ENERGY STAR® Qualified Office Equipment

Personal Computers and Monitors

In a typical office, computer/monitor combinations far outweigh all other office equipment in terms of energy consumption. The good news is that this offers significant opportunities to achieve energy savings by purchasing ENERGY STAR qualified machines and encouraging users to turn them off when not in use.

ENERGY STAR Criteria

To qualify for the ENERGY STAR symbol:

• Computers must have the capacity to automatically switch into a low-power "sleep" mode, where the unit consumes no more than 4 watts of power after a preset period of inactivity.
• Monitors must have two low-power sleep modes, first reducing energy use to no more than 2 watts and then switching to a "deep sleep" mode (also known as off mode / stand by power) of 1 watt or less. In ‘’On’’ mode, the maximum allowed power varies based on the computer monitor’s resolution.

View our list of ENERGY STAR qualified models

Please note: We are currently sharing lists of ENERGY STAR qualified office equipment with ENERGY STAR in the United States. When you click on the products above, you will be taken to a product list on the U.S. ENERGY STAR web site. Many of the products listed are available in Canada. To return to Canada's ENERGY STAR web site, simply click on the "Back" button on your web browser.

• List of models: Personal computers
• List of models: Monitors

Features of an Energy-efficient Computer - Energy Efficiency Gains for Desktop Units

Significant improvements have been made in the energy efficiency of desktop personal computers (PCs) over the past decade, thanks in large part to the migration of energy-efficient features from the world of laptops to desktop machines.

The most important of these features is the power management capability that places the computer and monitor in sleep mode when they are not being used. While in this mode, computers consume up to 90 percent less electricity than when fully operational, although they are available essentially on demand (i.e. the system does not have to be rebooted). A simple touch of any key on the keyboard or movement of the mouse is enough to bring computers out of their sleep mode. This power management capability is mandatory for a computer to meet the ENERGY STAR technical specifications.

Monitor Options

The type of display technology you choose for a computer system has an important impact on energy consumption. For desktop computers, the most common displays are cathode ray tubes (CRTs), which typically consume about half as much electricity as the computer itself. CRTs consume significantly more energy than liquid crystal display (LCD) monitors. As well, colour monitors consume more electricity than monochrome units. CRT electricity requirements also increase in conjunction with display size and resolution.

Flat screen display technologies, which originated in laptop computers but are becoming popular in desktop applications, consume only about one-third the energy of a CRT. Flat screen monitors offer excellent resolution (particularly LCD models) and are much thinner than conventional monitors, which means they occupy less space on your desk. However, they can be more expensive to purchase than CRT monitors of comparable size.

Whichever technology you select, make sure it has a power management feature that will automatically switch the monitor into sleep mode (and preferably a deep sleep mode) after a preset period of inactivity (remember, this is mandatory to bear the ENERGY STAR symbol).

Laptops Are Energy-Efficiency Winners

The most energy-efficient computer/monitor combination is a laptop unit. Laptops use a maximum of 15 watts (compared with 80 to 160 watts for desktop PCs) and automatically power down (go into sleep mode) after several minutes of inactivity (figures from a 2002 study).

However, their lower energy consumption does not necessarily mean that laptops will save you money in the long term. Laptops are usually more expensive to purchase than comparable desktop units. The cost and inconvenience of recharging and eventually replacing batteries must be considered. In addition, laptops generally have inferior displays and do not offer the full range of features available in desktop units.

Still, laptops can be ideal for certain applications, inside and outside the office. When purchasing a laptop, compare the integrated or advanced power management features of different models. Although they are likely quite similar, some models may have additional energy-saving features.

Making the Right Choice

When purchasing a new computer and monitor, it is important to match your needs. Although the addition of unnecessary hardware will likely increase a PC's energy requirements, you will want to ensure that the machine gives you the functionality needed for the tasks you want to perform (whether at work or at home). Keep the following points in mind:

Keep the following points in mind:

• As a rule, the faster the processor speed, the more energy the machine will use.
• The larger the memory (RAM), the greater the energy consumption.
• The addition of extra "boards" or components (e.g. CD writers) will likely increase the system's energy requirements.
• Nameplate power ratings can provide a useful but imprecise comparison of energy use (due to the lack of common measurement standards).
• From an energy efficiency perspective, in order of efficiency are the
  • LCD monochrome backlit monitor
    consumes 2 to 5 percent of the electricity of a colour CRT)
  • LCD flat screen monitor
    (consumes 10 to 20 percent of the electricity of a colour CRT)
  • monochrome CRT monitor
    (consumes 50 to 65 percent of the electricity of a colour CRT)
• Screen savers do not save energy: they protect screen phosphors (in fact, some screen savers are so complex they increase energy consumption).
• Consider purchasing upgradeable machines so you can install bigger hard drives or new microprocessors as your needs change, rather than purchasing an entirely new computer.