How To Tell If You Need A New Thermostat

It’s easy to neglect your thermostat and think that it’ll last forever. However, like every other part of an HVAC system, the thermostat will eventually wear out. You’re not alone if you’ve ever struggled with how to tell if you need a new thermostat.

Replace your thermostat if it’s over 10-15 years old and no longer runs efficiently. You can tell you need a new thermostat if your bills have increased despite a poor performance. It’s also worth replacing your thermostat if nothing happens when you adjust it, despite having fresh batteries. Physical trauma and excessive humidity can also ruin a thermostat.

Never repair a thermostat if it’s almost 15 years old, as that’s a waste of money. Instead, put that money toward buying a new one. Follow along as we explore how to tell if you need a new thermostat.

When To Replace Your Thermostat

1. Your AC Or Furnace Short Cycles

Short-cycling is one of the most common HVAC problems, and it may relate to your thermostat. This refers to when your air conditioner or furnace runs briefly, shuts off, runs, then shuts off again. The cycle can continually indefinitely until you fix the problem.

Short-cycling can happen because of problems like a dirty air filter, clogged ductwork, and a bad flame sensor. However, it’s especially common with faulty furnaces, especially if there’s a problem with the wires or batteries. For example, thermostat wires can wear down due to poor installation, corrosion, and physical trauma.

If the thermostat is 10 years old and needs to be rewired, it may be worth replacing it altogether. Put the money that it would cost to rewire it toward a new thermostat. Otherwise, you may only enjoy your rewired thermostat for 3-5 years before you must replace it. 

2. False Readings

False temperature readings are common with a faulty thermostat. This is usually the first sign that something is wrong. For example, you may know that the room is cold, but the reading on the thermostat is 70 degrees Fahrenheit.

You can check this by putting a thermometer in the room to see if it matches the thermostat. False readings typically occur due to problems with the sensors and other key components. This typically only happens with an older thermostat, as it goes through lots of wear and tear.

Thermostats can even suffer damage due to excessive sunlight exposure over the years. Direct sunlight can damage a thermostat and cause false readings. When replacing the thermostat, you should mention that you don’t want it located in direct sunlight.

3. Random Temperature Changes

Everyone expects a thermostat to stay at the temperatures they at set to. After all, that’s the point of having a thermostat in the first place. That said, a thermostat may randomly adjust the temperature throughout the day if it’s past its prime.

This is especially common for thermostats that are 10 to 15 years old, which is the standard working lifespan. Not only is this problem annoying, but it can also take a big toll on your energy bills. That’s essentially true during winter, when your furnace usage affects gas and power bills. Pay attention to the thermostat and how the HVAC system reacts to it. If the temperature randomly changes, it’s worth calling an HVAC technician. Depending on how old it is and what shape it’s in, they may recommend replacing the thermostat.

4. Nothing Happens When You Adjust The Thermostat

You probably expect your furnace to run when you raise the temperature on your thermostat. However, that may not necessarily happen if it's faulty and beyond repair. This should happen instantly, so you can tell something is wrong right away. The best-case scenario is that the batteries are dead or the circuit breaker tripped. These are easy fixes, but they won’t work if the thermostat is faulty. You may be able to calibrate the thermostat, but you must get a new unit if that fails.

5. Exorbitant Bills

Summer and winter bring high energy bills, which nobody looks forward to. This is normal, as people rely on an HVAC system much more when it’s cold or hot outside. However, there’s a limit to how high your bills should be before you realize something is wrong.

That’s especially true if you know your AC and furnace are in great shape, but your bills are still high. This should at least make you feel suspicious about the thermostat, which may be the root of the problem. High bills go hand-in-hand with faulty temperature readings and short-cycling.

Hire an HVAC technician to inspect the thermostat and replace it as needed. There’s a good chance that replacing the thermostat will help you save a fortune on bills.

6. The Thermostat Sits In The Sunlight

Thermostat placement is more important than you may think, as it affects performance and longevity. For example, thermostats that sit in the sunlight are more likely to have inaccurate temperature readings. The sensor will detect extra heat due to the direct beam of sunlight, and will make your AC run more often.

Conversely, your furnace may not run soon enough when your house is cold, as the sunlight will trick its sensor. Prolonged sunlight exposure can also overheat a thermostat and damage the internal components.

Moving the thermostat can fix the problem if it’s relatively new and in great shape. If the thermostat has already sat in the sunlight for years, it may be beyond repair at this point.

7. It’s Gone Through Physical Trauma

Like anything else in your house, a thermostat can go through lots of physical trauma. Dropping or bumping into a thermostat can damage the casing and the unit’s internal components. Even dirt and dust can get stuck inside a thermostat and cause serious damage that can’t be fixed.

Humidity is another threat to a thermostat that many people don’t necessarily think about. Excessive indoor humidity can contribute to corrosion, which affects the wiring and hardware. High humidity can also make an HVAC system run longer and affect the indoor air quality.

8. Your Thermostat Is 10-15 Years Old

Thermostats are quite durable in that they last up to 15 years. However, the performance typically takes a nose dive in the last 5 years, and it becomes quite noticeable. Some people even replace a thermostats after just 10 years, which is sometimes necessary.

For example, your 10-year-old thermostat may have several faulty components, and replacing them may be expensive. In that case, it’s not always worth spending the money on repairs, which can cost hundreds of dollars. You’d be much better off saving that money and putting it toward a new thermostat.

Are Smart Thermostats Worth It?

It’s worth upgrading to a smart thermostat for many reasons, including energy savings. You can save at least 8% on your yearly energy bills, or up to 20% in some cases. That’s because a smart thermostat can monitor your home and adjust itself to ensure you don’t cool or heat an empty house.

You can also program a smart thermostat to run on a schedule based on when you’re home. That way, you can save money on heating and cooling while you’re at work or on vacation. In many cases, you can also remotely control your smart thermostat via a mobile app. This lets you set your house to heat shortly before you get home, so you don’t walk into a cold house. The energy savings, convenience, and comfort of a smart thermostat are worth it.

Should You Replace Your Thermostat At the Same Time As Your Furnace?

You don’t need to replace your thermostat at the same time as your furnace in every case. For example, there’s no need to replace the thermostat if it’s a few years old, even when you replace a furnace. An electrician can easily wire your thermostat to power your new furnace.

However, it’s worth replacing a thermostat if it’s as old as the furnace you’re replacing. In that case, they’re both probably old and past their prime, so replacing both is a good idea. However, you should always replace your thermostat if it’s incompatible with a new furnace.

Summing It Up

It’s time to get a new thermostat if yours is 10 to 15 years old and needs repairs. If you repair your thermostat when it’s that old, you’ll need to replace it shortly after. Exorbitant bills, uneven cooling, and an inconsistent performance arr signs it’s time to replace your thermostat.

Related Guides:

• Common HVAC Mistakes To Avoid In The Winter
• Seven Tips To Help Your Furnace Work Better