The average Canadian and US home is said to leak at least 50 Watts of electricity continually, about 450 kilowatt hours per year. “Leaking electricity” and “invisible loads” cost us all, and costs the environment.  

The water heater information is calculated not measured.

What is Phantom Power?

The highest phantom load discovered were the compressor heaters on some air conditioners and heat pumps. Because these are rare and the statistical sample was 2 we did not include them within the chart above. Other heavy phantom loads discovered were  within standby generators with sump heaters and  battery blankets and built in battery chargers. 

Power supplies that come with electronics are either built-in or external (small square black plug), they’re needed to convert AC electricity from a standard wall socket into DC or lower voltage AC electricity. The problem is that they’re notoriously inefficient at energy conversion.  

A typical power supply today loses about 30 per cent of the energy it draws from the wall, much of it in the form of heat loss. The test is simple: the more your power supply heats up, the less efficient it is at energy conversion. Go ahead, feel the temperature of that cell phone or cordless phone battery charger transformer when it’s not in use.  It will be warm.  Unplug these and any other appliances on our list when they are not in use and save real money!

How do I calculate  monthly energy cost?  

This is a simple calculation but requires an understanding of the difference between energy (Watt hours) and power (Watt).  Electrical power is the flow of electricity like gallons per minute of water, but the monthly electrical bill is an amount of electricity like total gallons in our example and it is expressed as kilowatt-hours (units of 1000 Watt hours) . To convert the flow to an amount of energy to kilowatt hours, multiply by the duration or time, in our example, one month

Energy = Power X Time   (Watt hours = Watts X Hours)

A measure of electrical energy is kilowatts.  Utility billing rates are expressed in kilowatts hours (cost per kW.hr)  When using kilowatts, the time unit is hours and Watts are divided by 1000.  

To Calculate the amount of  kilowatts used in a month

Formula

Hours in a month = 720 hours  (30 days x 24 hours)

A 100 W appliance’s consumption can be expressed as 0.1 kW (100 W ÷ 1000) 

If this appliance is operated constantly for a month, then the energy consumed would be: 72 kW.hr per month 
(0.1 kW X 720 hr per month)

Calculating Cost:

If electricity costs 10 cents/kW.hr, then that appliance’s cost  is $7.20 per month to operate  (72hr x $0.10).  

A common error in the calculation is not converting the power from Watts to kilowatts, resulting in an answer that is a thousand times too high. 

(Note:  W = watts, kW = kilowatts, and kW.hr = kilowatt hours.)

Source: www.enviroharvest.ca/phantom_loads.htm (Oct 2, 2015)