After 60+ hours of research and reviewing, we can confidently say that the best thermostat lock box on the market right now is the Emerson F29-0222. This lock box is simple, standard for lock boxes, but the sturdy metal construction makes it reliable and recognizable. This is the regular beige-enamel metal lock box that we have all seen at one point or another. This box is vented correctly to make sure your thermostat works as it’s supposed to, without giving off a false reading due to a lack of airflow. All boxes from this model are keyed differently, which is another layer of safety. If you want a lock box that will keep your thermostat out of sight and discourage unwanted tampering, this is the box for you.
Honeywell CG511A1000 Medium Thermostat Guard
- Large casing
- Keys are universal for multiple purchases
- May easily be opened without the key
The Honeywell CG511A1000 Medium Thermostat Guard works well to prevent your thermostat from being tampered with unless your guests are persistent. The cover is large enough to be universal (though it will not fit all thermostats), so this is a good choice for pretty much anyone — whether you have an old-school thermostat or a smart WiFi thermostat. All boxes are keyed the same so if you order multiples, one key will open all of them. Some customers complain that the cover is not vented enough, which can lead to incorrect thermostat readings, but this can be solved by installing the cover with a small gap between the plastic and the wall. The cover is clear and allows you to easily read the thermostat.
Honeywell’s CG511A1000 Medium Thermostat Guard is great for your Airbnb rental because it is large, simply designed, and difficult to get into. Your guests will be able to see the thermostat, but they will not be able to change the settings. It is large enough to fit around an existing thermostat (and even a small smart thermostatp), but it looks good enough to fit into your modern décor as well.
We also considered StatGuardPlus’s Thermostat Guard for this category, but the shape and general aesthetics allowed the Honeywell option to win out.
Emerson F29-0198 Universal Locking Thermostat
- Easy to install
- Great dimensions for Emerson thermostats
- Does not come with plastic anchors for mounting
The Emerson F29-0198 Universal Locking Thermostat works great as a universal cover and for Emerson and White-Rodgers thermostats. It has a pretty universal size so it can be made to fit other thermostats. This locking thermostat is somewhat flimsy and easy to break open. There is only one key, which can be inconvenient if multiple people need to get into the thermostat. Overall, this is a great thermostat lock box.
We chose the Emerson F29-0222 Universal Thermostat Guard as the best overall thermostat lock box. Though it is not the fanciest (or more attractive) box on our list, it is sturdy enough, and we especially loved that not all the boxes are keyed the same. A standard and recognizable design with plenty of venting make this one of our favorite options.
We also considered the Honeywell CG511A1000 Medium Thermostat Guard for this category, but the sturdier construction of the Emerson F29-0222 won out.
Additionally, Emerson’s F29-0198 Universal Thermostat Guard is the perfect thermostat guard for commercial locations. This includes storefronts, office buildings, warehouses, and other public locations. This is also a plastic lock box, but it works universally with most medium-sized rectangular thermostats, so chances are it will fit on the one in your office.
The Bramec Heavy Duty Metal Thermostat Box was up for the winner of this category, but, in the end, the Emerson F29-0198 is nicer to look at.
Bramec Heavy Duty Metal Thermostat Box
- Sturdy and won’t open easily
- Easy to install
- Comes with one key
Bramec’s Heavy Duty Metal Thermostat Box is perfect for commercial use. There are plenty of venting holes in the cover, allowing airflow through to the thermostat inside. This can result in truer readings and will allow your thermostat to properly heat or cool your home. It is sturdy enough that it doesn’t open easily, and keeping your thermostat hidden from prying eyes may be a good idea for office buildings or warehouses. The single key is useful, but you will have to purchase additional keys directly from the manufacturer if you need them.
The best quality thermostat lock box on our list was the Bramec Heavy Duty Metal Thermostat Box. This box is heavy and secure, making sure that no one can get to your thermostat unless you want them to. It won’t open easily (and is sometimes difficult to open even with the key). Overall, it’s a great lock box and certainly of the highest-quality materials on our list.
We also considered Braeburn’s 5970 Universal Thermostat Box for this category, but the metal construction of the Bramec Heavy Duty Metal Thermostat Box put it in the first place.
Braeburn 5970 Universal Thermostat Box
- Unique shape
- Optional back plate
- Does not have a hinge
The Braeburn 5970 Universal Thermostat Box can be installed around any thermostat that fits the dimensions, and it is large enough that even rounded models will easily fit inside. This box can be installed with a ring base, or you can use the included wall plate to make it that much more secure. There are two keys included, so you won’t run into any issues that similar lock boxes. The design is well-ventilated and works to prevent tampering – both with the box itself and with the thermostat inside.
StatGuardPlus Thermostat Guard
- Unique locking mechanism
- Easy to install
- Combination wheels can sometimes get stuck
This StatGuardPlus Thermostat Guard is made of heavy-duty material and won’t yellow or cloud up. The clear version is just one of the options that you have – this lock box is also available in both white and brushed nickel. Both of these latter options are opaque, so you will not be able to see the thermostat (and neither will your guests). The combination code is three digits and can be reset as needed, so there is no need to purchase additional keys. Plus, it’s simple to install and has all of the proper vents to keep your thermostat working well.
Lux BB2001-005 Medium Locking Thermostat
- Affordable and easy to install
- No hinge
Lux’s BB2001-005 Medium Thermostat is the mid-range model from this company; there is a smaller cover and a larger one, so there is a size to fit every thermostat. This cover installs easily and is very sturdy. It doesn’t have a hinge, so the only way to adjust the thermostat is to take the cover off, which can be a bit troublesome. The vents are nice, but they are also large, which may allow people to shimmy small objects into the vents and change the buttons on your thermostat. That is definitely something to consider before you make this purchase.
Honeywell CG510A Small Thermostat Guard
- Can be used with or without the wall plate
- Durable and easy to use and install
- Only one key
The Honeywell CG510A Thermostat Guard is perfect for Honeywell thermostats in models CT87, CT30, CT31, and CT33, as well as the RTH5100B model. It is made of clear, sturdy plastic and locks on the bottom, so it’s more difficult for someone to get into. It doesn’t have a hinge, but it is easy to install around your existing thermostat and is well ventilated near the wall. It’s a perfect cover for these specific thermostat models. Being able to see your thermostat makes this perfect for residential settings, rentals, and other non-commercial properties.
White-Rodgers G20 Thermostat Guard
- Perfect for rectangular thermostats
- Deep for larger thermostats
- Can’t make extra keys
While the White-Rodgers G20 Thermostat Guard is meant to be used with thermostats from this brand, but it can be used by any thermostat that fits inside. It’s especially perfect for smaller, rectangular thermostats that need a deep lock box. Some people complain that it is easy to remove if you wiggle it in the right way, so keep that in mind. Otherwise, it comes with a singular key and additional keys must be purchased from the manufacturer. All G20 lock boxes are keyed the same.
Supco BTG-RK Thermostat Guard
- Colored plastic design
- Fits securely over a variety of thermostats
- Single key
- Installation may be more difficult
Supco’s BTG-RK Thermostat Guard installs with a base plate behind the thermostat, so installation can be a bit difficult. You may need professional help if you are not handy. It comes with a single key, but the design is simple, unique, and well-ventilated. Because of the base plate, it can even install without making new holes in your walls, which is definitely an advantage it has over ring base installations. It’s also sturdier and often harder to open without the key if it is installed with a solid base.
Supco’s BTG-RK Thermostat Guard is the best value on our list. This is a simple lock box that allows you to protect your thermostat at an affordable price. It does its job well. It will not be easy for anyone who doesn’t have a key to get into this lock box.
We also considered the TayMac ZTC100 Thermostat Cover for this category, but the option to include a solid base installation for the Supco BTG-RK Thermostat Guard put it in the lead.
TayMac ZTC100 Thermostat Cover
- Patented hinge
- Easy installation
- Can be mounted in any direction
- No spare keys available (at all)
TayMac’s ZTC100 Thermostat Cover is unique even on this list. It has a patented internal hinge that is rotatable, so you are able to open the lock box from any angle that you’d like. This is because you can install the box in any direction. If you want to put the lock on the top or on any of the sides, you can do that. However, there is no way to purchase additional keys and you cannot have any cut from key blanks, so you will only ever be able to get two keys to the box. This lock box also ships with a removable base plate.
PRO1 1AQ T150 Thermostat Guard
- A perfect fit for the corresponding thermostat
- Also fits similar small thermostats
- Can be difficult to install
- Standard design
The PRO1 1AQ T150 Thermostat is perfect for all PRO1 thermostats and other thermostats of a similar size. It’s small enough to fit snug around the smallest thermostats, which is definitely useful, as these lock boxes tend to run towards the larger side. There is a ton of ventilation around the sides, and it comes with two keys. Sometimes the installation can be a bit difficult, as it takes some fiddling to get the cover to fit correctly. However, once it is mounted, it is not easy to get off without the key.
Safety Technology International STI-9110 Thermostat Protector
- Rounded front surface
- Vents are arranged in a double layer
- Bulky and large
The Safety Technology International STI-9110 Thermostat Protector is great for areas where you have a lot of extra space. It has a unique convex design that looks great, but it does stick out from the wall a fair bit. It is well-ventilated, and the vents are arranged in a double layer around the base, so it is not easy to tamper with it. Some people have had issues getting the lock holes to line up properly, and it can be a bit difficult to seat. However, outside of those concerns, it works well.
Emerson F29-0222 Universal Thermostat Guard
- Beautiful enamel finish
- Heavy-duty materials
- Not entirely tamperproof
Emerson’s F29-0222 Universal Thermostat Guard is perfect for commercial locations and spaces where your thermostat doesn’t need to be visible. There is venting all around the face of the box and the sides, so there is always enough airflow to keep your thermostat reading accurately. However, unless it is installed flawlessly, it will be easy to tamper with and bend the locking mechanism. If installed the right way, it’s heavy-duty and not easy to get into without the key. Each box comes with only one key, and the keys are not universal; not every lock box is keyed the same, which is important if you are ordered multiples for the same building.
Bramec Clear Plastic Thermostat Guard
- Simple and easy to install
- Can purchase with either mounting type
- Venting holes are unusually large
Bramec’s Clear Plastic Thermostat Guard is a simple lock box that is great for use in rentals or in your home. However, the venting holes are on the larger side, making it easy to worm some sort of wire into the box to change the thermostat settings. It is a standard size that will fit a large variety of rectangular thermostats, and you have the option of choosing a ring base mount or a solid base mount. This lock box gets the job done affordably, and it is fairly standard as thermostat lock boxes go.
Do You Even Need a Thermostat Lock Box?
Thermostat lock boxes can be useful, but their application has narrowed over the past few years. Most smart thermostats come with locking mechanisms already, so getting a lock box to go over them would seem like overkill, and a hassle to install besides.
There is also a bit of a stigma that comes with using a thermostat lock box for a rental property such as an Airbnb or hotel. With an Airbnb specifically, the use of a lock box may be a negative deterrent for guests, as it sends out a message that you don’t really trust them (and they might not like that they can’t adjust the temperature to their liking).
While these lock boxes can be effective, they can also seem miserly or crude to guests, so keep that in mind if you plan on purchasing one for this purpose.
It might seem like overkill to use these in your home as well, even if your family can’t seem to stop raising and lowering the temperature. In any setting except perhaps commercial (such as a school, office building, or hospital), the boxes seem rather dramatic to some.
Consider whether you actually need a lock box or if you’d be better off settling a thermostat dispute in another way.
In a hurry? Here are some of the most important things to take into consideration when choosing a thermostat lock box.
- Always look for a lock box that fits your specific thermostat model before choosing a universal box.
- If you must choose a universal box, keep a close eye on the interior dimensions to ensure a good fit.
- Choose a plastic box with a ring base for use in your home or another residential setting.
- For commercial settings, a metal box or a plastic lock box with a solid base can be your best option.
Thermostat Lock Box Features and Options
While thermostat lock boxes are fairly standard across the board, there are a few features that you need to watch out for. When you need to make sure the temperature stays constant in your rental, business, or even in your home, make sure you consider these features.
Options: Polycarbonate, Metal, Plastic
The material that the thermostat lock box is made of can determine how long it will last, as well as how secure your thermostat will be. The material can also determine the price of the thermostat cover (as, naturally, metal covers will be more expensive and clear plastic covers will be less so).
Plastic is the most common material used for these covers. While it is sturdy and clear so you can see the thermostat without removing the cover, these types of covers can also be the lowest quality. They can cloud up easily and might yellow over time.
Polycarbonate covers are clear like plastic covers, but they are a bit sturdier and long-lasting. However, it is rare to find specifically polycarbonate lock boxes; most are plastic.
Metal lock boxes are a popular category as well, though they are getting rarer. Metal lock boxes are not clear, so you cannot see the thermostat when they are installed. However, they are the sturdiest option available. These types of boxes can be especially useful in commercial locations where the temperature doesn’t need to be displayed to the public.
The interior dimensions of the lock box refer to the size on the inside of the casing. Why is this important? Because not all lock boxes are made to fit specific thermostat models. Some are universal, and will be able to fit over any thermostat that can be placed inside.
It’s important that you know the dimensions of your thermostat before ordering, and then use the internal dimensions measurement to figure out if the cover is going to fit. This is a more accurate way to find out if the cover will fit than using the product dimensions overall.
Alternatively, the product dimensions refer to the exterior size of the thermostat lock box. This is not the measurement to use if you are trying to determine if your current thermostat is going to fit. Instead, this measurement can be used to determine how large the installation will be, how far the box is going to stick out from your wall, and considerations towards your home decor or commercial design.
This can also be important when considering lock boxes with a solid base, as we will discuss below.
Options: Ring base, Solid base
The installation method will tell you how easy it is to put the box onto your thermostat and if you’re going to need to remove your thermostat first.
A ring base thermostat lock box will install right over your existing thermostat. There is no need to remove the thermostat and re-install it with the box over it. This is the easiest type of thermostat lock box to install, and will not require professional help in most cases.
A solid base installation is sturdier and recommended for more commercial areas. However, installing one of these boxes will require you to remove the thermostat from the wall and reinstall it with the box placed over it. This type of lock box installation might require a professional electrician.
Typically, the distinction is fairly easy: if you have an existing thermostat, choose a lock box with a ring base installation. If you are purchasing a new thermostat, choose a lock box with a solid base installation for greater security.
Options: Key Lock, Combination lock
There are generally two different types of locks that thermostat lock boxes use. Most boxes use a key lock, and combination locks are rarer.
A key lock, of course, uses a key to make sure that no one can tamper with the thermostat. Some locking thermostat guards use a standard key while others use a rounded key style that is more difficult to pick. Rest assured, any key lock will do the job; most people aren’t going to be dedicated enough to pick the lock on your thermostat lock box.
Combination locks are rarer, but some believe that they are more secure. It also means that you don’t have to keep track of the key, and not just anyone will be able to open it.
Chemically resistant lock boxes won’t degrade over time due to exposure to cleaning chemicals, cigarette smoke, or other chemicals. This feature can be incredibly useful in commercial locations such as warehouses and other industrial settings.
UV Resistance is important when the lock box is going to be exposed to the sun. If it’s located in a sunny room or will be getting any type of direct sunlight, you want to make sure that it isn’t going to wear down.
The sun can do all sorts of damage to plastics and other materials that are exposed to it constantly. When it comes to lock boxes, the sun is often responsible for fading, clouding, or yellowing of the cover. This can make it difficult to see the thermostat inside and unpleasant to look at overall.
The weight of the lock box can be important for installation. While most thermostat lock boxes are made to hang on a wall and therefore won’t be very heavy, some walls might not be able to handle the heavier ones. Keep this in mind if you are installing the lock box in a location with paneling or drywall. Some of the heavier boxes might pull themselves away from the wall if they are heavier.
Some lock boxes can be used on just about any thermostat that will fit inside. These lock boxes are described as ‘universal’ because they are not made to cover a specific thermostat model and can be used on a variety of makes and models.
A warranty is an important feature to consider when purchasing any product, not just a thermostat lock box. This is something like an assurance of quality. Most companies will replace or refund a product that does not work correctly, or a product that breaks during normal use due to a manufacturing error.
Any product that has a warranty is always preferable to one that doesn’t. It’s better to have a warranty and not need to activate it than to have a product break and be unable to get a replacement.
Where Is The Lock Box Going to be Installed?
You already know that thermostat lock boxes can be useful in schools, hospitals, hotels, Airbnb properties, and more. But you may also want to consider where you need the lock box to be installed before you make your final choice.
If you need the cover for a thermostat located in a school, office building, or other public space, consider purchasing a metal lock box. These boxes are not clear and hide the thermostat inside. In these settings, no one needs to see the temperature and settings, and someone on the property (such as the principal, shift manager, or another authority figure) can hold the key. For this setting, choosing a model that uses a key to open is easiest.
However, in a hotel or Airbnb situation where a tenant or guest messing with the thermostat could be costing you a lot of money, it’s fine to use a clear thermostat lock box. It might seem more positive to your guest that you aren’t trying to hide it away. In these situations, the type of lock doesn’t really matter.
Knowing where you’ll be using the lock box is important in your choice.
What Thermostat Model Do You Have?
If you have a popular thermostat (such as one made by the Honeywell brand), there might be specific lock boxes for each model. This means that you can search for a lock box that fits your thermostat perfectly without worrying about dimensions or fit. You may need to stop by your home improvement store for help with fitting your lock box.
It’s always a good idea to check for a specifically-made thermostat lock box before searching for a universal one. If a lock box isn’t available for your specific type of thermostat, then you should consider the interior dimensions of a universal lock box.