3.06 Energy consumption of appliances

Express the following rates in watts:

Calculate how many joules are in the following. Use the fact that 1\text{ kWh}=3.6 \times 10^{6}\text{ J} and express your answer as a basic numeral.

Calculate how many kilojoules are in the following:

An appliance consumes energy at a rate of 1200 \text{ W}. If it runs for 29 seconds, calculate how many joules of energy it uses.

5.4\text{ kWh} is used by an appliance for 10 hours. How many kilowatts is this?

An appliance consumes energy at a rate of 0.59\text{ kW} for 8 hours. How much energy is this in \text{kWh}?

An appliance consumes energy at a rate of 0.23\text{ kW}. If the appliance consumes 2.07\text{ kWh}, how long is the appliance in use?

Find the number of hours each appliance has been operating to the nearest hour:

To work out the power in kilowatts \left( \text{kW} \right) produced by a bank of solar panels we use the following formula:

\text{Power } = \dfrac{\text{Number of panels} \times \text{Power output of each panel}}{1000}

Calculate the energy consumption for the appliances in the table below:

A washing machine is used for a total of 16 hours per month. Its monthly electricity cost is \$1.8648.

If 1\text{ kWh} costs \$0.185, how many kilowatts does the appliance use each hour?

Valentina uses a 550-watt iron for 8 hours every week.

Gwen uses a 900-watt microwave for 8 hours every day.

A microwave oven uses 0.95 kilowatts each hour. In a month, this appliance runs for 8 hours.

If electricity costs \$0.185\text{ per kWh}, what is the cost of this appliance for the month?

A household wants to find the cost of running their appliances in the kitchen. The appliances, the amount of watts consumed, and the amount of time they are active in a day are given in the table below:

The average rate for electricity is \$0.14 \text{ per kWh}. Find the average running cost of the kitchen appliances in one day.

Calculate the running cost for a single day use of each of the following appliances given that the average rate for electricity is \$0.12\text{ per kWh}:

Kathleen, Jack and Aaron live at different houses and have different electricity plans. The cost of electricity for each of them is shown in the table below:

Calculate the electricity cost to run the following appliances:

Given that there are 365 days in a year, find the running cost for each of the following for one year:

Amy is looking to purchase a new coffee machine for the office. She is deciding between 2 models that cost the same, the 1050-watt Cuppa Joe brand and the 800-watt Java Juicer brand. The coffee machines will be on for approximately 0.6 hours a day. The average rate for electricity is \$0.17 \text{ per kWh}. Assume there are 365 days in a year.

Frank needs a new washing machine. He is deciding between 2 models that cost the same, the Washington brand and the Loaded brand. The washing machines both use different amounts of power depending on the selected cycle. The length and power required for each cycle are given in the tables below:

Frank knows he performs around 60 loads of washing a year. The average rate for electricity is \$0.12 \text{ per kWh}.

Emma is upgrading all 9 light globes in her house to energy saving globes. Her current globes are 60 \text{ W} and the energy saving globes are 9 \text{ W}. Each globe will be used for approximately 1750 hours a year. The average rate for electricity is \$0.16 \text{ per kWh}.

A television is used for 4 hours a day and consumes energy at a rate of 320 \text{ W}. The average rate for electricity is \$0.14 \text{ per kWh}. Assume that there are 365 days in a year.

Gwen is searching for a new dishwasher for her restaurant. Her 2 options are the 2000-watt Power Clean brand for \$1000 and the 1500-watt Sparkle Sparkle brand for \$1400. The dishwasher will be used for approximately 2 hours a day. The average rate for electricity is \$0.16 \text{ per kWh}. Assume that there are 365 days in a year.

Harry uses his computer for 2.5 hours a day. It requires 135 \text{ W} to operate. Nadia is using a different model of computer for 12 hours a day that requires 70 watts to operate. The average rate for electricity is \$0.15 \text{ per kWh}. Assume that there are 365 days in a year.

Sophia and Neville are comparing heaters. Sophia's heater requires 610 \text{ W} and takes 1.5 hours to heat their room. Neville's heater requires 1190 \text{ W}, but it takes only 0.6 hours to heat their room. They both have the same average rate for electricity, which is \$0.13 \text{ per kWh}.

A family received an electricity bill of \$405 in the last quarter, with electricity charged at 22.5 cents per \text{kWh}. They are considering installing a new 2.8\text{ kW} air conditioning unit and estimate that they’ll use it for 9 hours each day.

A family is comparing the price and energy consumption of dishwashers in a store. They expect that over a year, they will use the dishwasher for 320 loads. They find a 2-star rated dishwasher for \$320 that uses 1.9 \text{ kWh} per load and compare this to an energy saving 4-star rated dishwasher which costs \$460 and uses 1.1 \text{ kWh} per load. 1 \text{ kWh} costs 17 cents.

An office manager is comparing the price and energy consumption of televisions. They expect that over a year, they will use the television for 6 hours per day. They find a 3-star rated television for \$750 that uses 274 \text{ kWh} per year, and compare this to an energy saving 9-star rated television which costs \$1083 and uses 72 \text{ kWh} per year. 1 \text{ kWh} costs 17 cents.

Sophia’s family just installed a 25 \text{ W} Compact Fluorescent Lamp (CFL) bulb in their kitchen. It gives off the equivalent amount of light of a 100 \text{ W} incandescent bulb. They use the light for 5 hours each day. Peter's family has a 100 \text{ W} incandescent bulb in their kitchen, and use it from 6 pm to 10 pm each day. 1 \text{ kWh} costs 20.9 cents.