Liquid Crystal Display (LCD) Monitors
It makes business sense to choose the most energy-efficient computer equipment possible. Energy-efficient computer equipment uses less energy than conventional computer equipment saving energy and money, as well as aiding in reducing greenhouse gas emissions. When it comes to computer monitors, liquid crystal display (LCD) monitors are the energy-efficient choice. Their energy efficiency, combined with their other advantages, makes them a better long-term investment. When it's time to replace your computers, consider switching to LCD monitors.
LCD versus CRT Computer Monitors
There are two types of computer monitors: CRT (cathode-ray tube) and LCD. CRT monitors are the traditional monitors we have used for years and are typically heavy and bulky in size. A CRT monitor uses cathode-ray technology found in televisions. A cathode shoots electron beams through a vacuum tube, exciting phosphors, which create a glow at the front of the screen. As a continuous source of energy is needed to activate the phosphors, the electricity consumption of a CRT monitor remains steady.
A typical LCD monitor is thin, compact, lightweight, and sometimes referred to as a flat-panel display screen. LCD monitors use similar technology to that of digital watches. In LCD monitors, transistors charge liquid crystals between two glass plates. Fluorescent tubes provide the light source, which passes through a layer of crystals. Varying the electrical charge to the crystals creates images. An LCD monitor uses less electricity than a CRT monitor because it needs no energy, other than the fluorescent light source, to produce the white background that makes up most screen images.
Benefits
- Energy savings – At 25 watts, an LCD monitor uses about one-third the energy of a 75-watt CRT monitor.
- Longer lifespan – LCD monitors last twice as long as CRT monitors, reducing the need for periodic replacement. Replacing your LCD screen's backlight is an economic way to prolong the life of the display.
- Reduced heat output – Decreased cooling loads result in decreased cooling costs.
- Space-saving benefits – With their slimmer profile and lighter weight, LCD monitors take up to 75 percent less desk space than CRT monitors. They work well with laptops and can also be wall-mounted.
- Health benefits – LCD monitors are flicker-free, anti-static, anti-glare and produce no electromagnetic radiation.
- Better total cost of ownership – Although LCD monitors are more expensive than CRT monitors, prices have decreased, making them more affordable. Considering the advantages of longer lifespan and greater energy efficiency, LCD monitors provide a better long-term investment.
Recent advances in LCD technology have improved the contrast, brightness and colour display of LCD monitors, making them comparable with CRT monitors.
The Energy Cost Advantage
The table below outlines the energy cost savings of an LCD monitor over a CRT monitor in typical facilities.
| Office Building | School | Hospital | |
| Hours of use per year per computer | 3,900 1 | 2,500 2 | 8,760 3 |
| LCD energy usage (@ 25 W) | 97.5 kWh | 62.5 kWh | 219 kWh |
| CRT energy usage (@ 75 W) | 292.5 kWh | 187.5 kWh | 657 kWh |
| Savings offered by LCD monitors (demand reduction 50 W) | 195 kWh | 125 kWh | 438 kWh |
| Annual electricity cost savings per LCD monitor * | $9.75 | $6.25 | $21.90 |
| Annual electricity cost savings per 1000 LCD monitor * | $9,750 | $6,250 | $21,900 |
* Based on an electrical rate of $0.05 per kilowatt hour
1 Assume hours of occupancy of 14.8 hours a day, five days a week
2 Assume hours of occupancy of 9.6 hours a day, five days a week
3 Assume hours of occupancy of 24 hours a day, seven days a week
Using the office building example, the total savings add up to 195 kWh per year for each LCD monitor. This translates into an estimated $9.75 in annual savings for a single computer. For an office building with 1,000 computers, LCD monitors would provide approximately $9,750 in annual energy savings.
These savings are just the beginning as some monitors are left on at night and on weekends. Using the office building example again: if 30 per cent of monitors are on after hours, with an average 4,860 hours of running time per year, a single LCD monitor would save an estimated additional 73 kWh per year or approximately $3.65 in annual electricity costs.
The total savings offered by LCD monitors are significant. When factoring day and after hours of run time, the annual savings translate into an estimated $13.40 per LCD monitor. For an office building with 1,000 computers, LCD monitors would provide approximately $13,400 in annual energy savings.
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