Home Office Equipment

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As you go about setting up your home office with a new computer, printer, fax machine, and maybe even a copy machine, consider that this equipment is going to add to your electricity bills. A computer alone may not use more energy than your television, but once you've put it all together, an office full of equipment can definitely make its mark on your energy use.

Many electronic devices continue to use electricity even when switched off. Most draw only a few watts, but with several pieces of office equipment, the power drain can add up. The only solutions are to physically unplug these appliances, or to turn off their power strips. This is easy, and it protects your equipment against voltage surges such as lightning strikes.

You'll obviously have other considerations besides energy when you buy your equipment, such as speed and capacity. Fortunately, you can find ENERGY STAR labels on almost every type of office equipment, at all levels of speed and features. ENERGY STAR devices will have lower operating costs than other equipment.


Newer computers tend to be more energy-efficient than older ones. This is partly because the demand for portable or laptop computers drove manufacturers to make more efficient components so batteries would last longer. These efficiency improvements now appear in desktop machines. That doesn't mean that they will actually use less energy than older computers however. Why? Because the new computers can do more—and that requires more power.

It's hard to compare the energy use of different computers. The rated power levels found on the nameplate only give the maximum capacity of the power supply. They don't accurately reflect the average power usage, which tends to be much lower. However, we can make a few generalizations.

Laptop computers use much less energy than desktop computers. A typical laptop uses a maximum of 15 watts and it powers down (goes to sleep) when it's not used for several minutes. A typical desktop computer uses about 130 watts (including the monitor). If you are buying only one computer, a laptop offers the extra versatility of being portable. On many laptops, you can hook up a separate full-size monitor and keyboard for use when you're at home.

For desktop computers, an ENERGY STAR label tells you that the computer has a sleep feature. Although not quite as good as turning the machine off, this is very useful if you must leave your computer on all the time to receive faxes through a fax-modem. Just check to make sure that the sleep feature will wake up the computer for incoming phone calls.

Computer Monitors

The monitor accounts for about half the energy use of a typical computer setup. Large monitors use more energy than small ones—a 17-inch color monitor uses about 35% more energy than a 14-inch color monitor. Color monitors use up to twice as much energy as monochrome ones. And high-resolution monitors use more energy than low-resolution models. Most monitors use cathode ray tube (CRT) technology. But many laptop computers have liquid crystal displays (LCDs). Color LCD monitors use only 10% to 20% as much power per square inch as color CRT monitors.

Like computers, ENERGY STAR monitors have a sleep feature that powers them down (to 30 watts or less) after a period of inactivity. You can also cut your monitor's energy use by turning it off whenever you aren't actively using it. Even if you hesitate to turn off your computer for half an hour because you don't want to wait for it to start up again, you can still turn off the monitor.


Printer energy use varies widely. Generally, the faster and higher-quality the printer, the more energy it uses. But the biggest differences are among the different types of printer. Dot matrix printers use relatively little energy, but many people dislike their inferior print quality. Laser printers are energy hogs, both during active use and in standby mode.

If you don't absolutely need the speed and superior quality of laser printouts, consider getting a high-end ink jet printer, which will also cost a lot less up front. Ink jet printers cannot compete with lasers when it comes to speed, but the print quality is quite good on newer models—easily good enough for most home office uses. Ink jet printers print well on used paper, so you can print drafts on the back side of old work. This feature also allows you to make double-sided printouts. (Laser printers tend to jam if you feed used paper into them.) Reusing paper saves the energy used to make new paper (an average of 15 watt-hours of energy is used to produce a single sheet of paper), and it saves you the money of purchasing it.

If you do decide on a laser printer, you can cut energy use substantially by getting a somewhat slower one. And turn the printer off when it's not in use. Most printer energy is used while the machine is on standby. ENERGY STAR printers, like computers and monitors, go into a low-power (sleep) mode when they haven't been called upon to print for awhile. If you're getting a high-end laser printer, look for one that will print double-sided.


A copier could be the highest energy user in your home office, especially if you leave it on all day. Unless you're running a copy center, you probably don't need a high-volume copier that can spew out 60 copies per minute. But even a low-volume copier uses 40 to 70 watts during standby and 1,400 to 1,600 watts when copying. These numbers do not always appear on the equipment; instead, they are often labeled only for peak power. Ask the dealer what the American Society for Testing of Materials (ASTM) energy rating is for a copier you might buy. Look for the most efficient model in the speed category you want.

All ENERGY STAR copiers have an "energy saver" (sleep) setting and duplexing capability (that is, they can copy double-sided). Look for a machine that has a short "time to first copy" when you bring it back from sleep. Also, turn the copier off whenever you don't need it to be ready to copy at a moment's notice.


Fax machines can use a lot of energy because they are generally left on constantly to receive incoming calls. Their standby energy use may therefore be more important than their active energy use. ENERGY STAR fax machines must have a low-power sleep mode and the ability to scan both sides of a sheet of paper. To further reduce power use, you should consider turning off the power when a fax won't be used for a while.

There are currently four main types of fax machine on the market: direct thermal (which uses heat-sensitive coated paper); thermal transfer (which can use plain paper); ink jet; and laser.

Laser faxes have the highest print resolution and use the most energy. They are also quite expensive. Ink jet faxes use the least energy, and print with relatively high resolution on plain paper. Machines that use thermal paper are the least expensive to buy, but the paper is about three times as expensive as plain paper, has a short shelf life, and is difficult to write on. If you get a lot of faxes, an ink jet may pay for itself in saved paper costs within a year or two.

Most fax machines can also be used to make copies. If you usually need to make only a few copies from paper that can be fed through the machine (as opposed to pages from a book), you won't need to buy a separate copier.

Combination Equipment

Space is often a consideration in a home office, and you may not have room for a separate copier, fax machine, printer, and scanner. Combination machines can save energy because you eliminate the standby losses of having four machines. ENERGY STAR labels now appear on the most energy-efficient combination equipment.

Myths About Home Office Equipment

Myth 1: It's better to leave computers on constantly than to turn them off when you're not using them.

This was true back in the days of the mainframe, but it's not true anymore. The lifetime of your hard disk is typically limited by head-disk mechanical interactions and wear, rather than by electrical surges and thermal cycling during start-up. It's a good practice to turn off your computer and monitor (as well as your printer and copier) if you don't plan to use them again within the next half hour.

Of course, many people now use a fax-modem on home computers and may need to leave the central processing unit (CPU) on to receive faxes. If this is the case, at least turn off the monitor when it's not in use. Monitors, especially full-color units, can use as much energy as the CPU. Some CPUs can also be put to sleep when awaiting faxes, rather than left on at full power.

Myth 2: Screen savers save energy.

Most screen savers do not save energy, unless they actually turn off the screen or, in the case of laptops, turn off the backlight. Flying toasters or fireworks use about as much energy as word processing. If you want to save energy and save the screen, turn the monitor off by its switch (or its power strip) when you're not using it.

Myth 3: Laser printers don't use much energy when they're not printing.

Laser printers draw about one third of their printing power when they are on standby. For a laser printer capable of putting out eight pages per minute, this means 100 watts. Turn off your laser printer when you're not printing.

Myth 4: An ENERGY STAR computer will automatically power down ("put itself to sleep") when it isn't used for a certain period of time.

ENERGY STAR computers come with sleep capability—but the sleep feature has to be turned on before the computer will automatically power down when not in use. Many computers come with this feature turned off, and it's not always obvious how to activate it. Make sure your new ENERGY STAR computer comes with the sleep feature turned on, or clear instructions on how to turn it on. Finally, use the sleep feature only as a backup. You should still turn the computer off when you're not using it.


American Council for an Energy-Efficient Economy. "Guide to Energy-Efficient Office Equipment", Revision 1. Palo Alto, CA: Electric Power Research Institute, Inc., 1996.

Leslie, Russell P., and Kathryn M. Conway. "The Lighting Pattern Book for Homes". Troy, NY: Rensselaer Polytechnic Institute, 1993.

Excerpted with permission from No-Regrets Remodeling by Home Energy (1997)