3.4 Electrical Energy and Power

3.4 ELECTRICAL ENERGY and POWER

Koh Hui Qin
5 Balau

Activity 3.10

Aim: To calculate the electrical energy consumption at home

Table 3.16

No. Electrical appliances Quantit Power Hours used Total energy usage /
kWh (A × B × C)
y (A) / kW in a day / h
0.4
(B) (C) 1.06
4.8
1 Electric rice cooker 1 0.4 1 1.725
1.3755
2 Television 1 0.212 5 32.5
0.315
3 Lamp 10 0.06 8 0.3674
0.08
4 Electric oven 1 2.3 0.75 3.38
5 Fan 7 0.0393 5 2.25
0.36
6 Air conditioner 5 1 6.5 0.06
0.8
7 Phone charger 6 0.07 0.75
49.4729
8 Hairdryer 2 1.1 0.167

9 Diffuser 1 0.08 1

10 Laptop charger 2 1.69 1

11 Washing machine 1 2.25 1

12 Home Internet router 1 0.015 24

13 Microwave 1 1.2 0.05

14 Vacuum cleaner 1 0.8 1

Total energy usage in a day / kWh

(a) Estimate the energy usage in kWh for 30 days
49.4729kWh x 30 days = 1484.187kWh

(b) Base on your home electricity bill, complete the following table (with the relevant
information):

ESTIMATED COST

Tariff block (kWh) Prorated block Rate (RM) Amount (RM)
(kWh)
0.2180 43.60
200 200(200 x 1.00000) 0.3340 33.40
0.5160 154.80
100 100(100 x 1.00000) 0.5460 163.80
0.5710 333.571
300 300(300 x 1.00000) 729.17

300 300(300 x 1.00000)

>900 584.187

Total

REAL COST

Tariff block (kWh) Prorated block Rate (RM) Amount (RM)
(kWh)
0.2180 43.60
200 200(200 x 1.00000) 0.3340 33.40
0.5160 154.80
100 100(100 x 1.00000) 0.5460 163.80
0.5710 328.33
300 300(300 x 1.00000) 723.93

300 300(300 x 1.00000)

>900 575

Total

(c) Compare the estimated cost for one month with the real cost of the electricity usage found in your
monthly bill.

Real cost = RM 723.93
Estimated cost = RM 729.171

Difference = RM 729.17 – RM 723.93
= RM 5.24

Discussion

1) Identify the electrical appliance in your home that consumes the highest electrical energy.

-From the table, the air conditioner in my house consumes the highest electrical energy.

2) Suggest steps to reduce the cost of electricity consumption in your home.

- Turn off the air conditioner when it is not in use
- Unplug the electrical appliance when it is not in use
- Buy a more efficient air conditioner in the future