Lighting/Cups of Tea

Assumption
Switch a light off before you go home and save enough energy to make 32 cups of tea

Calculation
Assuming a 4ft fluorescent tube uses 0.036kWh, and is left on when the building is unoccupied for 16 hours (5.30pm-8.30am).

0.036kW x 16 hours = 0.576kWh.

There are 8 cups of water in a standard kettle. Assuming the kettle will be boiled with cold water each time, at least 0.576kWh is used to boil 4 full kettles

Therefore, Switch a light off before you go home and save enough energy to make 32 cups of tea.

Lighting/Dishwasher

Assumption
Switch 2 lights off before you go home and you’ll save enough energy to run a full dishwasher

Calculation
Assuming two 4ft fluorescent tube use 0.072kW, and are left on when the building is unoccupied for 16 hours (5.30pm-8.30am).

0.072kW x 16 hours = 1.152kWh.

At least 1.152kWh is used to run 1 full dishwasher

Therefore, Switch 2 lights off before you go home and you’ll save enough energy to run a full dishwasher

PC/Microwave

Assumption
Turn your PC off before you go home and you’ll save enough energy to microwave your next dinner

Calculation
Assuming a standard PC monitor is left on stand by uses .005kWh, and is left on when the building is unoccupied for 16 hours (5.30pm-8.30am).

0.005kW x 16 hours = .08kWh.

At least .08kWh is used to microwave 1 meal

Therefore, Turn your PC off before you go home and you’ll save enough energy to microwave your next dinner

PC/Washing Machine

Assumption
Switching your PC monitor off after work for 1 week will save enough energy for a full washing machine load

Calculation
Assuming a standard PC monitor is left on stand by uses .005kWh, and is left on when the building is unoccupied for 16 hours (5.30pm-8.30am) for 7 days.

0.005kW x 16 hours x 7 days = .56kWh

At least .56kWh is used to run 1 full washing machine (1 hour cycle)

Therefore, switching your PC monitor off after work for 1 week will save enough energy for a full washing machine load

PC/Energy Bill

Assumption
Turning your computer off at night will save on average 25% of its annual energy bill

Calculation
A Computer uses 85 Watts for 24 hours = 2040 W
A Computer saving 85 Watts for 8 hours = 680 W
Difference (saving) = 33% saving. (33% of the time)

Assuming the PC would have been using minimal power overnight when on but not in use, 25% is a more realistic figure.

PCs and monitors will still use a little energy (5W) unless switched off at the mains. This calculation is based on leaving the PC running (booted up) all the time.

For an office, the out of office hours are likely to be longer….weekends, savings could be more like 50%