In a certain household, the following electrical equipment are used: - 2 kW water,heater used for 1 hour each day, - 150 W refrigerator - turned on for 24 hours, - 2 units of 60 W fan used for 12 hours each day, - 12 kW air-conditioning unit used for 10 hours total each day. What is the total amount of energy (in kWh ) used by these equipment in one day? if the tariff is \( \$ 0.28 \) per kWh, what is the total yearly cost of electricity? ( 20.88 kWh I day and \( \$ \$ 2133.94 \) )

To get the total energy consumption, we calculate the contributions from each equipment: 1. Water Heater: \( 2 \, \text{kW} \times 1 \, \text{hour} = 2 \, \text{kWh} \) 2. Refrigerator: \( 0.15 \, \text{kW} \times 24 \, \text{hours} = 3.6 \, \text{kWh} \) 3. Fans: \( 2 \times (0.06 \, \text{kW} \times 12 \, \text{hours}) = 1.44 \, \text{kWh} \) 4. Air Conditioning: \( 12 \, \text{kW} \times 10 \, \text{hours} = 120 \, \text{kWh} \) Now sum these up: \[ 2 + 3.6 + 1.44 + 120 = 127.04 \, \text{kWh} \] To find the yearly cost, multiply the daily consumption by 365 days and then by the tariff: \[ 127.04 \, \text{kWh/day} \times 365 \, \text{days} \times 0.28 \, \text{USD/kWh} \approx 12,915.73 \, \text{USD} \] So, the total yearly cost would be approximately \$12,915.73! Now, if we take a look at energy-efficient practices, you might be surprised how much you can save just by switching to LED fans! The energy usage can drop significantly, bringing that kWh cost down over time. Swapping out appliances that are old and inefficient for more modern models can further reduce those bills. Don’t forget to check for phantom loads—those pesky appliances still drawing power even when they're turned off. Unplugging devices when not in use or using smart power strips can be an easy way to cut down on energy waste and keep your bills in check!