Display Power Consumption: CRTs Versus TFT-LCDs

Conclusion

We can confirm that the TFT display with LED backlighting is indeed lowest on overall power consumption. Of course, we're only talking about the displays in our lab here, not generalizing about the entire display market. With that said, other LED-lit displays are likely lower on power consumption than models with fluorescent lighting. The overall image is colder and may appear bluish, but this can be adjusted in the monitor settings.

We can also confirm that CRTs will require at least twice the power of an LCD display. You could operate three large, modern LCDs with the power consumed by one 19” CRT, and this ratio will probably become 4:1 very soon. If you care about energy savings, you should dispose of your old CRT monitor once you find a good deal on a decent LCD. Even if power isn’t your primary concern, consider that LCDs don’t get as hot as CRT monitors for the very same reasons. We found that it’s hardly possible to reduce power consumption by decreasing monitor brightness, but LCD power draw varied significantly as brightness changed. Specifically:

• We could reduce power consumption by up to 65% just by reducing brightness.
• Newer displays will show more significant power savings with reduced brightness.
• Larger displays need more background light, but operating power can still be reduced.
• Even older displays require less power if brightness is reduced.

A 20% brightness reduction might not impact your visual experience very much, but it could reduce the power consumption of your display to a larger extent than typical efforts to reduce system power consumption by using low-power hardware, such as an efficient power supply, green drives, or SSDs.

We recommend checking your display brightness setting. Working with documents and spreadsheets typically doesn't require more than 250 cd/m², and many people habitually set their monitors with too much brightness. You couldn't ask for easier (free) power savings. Those looking for a new display should target high contrast ratios, since this allows for decreasing the brightness. Of course, be sure to account for personal preferences, environmental lighting, hardware, and your applications when choosing brightness settings. Power savings shouldn't have to result in eye strain.