Energy myths and realities

Below is a list of myths about energy savings.

Myth: Energy efficiency and energy conservation are the same thing.

Reality: Well-intentioned information campaigns during oil crises of the 1970s created a lot of confusion about how to save energy and even about how to talk about saving energy. Energy efficiency means getting a job done with less energy. Energy conservation, on the other hand, means reducing the level of services such as reducing lighting or turning up the thermostat of your air conditioner.

Myth: Buying an efficient air conditioner or furnace will automatically reduce my energy bill.

Reality: This is true to some extent, but you won't realize all the possible savings if the equipment is not sized or installed properly. Studies have shown that typical air conditioners and duct systems are improperly installed, wasting one-third or more of the energy used by the air conditioner. New and replacement equipment (and ducts) need to be properly designed and installed to realize all the possible savings. The same caveats about proper installation hold true for insulation, windows and many other energy-efficiency upgrades.

Myth: Turning up (or down) the thermostat will make your home get warm (or cool) faster.

Reality: It's tempting to think of a thermostat like a water tap — the wider you open it, the more water (heat/cold) will come out. In reality it works more like a light switch in that if it's "on," the same amount of light (heat/cold) will come out.

Myth: Duct tape is good for sealing ducts.

Reality: Unfortunately, laboratory research has concluded that duct tape has very low durability when used to seal ducts. On new installations, tape may fall off because of poor surface preparation, as ducts are installed in dirty and dusty locations and conditions. On older systems, the tape falls off as it ages, and the adhesive dries out and tends to wrinkle.

Myth: When my appliance is turned off, it's off.

Reality: We've found that most devices continue to consume power when they're switched off — sometimes as much power as when they're on! They are called energy vampires.

Myth: Leaving lights, computers and other appliances on uses less energy and makes them last longer than turning them off.

Reality: The small surge of power created when some devices are turned on is vastly smaller than the energy used by running the device when it's not needed. While it used to be the case that cycling appliances and lighting on and off drastically reduced their useful lifetimes, these problems have been largely overcome through better design.

Myth: Halogen lighting is super-efficient.

Reality: It's true that halogen lights use slightly less energy than standard incandescent bulbs, but halogens require transformers that can use extra energy, even when the light is off. They are also a fire hazard. By comparison, compact fluorescent lights (CFLs) are nearly three times as efficient and don't pose a fire hazard. Many new models are dimmable, like halogens.

Myth: Leaving a fluorescent light turned on is cheaper than turning it off and on.

Reality: You should turn off your fluorescent lamps if the space is not going to be occupied for more than a few minutes (three to five minutes is a good rule of thumb). The modern electronic ballast and T8/T5 lamp combination do draw a higher level of current during startup, but it only lasts for a fraction of a second, which is negligible compared with normal current requirements of the lamps.

A bigger concern here may be the impact of frequent on/off cycles on a lamp's life. This does shorten a lamp's life somewhat; however, leaving the lights on all the time also reduces a lamp's life. It has been shown that even though occupancy sensors reduce a lamp's life as measured in total hours, they actually extend the calendar life of a lamp because the lamp operates only during those hours that are needed.

Myth: It uses less energy to boil water if you start with hot water from the tap.

Reality: The same amount of energy (and essentially the same amount of money) is used whether you use hot or cold water. If you use hot water, you've already paid to heat the water in the water heater. Get more cooking tips.

Myth: A power factor correction device can reduce my residential bill.

Reality: The U.S. Environmental Protection Agency states that it has not seen data that prove these types of products for residential use accomplish what they claim. Get more details.