The thermostat is one of the most fundamental components of an HVAC system, yet people often overlook it. Inaccurate readings from your home’s thermostat may be the reason your HVAC system is having efficiency or performance issues. Whether you have a typical or smart thermostat, are some reasons why the reading might be off.
Located Near Heat Sources
A thermostat should be at least 18 inches away from any heat source. Lights, electronics, and appliances can all produce heat that throws off a thermostat’s readings. This may convince the thermostat that it has reached the target temperature even though other parts of the house could be as much as 10 to 15 degrees off.
If the thermostat is located near a heat source, the first question is, “Can you relocate the heat source?” Moving a lamp or a portable appliance could be the simplest solution. In some cases, however, you may need to ask one of our HVAC technicians to find a suitable location for the thermostat.
Air Drafts
The opposite effect happens when a thermostat believes the home’s temperature is colder than it actually is due to a draft. In the winter, a draft could convince the heater to keep kicking on. This makes your home overly warm and drives up your utility bill.
You also want to be mindful of the thermostat’s location relative to any vents or registers. Blowing conditioned air on the thermostat during a cycle, even from several feet away, could throw the reading off by several degrees.
Calibration Drift
Thermostats use temperature sensors to know when to signal the HVAC to turn on and off. Most modern digital systems use thermistors, while older analog units use bimetallic strips. These devices can experience material fatigue over time, with an average annual drift of about 0.1 to 0.2 degrees. This can cause the temperature to drift significantly after about a decade. If the system deviates too far from its specifications, it may be time to replace the thermostat.
Dust or Debris
Like any system in your house, the thermostat is prone to collecting dust and debris. This ends up insulating the sensors and throwing off the reading. Dust can also make the thermostat less responsive, leading to cycle timing issues. We recommend using a hand vacuum to gently clean the thermostat at least once every six months. Our technicians may also be able to recalibrate the thermostat, but replacement might eventually be necessary.
Faulty Wiring
A typical thermostat draws power from the attached HVAC. Damaged wiring or loose connections can cause overheating in the wiring, resulting in inaccurate readings. Power fluctuations in damaged wiring can also cause the microchips in the thermostat or the HVAC’s control unit to produce errors. Corrosion can also lead to problems, especially on older thermostats.
Some thermostats will detect these issues and alert you. If you have a smart thermostat, you may even get a phone alert. Any thermostat with even a simple digital display should at least display an error code. However, serious damage may lead to operational issues or even cause the display to flicker or fail. In the most extreme cases, the thermostat loses its connection to the HVAC control unit, causing it to cease sending any updates on temperature settings.
Software Issues
Newer programmable and smart thermostats rely on software. A software update could fail and cause problems. Power outages can also damage the chips in the thermostat. If updating the software does not correct the problem, replacing the thermostat is usually the best choice.
HVAC Problems
Our technicians will make every effort to rule out other causes before we assume the HVAC might have an issue. However, a failing control unit may not communicate properly with the thermostat. This can lead to misreadings and power fluctuations.
A failing HVAC system can also cause problems that appear as thermostat misreadings. If the system is short-cycling, the home may never have time to reach the target temperature.
Rely on Our Expert Technicians
Swiss Air Heating & Cooling, LLC has been in operation since 1989 and is a family-owned business. You can rely on us because we have an A+ BBB rating and are fully licensed. Customers have left us many five-star reviews online as well. In addition to repairing and replacing thermostats, we offer heating and AC installation, repair, and maintenance services for all types of systems.
If your O’Fallon, MO home is having problems with thermostat readings, contact Swiss Air Heating & Cooling, LLC right away.
