Acer K138ST Projector review: A decent LED home projector

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Techaeris Rated 8/10

Projectors have multiple use applications from the office to a home theater, and the Acer K138ST is capable of living in multiple worlds. With a strong LED lamp and a 1280×800 resolution, this projector should fall into just the right spot for some users seeking a decent machine. Keep reading for our full Acer K138ST review.

Estimated reading time: 6 minutes

Acer K138ST Specifications


  • Native Resolution: 1280 x 800
  • Maximum Resolution: 1920 x 1080
  • Standard Mode Brightness: 800 lm
  • Native Aspect Ratio: 16:10
  • Compatible Aspect Ratio: 16:9/4:3
  • Contrast Ratio: 100,000:1
  • Throw Ratio: 0.8:1
  • Digital Zoom: 1.7x
  • Vertical Keystone Correction: -20°/+20°
  • Maximum Vertical Sync: 120 Hz
  • Maximum Horizontal Sync: 100 kHz
  • Minimum Vertical Sync: 50 Hz
  • Minimum Horizontal Sync: 30 kHz
  • Color Supported: 1.07 Billion Colors (30-bit)

Projection Lens

  • Lens Type: Manual Focus
  • Maximum Lens Aperture: F/1.9
  • Maximum Focal Length: 8.02 mm
  • Minimum Diagonal Image Size: 25″
  • Maximum Diagonal Image Size: 100″
  • Minimum Projection Distance: 15.75″
  • Maximum Projection Distance: 66.93″


  • Lamp Type: LED
  • Number of Lamps: 1
  • Normal Mode Lamp Life: 20000 Hour
  • Economy Mode Lamp Life: 30000 Hour


  • Number of HDMI Ports: 1
  • HDMI: Yes
  • USB: Yes
  • VGA In: Yes
  • Audio Line In: Yes
  • Audio Line Out: Yes

Technical Information

  • Projection System: DLP
  • Projection Method: Ceiling, Front, Rear
  • Video Compatibility: EDTV, HDTV, SDTV
  • Computer Compatibility: Mac, Windows
  • 3D Capability: DLP 3D


  • Number of Speakers: 2
  • Speaker Output Power: 3 W
  • Speaker Output Mode: Stereo



The Acer K138ST isn’t much to write home about in terms of its looks. It’s not a beautiful device nor is it ugly…it just simply is. Around the front you’ll find the projector lens with a nice, well-secured lens cover. There are also slats for heat ventilation to help keep things as cool as possible and keep your projector going. Around both sides are more slats for heat ventilation giving this little guy plenty of room to breathe.

Around the back of the Acer K138ST you’ll find AUX in port along with a VGA port, HDMI port, AUX out port, DC 5V out and DC in. There is also a Kensington lock in case you happen to use this in an office or school where you may want to lock it down. Finally, on the back is the fan which pulls air in to keep the inner bits and pieces from melting into nothingness.

On the top of the Acer K138ST you’ll find the Acer logo and a control pad in case you happen to misplace the included remote. The control pad has a menu button, source button, resync button, power button and a D-pad type button that control forward/back, volume up/down and menu navigation. There is also a temperature light and lamp light on the top. Overall the design is pretty plain…nothing spectacular in terms of aesthetics, but it is well built and very light.



The Acer K138ST outputs at 720p with a max resolution of 1080p. That doesn’t mean you’ll be getting 1080p resolution here though. Max resolution simply means the highest resolution signal that the projector has been programmed to process and display. So the projector will take your 1920×1080 signal and scale it to the projectors native resolution of 1280×800. Inversely the same will happen if your source signal is less than the native resolution, the projector will scale the signal to fit its 1280×800 output.

That being said, 720p isn’t a horrible thing, of course 1080p and 4K are better but I found the Acer K138ST picture to be crisp and nice to view in a dark room. We used this projector on a wall for family movie nights and it displayed the content coming from my Macbook Pro very nicely. The display worked well in moderate lighting as well so it should work well for small conference rooms and meeting rooms. As with most projectors, it was harder to see under bright lighting but most people tend to at least dim lighting when using projectors anyway.

Watching a 1080p movie in 720p on a wall isn’t at all a bad experience. We found it was more about having fun just being able to do it than it was about how many pixels we were looking at. That being said, the Acer K138ST does have competition in the market and some of that competition does offer the higher 1080p for about the same price. Overall though, the display and picture that this little projector outputs is very nice.


Very poor performance when it comes to speakers here but you can’t really expect a whole lot from projector speakers anyway. The sound was tinny with very little low end while the mids were struggling to be heard. We used the projector with an external speaker using the AUX port and I would suggest you do the same if you purchase this device. The speakers are probably adequate for use in conference rooms when giving a presentation though. Presentations tend to be less dependent on dynamic sound and the room tends to be quieter.



Performance was great and the display is acceptable. The included remote is nice, basic and to the point, but works very well. The K138ST never got too hot but it did get warm just as most projectors will. Overall the performance was decent. Not stellar off-the-charts, but the K138ST gets the job done.


Acer has priced the K138ST at $899 retail but can be found on Amazon for $860 and possibly cheaper elsewhere. For $899 you’re getting decent performance and a decent picture with a basic design and build. There are other projectors on the market, we’ve not tested, that give better specs for around the same price so you’ll have some shopping around to do and a lot to consider.

Wrap Up

A decent home or office projector with the basics and not much more.

*One note. This projector is also known as the Acer MR.JLH11.00A
*We were sent a review unit of the Acer K138ST for the purposes of this review.

Last Updated on June 23, 2021.


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