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Can We Save The World ?
Monitoring residential electricity use
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Electricity is our most versatile energy source, we use it in innumerable ways, because of this it
can be difficult to
know where electrical energy is used.
Two devices that be useful for monitoring residential electricity use and cost are the Kill a Watt,
and the Centameter, or Cent-a-Meter.
Kill a Watt
The Kill a Watt electricity use monitor is inserted between a wall outlet and a power cord, it
shows a number of electrical characteristics, the power used, and the cost.
The Kill a watt enables you to figure the cost of using plug in electrical appliances, it
accumulates and can display the electrical energy used over a period of up to 9,999hrs.
Kill a Watt meter, click for a larger image
The Kill a watt only measures the power used from a wall outlet. In contrast the Centameter
electricity use monitor continually and remotely monitors and displays the total electrical power
currently being used in your home.
The Cent-a-meter enables you to monitor total present home electricity use and helps you
identify all the items and appliances that consume electrical power, how much they are consuming,
and to figure the costs.
Cent a Meter, click for a larger image
The Centameter generally uses electrical current monitors that fit around the two main electric
cables that come into your home, the monitors are connected to a nearby wireless transmitter.
The portable receiver and display unit can be operated up to 100 feet from the transmitter.
After installing a Centameter unit I suggest you operate each of the breakers on your indoor
load center, breaker box, or fuse box in turn, this will give you an indication of the area
where the electrical power is being used.
From there you can carry the Centameter with you as you turn electrical appliances and
lights, in the area identified, on and off in turn noting the electrical power usage.
Even after you have identified the devices consuming electrical power and you have turned most
everything off you will find that the power consumed varies somewhat. This is usually because
some of the devices in your home, e.g. your refrigerator, freezer, heating and cooling systems
are thermostatically controlled, and switch between standby and operating modes.
You will probably also find that your home continually consumes a small amount of electricity,
this powers equipment like bell transformers, intruder alarm systems, smoke alarms, cordless
telephones, electrically powered clocks, garage door openers, and other equipment that is left
Typically homes continually consume 100 to 300watts. If your home continually consumes 100 watts
over a year this equates to an energy use of 874 kilowatt hours. Assuming the average cost of a
kilowatt hour is 10c, the annual cost is $87.
It has been estimated that if standby power could be reduced to a negligible amount, 26 US power
stations could be closed down.
Fortunately the awareness of electrical equipment designers and manufactures of this is growing,
in part because of the Energy Star Rating system for appliances, progress is being made to reduce
electrical appliance standby power consumption.
Fit switched power strips to TV Video and Audio appliances, PC equipment and other equipment
that need not be left in standby mode then use either the Kill a watt or the Centameter to
calculate the savings you can make by switching unessential equipment off.
The Cent-a-meter display should be placed where it can be easily and often seen and so prompt
you to switch off non essential items. Look at it often and especially before going to bed or
if you are leaving your home for a while, to check how much electricity is being consumed.
The Centameter and Kill a Watt units allow you to reduce home electricity use by 25%, it can
quickly show you if something has inadvertently been left switched on.
Be energy frugal; if itís not essential switch it off. Educate those in your home about
the large energy and cost savings that can be made by monitoring residential electricity use.