Exploring how we use electricity in the home. A simple way to think about watts, kilowatt hours and energy bills. A presentation I produced for Global Action Plan's Big Energy Race.

1. How much electricity is that?
Ways to understand your
home electricity use
© Global Action Plan. Charity registered in England and Wales number 1026148, and in Scotland number SC041260

2. Quiz: Which uses electricity most quickly?
Can you put these in order?
Watch to the end to see if you were right!

3. Imagine if all of your electricity
was generated by a bloke on a bike…
They can produce about 100 watts of electricity.
Meet Paul … and his energy bike.

4. But what is a watt?
Watts show how quickly things
use electricity
The higher the watts, the
faster the red light flashes (or
the wheel spins round) on
your electricity meter.
60w
Electrical items are labelled by
how many watts they use.

5. You switch on a low energy
light bulb…
8 watts…
No problem for Paul and his trusty steed.

6. Then you try an old-fashioned
40 watt bulb as well…
48 watts…
A bit trickier, but Paul’s still coping.

7. You put your laptop on to send
some emails…
Up to 100 watts in total…
That’s about as much as Paul can manage

8. All that work makes you thirsty,
so you put the kettle on…
Now Paul needs 29 friends to
help, all called Paul.

9. But, kilowatt hours are more important -
So, watts tell you how quickly
0 watts 1,000 watts 2,000 watts 3,000 watts
Low energy lightbulb
6-23 watts
Vacuum Cleaner
800-1,000 watts
Kettle
2,000-3,000 watts
something uses electricity
they’re what you pay for…

10. Kilowatt hours tell you how much
electricity you have used
This is shown on your
electricity meter…
… and your bills or
annual statement
ElecCo
Mr I. Am
My House
My Street
My Town
Your annual
electricity statement
Last year you used …
3399.98 kWh (kilowatt hours)

11. Paul can produce about 100 watts
In 10 hours he’d produce …
100 watts x 10 hours = 1,000 watt hours or 1 kilowatt hour
(That’s one unit of electricity.)
of electricity …

12. A 40 watt bulb uses
1 kilowatt hour
if it’s switched on for 24 hours
A fridge freezer (80 watts) could use
the same in 12 hours.
An electric shower would take just
6-7 minutes – they’re 7.5-10 kW.

13. Your energy bill tells you how much
you pay for a kWh (unit) of electricity
ElecCo
Price per kWh: 14p
Your electricity bill
Once you know this you can
work out how much your
appliances cost you to run…

14. E.g. a 60 watt lightbulb
60 watts = 0.06 kilowatts (kW)
on for 5 hours uses…
0.06 kW x 5 hours = 0.3 kWh
0.3 kWh x 14 p per kWh = 4.2 pence
4.2 p x 365 days = £15 a year
60w
Doesn’t sound like too much?

15. But it all adds up
with 10 bulbs in a house
that’s £150 a year.
10 low energy bulbs would use
£25

16. Cost of electricity:
10 mins5 mins 20 mins15 mins
Kilowatt hours (kWh):
We can work out what it costs to use
appliances for different lengths of time.
E.g. an 8,000 watt electric shower costs 42p to run for 20 minutes:
28p
1
42p
2 3
14p
A daily 20 minute
shower costs £153 a
year

17. Electric
shower
10 mins5 mins 20 mins15 mins
Kettle
2 h 4 hTV
28p
1
42p
2 3
14pCost of electricity:
Kilowatt hours (kWh):
Each box is to boil a full kettle
We can also compare different items.
8p

18. How did you do in our quiz?
How much electricity do the things in your home use?
1-5 watts
20-60 watts
1,000-1,600
watts
3,000+
watts

19. Do your own detective work
with an energy monitor.
For individual appliances:
What uses the most?
For the whole house:
How much do you use when
you think everything is off?

20. Or … look for an energy label
2,000 watts
(Often found on the back of an appliance)

21. What can you do to reduce your
energy use today?
… do it for Paul.

22. www.bigenergyrace.org
enquiries@bigenergyrace.org
© Global Action Plan. Charity registered in England and Wales number 1026148, and in Scotland number SC041260