Finishing close to the top of the group, the GLAS is a solid thermostat, but couldn't quite topple our top recommendations. It has a particularly sleek and stylish design that stands out from the rest, but we found the looks of this product to be very dependent on the type of walls you have and how clean it is — we found it to be a total magnet for dust and fingerprints. It does stand out by having a built-in set of air quality sensors and works with both Alexa and Cortana and is very accurate. Unfortunately, it is also one of the most expensive thermostats we have tested to date and its overall operation seemed a little buggy and less user-friendly than some of the top models. It might be a great bet if you absolutely love the look — and live somewhere with perfect walls, but otherwise, you are probably best served by another model.
Johnson Controls GLAS Review
Pros: Stylish, accurate
Cons: Very expensive, seemed a little buggy to us
Manufacturer: Johnson Controls
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Johnson Controls GLAS
$228.70 at Amazon
$249 at Amazon
$158.00 at Amazon
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|Pros||Stylish, accurate||Sleek, easy to install, accurate||Very accurate, subdued design, very easy to set up||Integrated Alexa voice assistant, easy to install||Easy to use, good remote access|
|Cons||Very expensive, seemed a little buggy to us||Expensive, support just refers you to a Nest Pro||Limited color options, display is harder to read||Lackluster performance in our accuracy tests, could be more intuitive to use||Expensive, inaccurate, voice control through the app is silly|
|Bottom Line||This expensive thermostat looks great but its performance left a bit to be desired||Best for the smart home, but may be underutilized in many homes||The Nest Thermostat E is a fantastic product for those that want most of the features of a premium product without paying a premium price||While the Ecobee SmartThermostat isn’t our all-time favorite thermostat, it is great for frequent Alexa users||The largest screen, and the easiest to use by far|
|Rating Categories||Johnson Controls...||Nest Learning...||Nest Thermostat E||SmartThermostat...||Honeywell Wi-Fi...|
|Ease Of Use (40%)|
|Install & Support (30%)|
|Remote Access (20%)|
|Specs||Johnson Controls...||Nest Learning...||Nest Thermostat E||SmartThermostat...||Honeywell Wi-Fi...|
|Colors||Transparent screen with silver base||Stainless Steel, Copper, White, Black, Mirror Black, Brass, Polished Steel||Frosted White||Black||Silver|
|Battery Backup||No||Built-in, rechargeable lithium-ion battery||Built-in, rechargeable lithium-ion battery||No||No|
|Learning/ Adaptive Controls||No||Yes - "Nest Sense"||Yes - "Nest Sense"||Yes - adaptive||Yes - "Smart Response Technology"|
|Dimensions||Height: 5 in
Width: 5.5 in
Depth: 1 in
|Diameter: 3.3 in
Depth: 1.21 in
|Diameter: 3.1 in
Depth: 1.14 in
|Height: 4.29 in
Width: 4.29 in
Depth: 1.00 in
|Height: 3-1/2 in
Width: 4-1/2 in
Depth: 7/8 in
|Works Directly with Alexa/Amazon Echo||Yes; Also built-in Cortana||Yes||Yes||Built-in||Yes|
|Works with Apple HomeKit||No||No||No||Yes||No|
|Model #||SIO2-10000||T3007ES||T4000ES||SmartThermostat with voice control||RTH9580WF|
Our Analysis and Test Results
This model finished right behind the Nest Thermostat E and the Nest Learning Thermostat. The GLAS is a bit harder to install, is slightly less accurate, and is a little bit harder to operate overall, but it is by far the most expensive.
In the two years or so that we have been testing and rating wifi smart thermostats, we have been continually refining our testing procedures and updating our review as new models have come out, buying them all to test and score. We split our testing procedure into four weighted testing metrics, with the GLAS' results shown below.
Ease of Use
Responsible for almost half of the total score at 40%, our Ease of Use metric has the most bearing on the overall score of each product. We looked at the difficulty in the initial setup and configuration process, how hard it is to set a schedule, adjust the temperature, time, or other advanced settings, as well as the clarity of the information displayed. The Johnson Controls GLAS did fairly well, earning a 6 out of 10 for its performance.
Once the thermostat is mounted to the wall, the initial configuration is nice and simple, with prompts that guide you through the whole process. The time and date set automatically when the device is connected to wifi, though you do need to set which time zone you are in. There aren't a ton of advanced settings to configure, but the single menu of additional settings is relatively easy to navigate and decently user-friendly.
It also is very easy to adjust the current temperature setpoint by tapping it and then using the arrow icons.
The scheduling is a little finicky, as you set the temperature for when you are home and away, then set what times you plan on being at home, rather than setting different temperatures for specific times.
The information displayed on the GLAS is clear and easy to read, with the option to adjust the brightness to maximize visibility for your home's lighting situation. However, the screen seems to be an absolute dust magnet and holds fingerprints very well, making relatively frequent cleaning a must.
If you are embracing the smart home side of this product, it can interface with both Microsoft's Cortana and Amazon's Alexa, though we did find Alexa to have a bit of an edge at the time of writing. This thermostat also has air quality sensors and can activate the fan according to their reading, as well as run some auxiliary appliances, such as a humidifier or dehumidifier.
Install & Support
Worth 30% of the total score for the GLAS, our next metric moved on to evaluating how much effort is required to physically install the thermostat and how helpful we found the customer support team to be when faced with our questions. The GLAS again scored well, earning a 7 out of 10 for its efforts.
We found the customer support to be quite helpful, even though it did take a few back-and-forths over email until we got some of our smart home issues ironed out. The standard installation process is quite pain-free with one exception and there are guided prompts in the app and on the thermostat to lead you through it.
The main difficulty with the installation of this thermostat is the lack of space. You have a much smaller space to work with, as the wiring is all done through the non-transparent part of the thermostat. This also means that this thermostat won't do the best job of hiding imperfections or damage from your old thermostat's mounting method, so some touch-up work may be required before installing the GLAS.
One of the nicest things about these products is the ability to adjust or check the temperature remotely — a great way to make sure your HVAC system is behaving while you are on vacation or make sure your home is the perfect temperature the moment you walk in the door. For this metric, we ranked and scored how easy it is to adjust the temperature or schedule using the mobile app, as well as the other types of adjustments you can make. It makes up 20% of the total score, with the GLAS again doing decently well, meriting a 6 out of 10.
The mobile app is very intuitive and easy to use — essentially an almost exact mirror of the interface on the thermostat itself. You can't make any equipment adjustments remotely, but you can update or reset the device. Additionally, some of the settings are even more consolidated on the mobile app, requiring you to navigate through fewer submenus to perform tasks like activating "Vacation" mode.
For the remaining 10% of the total score, we compared how accurate each thermostat measured the temperature, comparing them against a laboratory grade digital thermometer. The GLAS is one of the more accurate models we have tested, earning it an 8 out of 10.
This thermostat usually displayed a temperature that was within a single degree of our control, though we did notice larger discrepancies for a short period right after the thermostat was installed — these usually abated within a matter of hours.
This product is a terribly budget pick, being one of the most expensive we have seen and forcing you to pay a premium price for looks.
We were very excited about the prospects of this thermostat and ended up coming away disappointed. This device did quite well overall, but its excessively premium price doesn't quite mess with its second or third tier performance, precluding us from recommending it.
— David Wise and Austin Palmer