Keystone KSTAW05B Air Conditioner Review

Last Updated: April 2, 2020

Our team put the Keystone KSTAW05B to the test in order to see how it performs when compared to other units of its class. We found the plethora of convenient features to be a welcoming surprise, however we found the lack of customer service resources a little worrying. So, is it worth the risk? Does […]

by AC Rated

Our team put the Keystone KSTAW05B to the test in order to see how it performs when compared to other units of its class. We found the plethora of convenient features to be a welcoming surprise, however we found the lack of customer service resources a little worrying. So, is it worth the risk? Does the Keystone KSTAW05B window air conditioner and its shockingly low price tag punch high enough above its weight? Well, read our full review below to see what we found.


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Keystone KSTAW05B Air Conditioner Review


Cooling Performance

With a relatively below-average cooling performance of 5,000 BTUs, the Keystone KSTAW05B may not be the right choice for you if you have a large living space that needs cooling. Servicing an area of up to 150 sq. ft., this unit is not designed to cool even medium sized rooms. However, as it retails at a price of approximately $170, we simply cannot complain. This units maximum airflow stands at 129 cubic feet per minute. As an added bonus, most air conditioners have dehumidifying effect on their surroundings, with this device removing up to 1.3 pints per hour from the air. This is not a large amount compare to most other units we have reviewed, however it bears repeating that this unit retails for a remarkably affordable price, and so we cannot fault it for being weaker than the far more expensive units.


Efficiency / Certifications

With an Energy Efficiency Ratio (EER) of 11.2, this little window-mount stands confidently over the industry average of 9.7. To put it simply, the higher the efficiency of a unit, the less you will inevitably have to pay to run it. Therefore, when a unit runs above industry average, you save money. Further, this unit also boasts an Energy Star Qualification, which states that it complies with set regulations regarding energy consumption, strengthening our confidence in this units efficiency.

On top of being quite efficient, this unit also promotes efficient use, with 3 built-in fan speeds, so the user can tailor the intensity of the units cooling performance, so that they only use the energy they need. Finally, this unit is UL-Listed, which guarantees that this unit will not have a harmful effect on the air of your living space, so you and your loved ones can take a deep breath and relax in the knowledge that your unit has been tested, and is safe.



The Keystone KSTA05B really shines when it comes to convenience. There are virtually no features that this unit lacks. Controllable via a wireless remote control, the user can sit back in ease, and change the settings of their unit from anywhere in the room.

A 24-hr programmable timer is also built-in to this device, allowing the user an even greater degree of control over how, and when their unit operates. This timer allows the user to input times when they would like their unit to function, effectively allocating the unit schedule to follow.

Auto mode allows the Keystone KSTAW05B to detect unfavourable temperatures in its immediate area, which will then provoke the appliance to power-on, and get to work regulating its environment.

A Fan Only mode will circulate air, while not providing cooling. Similarly, the Dehumidify Only mode will remove moisture, while not cooling the air.

Sleep Mode will allow the unit to gradually increase temperatures throughout the night, with the aim of saving you energy while you sleep, yet keeping the air at a comfortable temperature for sleep. An added benefit of this feature is that you needn’t worry about waking up to a cold home.

Energy Saver Mode does exactly as it says, and enables the device to function at reduced capacities in order to save you cash on your energy bills.

Finally, last but certainly not least, is the Auto Restart function, which will reboot the unit following a power outing. This is an essential function for those of us living in areas that suffer regular power outages due to natural disasters, infrastructural maintainance work, etc.

Maximum Window Kit Extension (Inches):

Width: 36

Height: 13



A built-in air filter prevents airborne particulates such as dust or hair from entering your living space. This is always an appreciated feature, as it allows the operator peace-of-mind while their unit is working.

Functioning at a noise level of 55dB, this unit is relatively quiet when compared to other units, and considering that the average human conversation registers at approximately 60dB, there are no complaints here about the noise the Keystone KSTAW05B creates.

Weighing only 40lbs, the Keystone KSTAW05B is also quite light when compared to most other window-mounts. However, if it proves too heavy to lift, we strongly urge our readers to seek help, especially during installation.

Unfortunately, this unit does lack directional air louvers, however this is a small price to pay for the sheer convenience of operating this unit.

Dimensions (inches):

Height: 12

Width: 16

Depth: 15 3/4


Help & Support

The Keystone KSTAW05B is backed by Keystone’s 1-year appliance warranty, and 5-years compressor warranty. For more information regarding Keystone terms & conditions, we advise contacting their representatives directly.

Unfortunately, we could not find any official Keystone website at the time of this review. Furthermore, it is unclear to us how to actually contact Keystone, as there does not seem to be any way of finding this information online. Therefore, by investing in a keystone product unfortunately you will have to place quite a lot of faith in the company.



This unit performs fantastically when it comes to convenience. While relatively weak when it comes to the force produced by this unit, we excuse this due to the low price-tag, which indicates that this unit was clearly designed for installation in a relatively small living space, which we believe it would suit.

However, we do take slight issue with there being a lack of keystone official website, as we at Air Conditioners Rated strongly believe in the importance of customer service in this industry. However, the good reviews of this product stand in its favour, therefore we do not believe there is anything to be worried about with relation to the lack of support infrastructure.

Overall, we enjoyed this device, and would recommend it for small living spaces.