MonitorsComputer Monitor
ASUS MB249 Monitor Manual
Setup, everyday use, maintenance and troubleshooting for the 23.8 in. Full HD monitor, with verified specifications.
- Screen23.8 in.
- ResolutionFull HD 1080p
- On-mode power13.4 W
- Est. yearly cost$7.26
About the ASUS MB249
This guide covers the ASUS MB249, a 23.8 in. Full HD monitor listed as ENERGY STAR certified. Its native resolution is 1920 × 1080 pixels (Full HD 1080p), about 93 pixels per inch.
It uses a TFT LCD panel with a rated maximum luminance of 250 cd/m² (nits). Listed signal and data interfaces include HDMI and USB. A USB-C port with Power Delivery can charge a connected laptop at up to 65 W while carrying video and data. Other listed equipment includes built-in speakers.
Measured on-mode power is 13.4 W, with 0.29 W in sleep and a total energy consumption (TEC) rating of 42.7 kWh per year — 12% below the ENERGY STAR limit for a display of this size and resolution. That TEC rating is lower than 58% of the 1,472 Computer Monitor models in our database.
Specifications
| Brand | ASUS |
|---|---|
| Model number | MB249 |
| Model name / series | MB249C |
| Display type | Computer Monitor |
| Screen size (diagonal) | 23.8 in. |
| Screen area | 242 sq. in. |
| Panel technology | TFT LCD |
| Native resolution | 1920 × 1080 |
| Resolution class | Full HD 1080p |
| Pixel density | 93 ppi |
| Maximum luminance | 250 cd/m² |
| Rated contrast ratio | 700:1 |
| Color spaces supported | sRGB |
| Enhanced Performance Display | No |
| Signal and data interfaces | HDMI, USB |
| USB-C with Power Delivery | Yes |
| Maximum USB-C charging power | 65 W |
| Built-in speakers | Yes |
| Power source | External AC adapter |
| On-mode power | 13.4 W |
| Sleep-mode power | 0.29 W |
| Off-mode power | 0.22 W |
| Total energy consumption (TEC) | 42.7 kWh/yr |
| ENERGY STAR TEC limit | 48.5 kWh/yr |
| Below ENERGY STAR limit | 12% |
| ENERGY STAR Most Efficient | No |
Safety information
- Place the monitor on a stable, level surface. When using a monitor arm or wall mount, choose one rated for the monitor's weight and VESA pattern and tighten it as instructed.
- Use only the external power adapter supplied with the display (or an identical replacement). An adapter with a different voltage or polarity can damage the monitor.
- Keep the ventilation openings clear and do not place the display near radiators, heaters or in direct sunlight.
- Do not expose the display to rain, moisture or spilled liquids. If liquid gets inside, unplug it immediately and have it checked before further use.
- Unplug the display during lightning storms or when it will be unused for an extended period.
- Keep fingers clear of the hinge and height-adjustment mechanism when tilting, pivoting or raising the screen.
Setup
Position the 23.8 in. screen about 20–30 in. (50–75 cm) from your eyes, directly in front of you, with the top line of text at or slightly below eye level. Tilt it back 10–20° and place it at a right angle to windows to minimize glare.
- Assemble the stand
Attach the stand or monitor arm while the display is lying face-down on the protective packaging or a soft cloth. Do not press on the screen.
- Connect the video cable
USB-C is the simplest option with a laptop: one cable carries video, USB data and up to 65 W charging power. If your laptop's own charger is rated higher than 65 W, it may charge slowly under heavy load — keep its adapter handy. HDMI works with most laptops, desktops and game consoles.
- Set resolution and scaling
In your operating system's display settings, select the native resolution of 1920 × 1080. At about 93 pixels per inch, a scaling setting around 100% usually gives comfortably sized text; adjust to taste.
- Adjust brightness
Set brightness so a white page looks similar to a sheet of paper under your room lighting — typically 100–150 cd/m² for office work, well below this model's 250 cd/m² maximum. Lower brightness reduces both eye strain and power use.
Using your monitor
Picture modes and color
Use the on-screen display (OSD) menu to choose a picture preset. The certification record lists sRGB color space support; use the matching mode (for example sRGB for web and office work) when color accuracy matters. Avoid "dynamic" contrast modes for photo editing, as they shift brightness with screen content.
Power management
The monitor enters sleep automatically when the computer stops sending a signal, dropping to 0.29 W. Set your computer to turn off the display after 5–15 minutes of inactivity so this happens during breaks. With the power button off, the monitor draws 0.22 W.
USB-C charging and docking
With a USB-C laptop connected, the monitor supplies up to 65 W through the same cable that carries the picture. Many monitors keep the USB-C port powered in sleep so the laptop continues to charge; check the OSD for a "USB charging in standby" option if you want to disable it.
Built-in speakers
Select the monitor as the audio output device in your computer's sound settings; audio is carried over HDMI or USB-C along with the picture.
Features
- USB-C Power Delivery
- Single-cable video, data and laptop charging (up to 65 W).
- Built-in speakers
- Plays audio from the connected computer or media player without external speakers.
Care and maintenance
| When | What to do |
|---|---|
| Weekly | Dust the screen with a dry microfiber cloth using light pressure. |
| When smudged | Power the display off, then wipe with a microfiber cloth lightly dampened with water. Never spray liquid directly on the screen or use ammonia- or alcohol-based glass cleaners on anti-glare coatings. |
| Every 3 months | Vacuum or brush dust from the ventilation slots and check that cables are fully seated and not pulling on the ports. |
| Every 6 months | Check the manufacturer's support site for firmware updates, especially if you see compatibility issues with new computers or docks. |
Troubleshooting
Most display problems trace back to cables, input selection or computer settings. Work through these checks before contacting support; for model-specific messages, consult the manufacturer's manual.
| Problem | Possible cause | What to try |
|---|---|---|
| "No signal" message | Wrong input selected; loose cable; computer asleep or outputting to another screen. | Select the correct input in the OSD, reseat both cable ends, wake the computer, and press Win+P (Windows) or check Displays settings (macOS). |
| Text looks blurry or the picture does not fill the screen | Computer not sending the native resolution; scaling or overscan settings. | Set the resolution to 1920 × 1080 and adjust OS scaling instead; turn off overscan or "aspect" options in the OSD. |
| Flicker, dropouts or black screen at high refresh rates | Cable not rated for the bandwidth; adapter or dock limitation. | Use a certified DisplayPort or Ultra/Premium High Speed HDMI cable, connect directly without adapters, or lower the refresh rate to test. |
| Colors look washed out over HDMI | Limited RGB range sent by the computer or console. | Set the output to full RGB range in the graphics driver, or match the monitor's HDMI range setting. |
| Monitor does not wake from sleep | Deep-sleep option on the input; graphics driver issue. | Press a monitor button or reselect the input; disable deep sleep / auto-input in the OSD; update the graphics driver. |
| Laptop not charging over USB-C | Laptop needs more power than the port supplies; cable not rated for charging; USB-C port on laptop is data-only. | Check that the laptop accepts USB-C charging and needs no more than 65 W; use the supplied or a 5 A certified cable; try another USB-C port on the laptop. |
| No sound from the speakers | Computer outputting audio elsewhere; monitor volume muted. | Select the monitor as the audio output device and raise the monitor's volume in the OSD. |
Energy use and running costs
The ASUS MB249 has a total energy consumption (TEC) rating of 42.7 kWh per year. ENERGY STAR's TEC method assumes the screen is on about 35% of the time (roughly 8.4 hours a day) and asleep the rest. At $0.17 per kWh, it costs about $7.26 per year.
| Daily use | Energy per year | Cost per year |
|---|---|---|
| 4 hours on, 20 asleep | 21.7 kWh | $3.69 |
| 8 hours on, 16 asleep | 40.8 kWh | $6.94 |
| 12 hours on, 12 asleep | 60 kWh | $10.19 |
On-mode power is measured at the factory-default brightness. Turning brightness up or charging a laptop through USB-C increases consumption; using short sleep timers reduces it.
Frequently asked questions
What size and resolution is the ASUS MB249?
It has a 23.8 in. screen with a native resolution of 1920 × 1080 (Full HD 1080p), giving a pixel density of about 93 ppi.
How much power does the ASUS MB249 use?
It draws 13.4 W when on and 0.29 W in sleep. Its ENERGY STAR TEC rating is about 42.7 kWh a year, or $7.26 at $0.17/kWh.
Can the ASUS MB249 charge a laptop over USB-C?
Yes. It has a USB-C port with Power Delivery rated at up to 65 W, so a compatible laptop can charge, send video and use the monitor's USB ports over one cable.
What inputs does the ASUS MB249 have?
The ENERGY STAR record lists HDMI and USB. Port counts and versions (for example HDMI 2.1 or DisplayPort 1.4) are not included in the certification data; check the manufacturer's specifications.
What panel type does the ASUS MB249 use?
It uses a TFT LCD panel with a rated maximum luminance of 250 cd/m².
Sources and disclaimer
Specifications on this page come from the ENERGY STAR certified monitors dataset published by the U.S. Environmental Protection Agency (record certified November 14, 2022), retrieved October 7, 2026.
The setup, operating, maintenance and troubleshooting guidance is written by ManualHarbor's editors for this specific product type and configuration. It is an independent guide — not a reproduction of the manufacturer's manual — and ManualHarbor is not affiliated with ASUS. Always follow the safety instructions, installation requirements and warranty terms supplied with your unit, and contact ASUS or an authorized service provider for warranty repairs and replacement parts.
Running-cost figures use assumed U.S. average utility prices and are estimates for comparison only. See our editorial methodology for details.
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