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If you have children, you’ve probably had to turn the thermostat down a notch after they set the temperature all the way up in winter. If you run an office, you must’ve encountered the same problem with your employees. A lock box can put a stop to that and keep the temperature exactly where you set it.

Benefits of thermostat lock boxes and covers

1. Prevent unwanted changes to heating or cooling settings

Having a lock box for your thermostat comes with many benefits you probably never even thought of before. For starters, it can help you prevent unwanted changes to the heating or cooling settings you’ve programmed. 

It is not uncommon for children to play with thermostats or change the settings because they’re too cold and refuse to put a sweater on. Avoid anybody tampering with the thermostat and keep the temperature that is most comfortable for you!

2. Save money!

If you run a store, office, gym, or any other business with a physical location, a lock box will help you save money. Don’t let your employees, colleagues, and customers change the settings on the thermostat. You can cut your heating bill by setting the appropriate temperature and not letting anyone turn the heat up higher or blast the air conditioning all day long. 

That works at home as well! If your kids want a change of temperature, they’ll just have to put on a sweater!

3. Landlords and Tenants or AirBnB

If you’re renting out an apartment or a whole building, you know the struggle your HVAC system goes through when the tenant keeps turning the AC on and off to make it cool down faster. This can contribute to the wear and tear of your HVAC.

Putting a lock box on a thermostat is not always legal, so you need to find out where you stand. However, once you’ve gained more control over the thermostat, you can prolong the life of your HVAC system!

A secure thermostat guard

The Honeywell Home CG511A1000 Medium is a great way to keep your thermostat away from kids.

Top Features
  • The guard protects the thermostat from unwanted changes and tampering.
  • The casing of the Honeywell guard is chemical and UV-resistant.
  • The guard comes with a universal key that can be used to open the heavy duty lock.

Do you have kids? If someone is messing with your thermostat settings, you can stop it in one simple step. All you need to do is get a guard that will prevent tampering.

The Honeywell Home CG511A1000 model is an excellent choice for those who have a thermostat that matches the maximum dimensions. The product is made from plastic that is resistant to yellowing, so it will serve you for a long time. The lockbox comes with a trustworthy lock and a key that you can hide from your children. They won’t have access to the thermostat without it!

The casing is also UV-resistant, which means it won’t be damaged by sunlight in summer. The guard is quite easy to install; all you need to do is mount it on the wall with 4 screws. You don’t need to remove the thermostat either. 

Before you settle on this lock box from Honeywell, make sure it will fit over your thermostat. The product description states that this guard will fit on all medium-sized thermostats of 6W x 5H x 1.75D inches or smaller.

What I liked
  • The lock box offers nearly effortless installation that you can complete by yourself.
  • The clear plastic casing doesn’t go yellow over time, so you can use it for years.
  • You don’t need to remove the thermostat from the wall to install this guard.
What I didn't like
  • The lock box does not fit all thermostats. It only fits medium-sized thermostats (6W x 5H x 1.75D inches or smaller).
  • The lock box does not come with installation instructions

The elago Lock for Nest Thermostats will keep the schedule on your Nest thermostat set while adding a line of defence if your home gets burgled.

Top Features
  • This lock is compatible with Google Nest 1/2/3 Generation and Thermostat E.
  • This lock box protects your thermostat from being tampered with and reduces risk of being stolen.
  • The display of the thermostat remains visible even when the lock is on.

The elago Lock for Nest Thermostat is compatible with the Google Nest Thermostat and Thermostat E. The stylish lock fits right on the thermostat without covering the display or changing the shape of the device. Most importantly, the lock doesn’t interrupt the sensors on the thermostat. 

The lock can not only protect your smart thermostat from children, tenants, and employees, but it is also helpful against theft. You can make sure your thermostat will stay in place and nobody will be able to change the settings. The only way to change the temperature when the lock is on is to do so through the official app using your phone or tablet. 

Installing the protector shouldn’t take you longer than a couple of minutes. All you have to do is slip the cover on the thermostat and you’re set! Keep in mind that the thermostat lock has a very specific shape for a reason. The lock was developed specifically for Nest Thermostats. It won’t fit on any other thermostat you might have at home.

What I liked
  • The lock does not interrupt the sensors on the thermostat, so the device can keep working as per usual.
  • The lock offers very easy installation. Just slip it on the thermostat and you’re good to go!
  • The lock doesn’t change the design of the thermostat. It is almost undetectable, as the shape is the same.
What I didn't like
  • There have been some complaints that the latching mechanism of the lock is not strong enough.

Other Thermostat / AC Lock Boxes

Top Features
  • The Braeburn 5970 model is virtually one-size-fits-all. The guard fits over most standard-sized thermostats.
  • The tamper-resistant design prevents unauthorized use. Nobody can get in and change the settings without a key.
  • The clear plastic is a strong and durable solution. It won’t take away from the design of the thermostat.

The Braeburn 5970 Universal Thermostat Guard is a universal guard that will fit over most standard thermostats. It is an excellent solution that will help you protect your thermostat from tenants, kids, or employees. The set comes with 2 keys. 

The guard comes in a clear, plastic design. The plastic is strong and durable, and the guard will leave the thermostat visible.

Top Features
  • The guard fits all Honeywell thermostats and most thermostats from other brands too.
  • The plastic cover doesn’t go yellow over time. It is also resistant to UV light.
  • It helps you keep the settings that you’ve programmed into the thermostat. Nobody can get in without a key.

This is another excellent option from Honeywell. If you’re planning on buying a Honeywell thermostat, there is no reason to look any further! This universal guard fits over all Honeywell thermostats. 

The plastic won’t go yellow over time and it’s resistant to UV-light, so it won’t get sun damage. Keep your thermostat safe from everyone!

Top Features
  • The Honeywell Home CG510A1019/N Thermostat Guard comes in the form of a clear plastic cover.
  • The thermostat guard comes with a built-in lock and a matching set of keys.
  • The guard fits the following models: CT87, CT3x without the wall plate, and the RTH5100B.

The Honeywell Home CG510A1019/N Thermostat Guard is another option from the well-known brand Honeywell. This guard only fits some thermostats, such as CT87, CT3x, and the RTH5100B. It can fit other models of similar size too. Make sure your thermostat fits the criteria before you purchase this guard!

Top Features
  • This thermostat guard is designed specifically for Emerson thermostats and ideal in the home or if commercials installed in restaurants, offices, churches, and other public places.
  • The thermostat guard comes in 2 sizes, small and large. It also comes with an in-built lock and a key.
  • The clear plastic guard will help you prevent personnel from adjusting the temperature without you.

Here is the Emerson G10 Universal Locking Thermostat Guard to change things up! This thermostat guard is designed specifically for offices and other public spaces. Customers are advised to use it to stay in control of the temperature even when they’re not in the office. The guard comes with a lock and a key.

Top Features
  • This thermostat guard claims to fit all thermostats while tailored for the Lux thermostat. Its dimensions are 9.5 X 5.75 X 4 – inches.
  • The thermostat guard is made from strong durable plastic
  • The Lux thermostat guard comes with an in-built lock and a key.

The Lux BB3001-004 Large Locking Thermostat Guard is made from clear plastic. The material is very strong and durable. It will limit unwanted access and keep people out of the thermostat. 

The set comes with one key and an in-built lock. This guard should fit all thermostats.

Should I Buy a Thermostat / AC Lock Box?

Tamper Proof

Make sure to see how durable the material of the lock box is before you buy it. As you already know, some are easier to tamper with than others. Thick, strong, durable plastic is what you should be on the lookout for! 

Another feature that will help you keep people out of your thermostat is the lock. Is there a lock? How reliable is this lock? Not to state the obvious but a proper built-in lock shouldn’t open for anyone who doesn’t have a key!

Universal Key

A universal key can come in handy if you’re handling more than one thermostat lock box. If you’re renting a building or are in charge of an office, you will probably have a couple thermostats to look after. If that’s the case, it helps to have a universal key that will open all the guards.

If you’re buying a guard for home, then the type of key doesn’t really matter, as you’ll only need one.

Easy Installation

Ease of installation is always an important factor to consider in home improvement projects. Most guards in this article are easy to install. However, check to see if you need to remove the thermostat to install the guard. Find out if there are instructions online for installing the lock box of your choosing. Some thermostat guards come with instructions, which is quite helpful.

You shouldn’t have a problem handling any of the locks mentioned above!

Dimensions are Crucial

You can buy the nicest thermostat lock box and it will be completely useless if it doesn’t fit the thermostat you have. Always pay attention to the dimensions of the product. Many claim to be one-size-fits-all, but that’s not always the case. 

Luckily, you can always find the dimensions of the guard in the product description online. Measure your thermostat to be sure and order the one that fits. Pay extra attention to this feature if your thermostat has an odd shape.

The Verdict

So there you have it. You now have a defence to keep those pesky kids from your thermostat! Our top pick is the Honeywell Home CG511A1000 Medium while the elago Lock for Nest Thermostat is a good option if you are looking to secure your expensive Nest thermostat from possible burglary.

A secure thermostat guard

The Honeywell Home CG511A1000 Medium is a great way to keep your thermostat away from kids.

Top Features
  • The guard protects the thermostat from unwanted changes and tampering.
  • The casing of the Honeywell guard is chemical and UV-resistant.
  • The guard comes with a universal key that can be used to open the heavy duty lock.


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