The only reason it may change by itself is you have a programmable thermostat that has a schedule running on it. Either that or someone is moving it without your permission. Assuming it's the first, try locating the “hold” button.
Problem: Old Batteries
Most newer programmable thermostats connect to your home's electrical or HVAC system for power. Solution: Switch out your batteries. It can be as simple as switching out the batteries on your thermostat device.
If your home is enrolled in a utility-run energy-saving program, your system can automatically adjust your thermostat.
One of the most common reasons for a thermostat to reset itself is old batteries. If you haven't changed them recently, replacing them with new batteries is a good first step.
If you have a programmable thermostat, you need to look for the 'hold' button. Manually turn the temperature up, or down to the desired setting, then press the 'Hold' button once. The word 'hold', or 'permanent hold', or something similar should appear on the digital thermostat.
The average cost of a new thermostat, including installation, ranges in price from $50 to $500 or more based on several factors including the type of thermostat, labor costs, the complexity of the installation, and more.
The Lifespan of a Thermostat
On average, most thermostats last about 10 years, depending on the model, usage, and proper maintenance. However, many people decide to replace their unit sooner to take advantage of new energy-saving technologies.
If the temperature is set to 74°F but the thermometer shows 78°F, you will have to recalibrate the thermostat to account for this 4-degree deviation. Even with older AC units or furnaces, you might have to recalibrate your thermostat from time to time.
Your thermostat instruction manual can tell you exactly how to change a thermostat. Installing the thermostat yourself is an easy task that will typically take about an hour from start to finish.
This is called a demand response event. Now, this doesn't mean that your air conditioner will turn off, and you'd be sitting in a very hot room. With such an event, the thermostat changes by itself, and the temperature is only increased by a few degrees.
A common oversight for a thermostat showing the wrong temperature is the state of its batteries. Dead or low-power batteries can lead to inaccurate readings. Simply replacing the batteries might restore your thermostat's accuracy and functionality.
Try checking the circuit breaker box or replacing the batteries. Bad wiring: The thermostat may be unresponsive if the wiring has gone bad. Remove the cover and check inside for loose, detached, or corroded wires. If you spot any problems, contact an HVAC technician for assistance.
Yes, many smart thermostats are designed for DIY installation, and manufacturers typically provide step-by-step guides and videos. However, if your HVAC system is older or lacks proper wiring (like a C-wire), the installation might become more complex, and you may need professional help.
A malfunctioning thermostat will have trouble keeping your home's temperature at the right setting. If there's something wrong with the motherboard, it may change its own settings at random. You can test the thermostat by lowering the settings to see if the problem persists.
The lifespan of most home thermostats is 10 years. However, you may need to replace yours sooner as newer, more efficient thermostats enter the market. You may, for instance, want to replace a non-programmable thermostat with a programmable option.
One of the lesser-known issues is the polar opposite of overheating. Overcooling happens when the engine does not reach the right temperature for its normal function. In this scenario, the thermostat is stuck open and overflows the radiator with coolant, drastically reducing the engine life cycle.
Uneven Heating
Inconsistent heating patterns often point to thermostat inaccuracies, as the device struggles to regulate the temperature evenly. On the other hand if the entire house feels uniformly cold then the furnace might be the problem.
P0128 is an extension of OBD-II code P0 which indicates a problem with your car's coolant thermostat.
Old Batteries
This is one of the most common reasons why your thermostat changes temperature on its own. In this case, putting new batteries in your thermostat should solve the problem.
Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it. For those wondering specifically how to reset air conditioner thermostat models, the process is generally the same.
You should always turn off the power before you connect or disconnect any wires from your Google Nest thermostat, and you should test to make sure that the power is off. This helps protect you and your equipment during installation or troubleshooting.