required. If an accurate reading per day, month or year is required then it is highly recommended to keep the appliance plugged
into the Energy Control and to operate it normally for at least a few days. This is so that it can take an average of the power
used and its cost over the time period.
The longer the Total Cost of an appliance is monitored by the Energy Control, the more accurate any forecast (day, month, year)
or Total Cost reading will be. There are a variety of reasons for this, some of them are:
•
The power supply to the mains from the Electricity Company is never constant and at some stage will vary slightly. For
example, if electricity varies by 1% for every 1 second of usage and the Energy Control is used for only 5 minutes then
the cost forecast will not be as accurate compared to use for 3 hours with the same variation of 1% for every 1 second
in the power supply.
•
Some electrical appliances use more electricity when first turned on than others and the amount of electricity it uses
will decrease the longer it left operating (commonly referred to as "Warming up").
Example 1:
A lamp is plugged into the Energy Control and operated every evening:
Day 1, from 18.00hrs to 20.00hrs
Day 2, from 19.00hrs to 21.00hrs
Day 3, from 18.30hrs to 20.30hrs
Assume it costs 1.00 (€, £ and etc.), per hour to run this lamp, the Total Cost at 20.00hrs on day 1 would be 2.00(€, £ and
etc.). If Total Cost per day is required then it will show 24.00 (€, £ and etc.) - at this point the Energy Control is assuming the
lamp will be left on all day for 24 hours, but this is not the case. At 18.59hrs on day 2, the Energy Control will show the Total
Cost as the same at 24.00 (€, £ and etc.) but now the cost per day would have dropped to about 2.00 (€, £ and etc.) as it has
not been used for the last 23 hours. Before the lamp is turned "ON" on day 3, the Energy Control will have taken the total power
consumption and the length of time that it has been turned off and averaged them out for an accurate cost per day reading.
This should show 2.00 (€, £ and etc.) and so you know how much, on average, the lamp is costing to operate everyday.
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