Issuu on Google+

Switching Bulbs bringing down costs Use this form to estimate how much carbon dioxide (CO2) and money you could save by switching all your bulbs to low energy equivalents. Follow steps 1 - 5. 1. Work out how many incandescent bulbs you have in your building of choice and multiply by 75 (as an average wattage). Enter this total wattage into box 1.


2. Divide your total wattage by 1000 to change your watts (W) into kilowatts (kW). Write this new figure in box 2.


3. Electricity is measured in kilowatt hours. To find out the kilowatt hours of electricity your bulbs use in a year, multiply your kW by 996.



3 ________




(the average bulb in the UK is on for 2.73 hours a day. 2.75 x 365 days in a year = 996.)

Now follow the last two steps below to find out what your old bulbs’ costs and CO2 emissions are now and what they could be if you switched all these bulbs to low energy equivalents.

4. Multiply your kWh by 0.15 and enter into box 4. Multiply your kWh by 0.43 and enter into box 5. 5. To find out the cost and CO2 if all these bulbs were low energy: Divide your figures for both cost and CO2 by 5. Enter the new amounts into boxes 6 and 7.


Cost 5


£ ___________ 6

per year


£ ___________


high energy

kgCO2 per year

÷5 7

per year

low energy


kgCO2 per year

WORKSHEET lighting savings.pdf