Energy Saving Calculation
How we calculate your annual energy savings over a 1 year period (any savings shown do not include VAT)
We use the following facts and assumptions:
Cost for 1kW of Electricity = £0.215
BERR Department of Business Enterprise and Regulatory Reform 2006 figures)
1kW = 1000watts
(e.g. 60W = 0.06kW)
Average yearly run time = 2500 hours
(estimate based on an average use of 6.8 hours per day)Step 1:
Calculate the total cost to run a light bulb
= [wattage(kW) x average yearly run time(hrs) x cost for 1kW (£)]
Example 60watt light bulb
Cost (£) = (0.06 x 2500 x 0.215)
Cost (£) = 32.25
Step 2:
Calculate the total cost of light bulb replacements
= (number of light bulbs used x cost of light bulb
Number of light bulbs used
= [average yearly run time(hrs) / lifetime of bulb(hrs)]
Example 1000hr £0.30 light bulb
Cost of Light bulbs used = [(2500/1000) x 0.30]
Cost of Light bulbs used = £0.75
Step 3
Calculate the total cost of ownership of the light bulb for 1 year
= Total cost to run (Step 1) + Total cost to replace (Step 2)
Total cost as per example
£32.25 + £0.75 = £24.19