Physics Activity 3.10 - Rebecca Low

Estimated Energy Consumption at Home

No. Electrical Appliances Quantity Power / kW Hours used Total Energy Usage
in a day / h (per day) / kWh
1. Air conditioner 1.0200
2. Air fryer 3 0.1700 2.0 0.3600
3. Fan 1.9040
4. Florescent lamp 1 1.8000 0.2 0.7920
5. Fridge 1.0944
6. Water heater 8 0.0340 7.0 6.6000
7. Water boiler 0.7300
8. Iron 11 0.0360 2.0 0.1800
9. Laptop charger 0.4050
10. Microwave oven 1 0.0456 24.0 0.5750
11. Phone charger 0.2520
12. Printer 1 3.3000 2.0 0.0004
13. Rice cooker 0.1350
14. WiFi Router 1 0.7300 1.0 0.7920
15. Table fan 0.1008
16. Bread toaster 1 1.8000 0.1 0.1600
17. Television 0.4920
18. Washing machine 3 0.0450 3.0 0.1620
15.7546
1 1.1500 0.5

2 0.0420 3.0

1 0.0021 0.2

1 0.4500 0.3

2 0.0180 22.0

2 0.0252 2.0

1 0.8000 0.2

1 0.0820 6.0

1 0.1080 1.5

Total energy usage in a day / kWh

a) Estimate the energy usage in kWh for 30 days.

Total energy usage = 15.75 kWh × 30

Total = 472.5 kWh

b) Based on your home electricity bill, complete the following table.

Tariff Block (kWh) Prorated Block (kWh) Rate (RM) Amount (RM)
200 200 (200 × 1.00000) 0.218 43.60
100 100 (100 × 1.00000) 0.334 33.40
300 0.516 52.63
102 Total 129.63

Total Energy Usage (based on the electricity bill) = 402 kWh

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

Tariff Block (kWh) Prorated Block (kWh) Rate (RM) Amount (RM)
200 200 (200 × 1.00000) 0.218 43.60
100 100 (100 × 1.00000) 0.334 33.40
300 172 0.516 88.75
Total 165.75

Estimated cost for one month = RM 165.75 Difference = RM 165.75 – RM129.63
Actual cost for one month = RM 129.63 Difference = RM 36.12

Discussion

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

The water heater used for bathing consumes the highest electrical energy in my house. It uses
6.6kW per day.

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

• Open the curtains from the morning to the evening so that natural light can enter the house
instead of switching on the lamps.

• Use energy saving appliances such as an energy-efficient refrigerator to reduce electricity
consumption.

• Take shorter showers to reduce the usage of water heaters.
• Switch off electrical appliances when they are not in use to conserve energy.