No matter what type of thermostat your home has, it is essential that it is working correctly and measuring your home’s temperature accurately. Thermostats need to be recalibrated every so often as they can have issues that cause them to read the temperature as higher or lower than what it actually is. Testing to see if your thermostat is measuring temperature accurately is fairly easy, and here is a quick overview of how to do it and also what to do if your thermostat isn’t accurate. Experts recommend that you test your thermostat once a year.
Testing Your Thermostat for Accuracy
To test your thermostat for accuracy, you will need to use a thermometer that you know is accurate. A digital thermometer will work, but we would recommend using a candy or meat thermometer, as these are easier to check for accuracy before testing your thermostat. To check if your thermometer is accurate, all you need to do is put it in a pan of water on the stove. As soon as the water starts to boil, take the thermometer out and check its temperature reading. If the thermometer shows exactly 212 degrees Fahrenheit, you can be certain it is accurate.
Once you know your thermometer is accurate, you’ll want to tape it on the wall a few feet away from your thermostat at the exact same height. Before taping the thermometer to the wall, fold a paper towel a few times and place this in between the thermometer and the wall. The paper towel will create a barrier so that the thermometer isn’t measuring the temperature of the wall itself, which is important as otherwise, your reading won’t be that accurate.
After taping the thermometer to the wall, wait for 20 to 30 minutes and then check both the thermometer and the thermostat to see what the temperature reading is on each. Ideally, both will show the same temperature, but a small difference between the two is also fine. As long as the temperature difference between the two is no more than 3 degrees, your thermostat should be accurate enough to prevent any issues. If the temperature difference is greater than 3 degrees, you will then need to try to determine what the issue is and possibly recalibrate your thermostat.
The reason that up to 3 degrees difference is normally fine is that your thermostat will still signal your heating or air conditioning to run before the house gets too cold or too hot. If there were a 5-degree difference, your comfort would be affected.
Let’s say you have your heat set to 68 degrees. Whenever the temperature drops below this, the thermostat will then signal your heating system to run. If your thermostat isn’t accurate, it may not signal the system to run until the actual temperature is only 63 degrees. Alternatively, your heating system may not shut off until your home is 73 degrees if the thermostat registers a cooler temperature than what the home really is. This would keep your home warmer than you intended and may result in higher heating costs than you expected.
What to Do If Your Thermostat Isn’t Accurate
If you have a manual or programmable thermostat that isn’t accurate, the first thing you’ll want to do is remove the cover and try to gently clean any dust and debris from it using a soft cloth or a cotton swab. We wouldn’t recommend using a vacuum or compressed air as this could potentially damage the sensitive components. If you notice any rust or corrosion on the thermostat, we would recommend having an HVAC technician clean it or have a new unit installed.
The reason you’ll want to clean your thermostat is that dust can basically insulate it and prevent it from getting an accurate temperature reading. If you have a smart thermostat, cleaning isn’t necessary as these are typically sealed so that no dust can get inside.
If you have an older manual thermostat, you will also need to make sure that it is perfectly level. The reason is that most of these thermostats use a small vial of mercury to measure the temperature. If the mercury vial isn’t perfectly level, then the thermostat won’t be very accurate. You can check this by placing a bubble level on top of the thermostat and then looking to see if the bubble is in between the two lines. If your thermostat isn’t level, you will need to try to level it as best as you can. That being said, we would always recommend upgrading to a programmable or smart thermostat if you still have an old manual unit, as a new thermostat will be more accurate.
After cleaning the thermostat and making sure it is level, you will then want to use your thermometer to test your thermostat for accuracy again. If the thermostat still isn’t accurate and shows more than a 3-degree temperature difference from the thermometer, it means the thermostat needs to be recalibrated.
How to Recalibrate a Thermostat
Recalibrating a thermostat is sometimes something you can do on your own. However, the specific process for doing so can vary quite a bit depending on the brand and type of thermostat. If you still have the original owner’s manual, this should tell you exactly what you’ll need to do.
Calibrating a manual thermostat can be quite tricky as you will typically need to make small adjustments by turning a screw inside the unit. In this case, we would again recommend replacing it with a new unit or at least having a technician calibrate it for you.
Calibrating programmable and smart thermostats is usually a bit easier, as you can usually do this by going into the unit’s settings. Still, if you’re unsure what to do, it is always best to have a technician calibrate it for you.
Why Thermostat Location Is Important
Oftentimes, many thermostat issues are related to the location of the unit, as this can impact the thermostat reading. For instance, if your thermostat is on an exterior wall or within a few feet of any windows or doors, it will usually lead to the thermostat thinking the home is cooler than it actually is during the winter. Similarly, if your thermostat is in a location where it receives direct sunlight, it will always register a warmer temperature whenever the sun hits it. If the thermostat is located too close to any vents, the cold air from your AC and warm air from your furnace will also affect its ability to gauge the temperature accurately.
The ideal location for a thermostat is in a central part of the home in a room that you spend lots of time in. It should also be in a place with good air circulation, which is why hallways are typically a bad choice. If your thermostat isn’t in an ideal location, we would recommend having it moved, as this can help to improve your comfort and lower your energy costs.
Contact the Pros
At Polar Air & Heating, Inc., our technicians can help if you need your thermostat recalibrated or if you need a new thermostat installed. We have been offering high-quality heating and air conditioning services for the residents of Las Vegas, NV since 1998. We install, maintain and repair heating and cooling systems. We also offer indoor air quality and light commercial refrigeration services.
Contact us today if you have any questions about your home’s HVAC system or need to schedule a service appointment.