypassing it with a short insulated jumper wire, which you probably won’t have laying around so you can make a DIY jumper wire out of a metal paper clip.

To make a DIY jumper wire:

Simply straighten the paper clip out and make a U shape out of it.

Next, use electrical tape to insulate the wire from the middle where you would hold it from, and don’t worry about accidentally touch the bare clip as you will be working with a very low voltage, around 24V so it won’t hurt you that much.

However, beware and not touch the C terminal if it is connected for your own safety and you will short and blow the fuse. Now to jumpstart your system you need to connect two terminals.

Let’s start with R terminal (red wire for power) and G terminal (green wire for fan). Simply touch and hold the two screws relative to each terminal. Press and hold, do not wiggle it around since you want constant contact.

After connecting these two terminals the fans should kick in and start blowing air and if you don’t feel any air coming out after a few seconds then it means your thermostat is good but you have some other problems with the system.

In that case you should consult an HVAC technician for assistance. They can help identify any problems and ensure proper operation of the thermostat.

However if you jump the thermostat for fan and you feel the air is blowing, that means you have successfully bypassed the thermostat and jump started the system which indicates that your thermostat is bad and needs to be replaced.

In this scenario only the front face-plate is bad, the thermostat wiring works fine and does not need to be replaced.

Testing a thermostat is not as hard as it may seem. With the right tools and knowledge, you can easily test your thermostat to make sure that it’s functioning properly and reliably.

The first step in testing a thermostat is checking its accuracy with an accurate thermometer or temperature probe.

You should also check the wiring connections between the thermostat and heating/cooling system for any signs of damage or corrosion.


By following the steps mentioned in this article, you will be able to determine if your thermostat needs further repairs or replacement so that you can get back to enjoying comfortable temperatures indoors once again.

In conclusion, testing a thermostat is a crucial skill that can help you troubleshoot temperature inconsistencies in your home. As discussed in this blog post, there are a few key steps to follow.

The key takeaway is the importance of regular thermostat testing to ensure it’s functioning correctly. By being proactive and knowledgeable about testing procedures, you can identify and resolve potential issues before they become major problems.

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