Keystone KSTAT12-1C Air Conditioner 2020

Last Updated: April 2, 2020

Stuck in circles on the air conditioner market? Check out our review of the Keystone KSTAT12-1C through-the-wall air conditioner, where we may just have the answer for you.

by AC Rated

Today our team reviews the remarkable Keystone KSTAT12-1C, a unique through-the-wall air conditioner capable of providing a number of functions to the user, and doing so to a high level of efficiency, with the necessary certifications to back it up. However, this unit is not without its faults, check out our full review below and see if the Keystone KSTAT12-1C has been the unit you’ve been looking for all along.


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Keystone KSTAT12-1C Air Conditioner


Cooling Performance

With a cooling output of up to 12,000 BTUs, the Keystone KSTAT12-1C can comfortably service residential spaces of up to 550 square feet. Additionally, this unit will remove up to 2.5 pints of excess moisture from the air each hour, allowing the unit to double as an effective home dehumidifier.


Efficiency & Certifications

The Energy Efficiency Ratio (EER) of a unit takes into account its energy consumption, and its performance output. The figure that we obtain through examining an air conditioner in this way provides an accurate measurement of how efficiently a unit may be expected to function. Simply put, the higher the figure, the better. With the industry’s average EER currently standing at 9.7, any unit that scores above 10 is generally considered to be highly efficient. Therefore, by scoring an EER of 10.5, the Keystone KSTAT12-1C earns its position as one of the more efficient through-the-wall units on the market. Therefore, it should come as no surprise that the Keystone KSTAT12-1C comes Energy Star certified, which means that this unit’s performance efficiency adheres to a set of strict guidelines set out by the Environmental Protection Agency. In addition to this prestigious certification, this unit also benefits from a UL-listing, which essentially means that the air conditioner has been safety assessed by industry experts at Underwriters Laboratories.



With an LCD wireless remote control, the user is enabled to issue commands to their device from anywhere in the room, such as selecting from the unit’s 3 differing cooling speeds, and 3 fan speeds. Alternatively, the unit can be set to auto mode, which will detect when temperatures in the room reach uncomfortable levels and automatically boot up to re-establish a comfortable environment. Other functions include sleep mode, which allows the unit to function at decreasing capacities through the night, saving energy whilst maintaining comfortable conditions, and energy saver mode, which essentially just powers the unit off at periodic intervals to cut costs on bills. Finally, this unit also benefits from the inclusion of a programmable 24-hour timer, and auto restart capability. The programmable timer allows the user to input a schedule of operation into their Keystone KSTAT12-1C, so that it may function around your personal daily routine, whereas the auto restart function simply means that this unit will automatically reboot itself following a power outage, and resume functioning as usual.



Weighing approximately 75.9lbs, this unit is actually quite heavy when compared to other through-the-wall units on the market, especially when you take into consideration that its shipping weight stands at 131.1lbs. Regarding noise pollution, the Keystone KSTAT12-1C will register at a decibel rating of 56.5dB, which is slightly below the average human conversation, which generally registers at 60dB. This means that this unit will not intrude on your day-to-day life with obnoxious noise, unless you are in close proximity to the device. Another exceptionally useful feature of this unit is its extra-long 7 ft. power cord. Longer than most, this unit’s power cord allows for a greater range of potential set-up / install locations in the average family home. Finally, this unit has an easily cleaned slide-out mesh filter, with a filter alert indicator to notify the user when the filter requires cleaning. It is strongly advised that you keep your filter clean as a dirty filter may affect the product’s efficiency and performance.

Dimensions (Inches)

Height: 14.5″

Width: 24.2″

Depth: 20.3″


Help & Support

The Keystone KSTAT12-1C benefits from a 1-year parts and labor limited warranty, with an additional 4-years sealed-system coverage. Unfortunately, our team was unable to uncover any other support details at the time of this review.



The Keystone KSTAT12-1C excels in a number of categories. With a wide range of convenient features, high performance figures, and high efficiency figures to match, you cannot go wrong with this exceptional unit. Unfortunately, we were unable to find any online support resources, however, should you encounter an issue with your unit our recommendation is to contact the supplier that you purchased the unit from directly.