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This lesson delves into the cost and efficiency of household energy consumption. Students will learn how to determine energy usage for common appliances, calculate their efficiency, and explore practical strategies to reduce energy costs and environmental impact. Topics include understanding electricity meters, leveraging smart technology, and applying EnerGuide labels for energy-efficient choices. Through problem-solving exercises, learners will gain hands-on experience in evaluating their home energy use and applying knowledge to lower their bills and enhance sustainability.
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Reducing Our Electrical Energy Consumption Text 12.2 : Page 490-495
Agenda • Cost of Energy • Percent Efficiency • EnerGuide • Gizmo!
Learning Goals • By the end of this class we should be able to: • Determine Energy Consumption of appliances in our homes • Calculate Percent Efficiency of appliances in our homes • Plan ways to reduce energy usage in our homes
Where Do You Stand? or… Nothing in Life is Free! The Best Things in Life are Free!
Is Energy Free? • Every form of energy has some sort of cost associated with it • There not only economic cost, but also environmental costs • Best way to limit both your economic and environmental costs is to understand how, where and when you use electricity
The Cost in Your Home • Your house, apartment or townhome will have an electricity meter • Will have either a turning band or digital read that calculates the energy used in the home either monthly or bi-monthly
Reducing your Cost • Newer digital meters, also called smart meters, measure the energy hour and electricity is charged at different rates at different times • Therefore you can reduce your cost by putting your dishwasher on a timer to non “peak” times to lower your cost
How Energy is Measured • Energy usage of a house is measured in kilowatt-hours (kW•h) • i.e. the use of one kw in one hour • E= kW x H • kW= 1000 watts = 1000 joules per second
Calculating Energy Usage • To calculate the cost of using an electrical device you… • Calculate Energy Consumed : Multiply the energy consumed in kW•hby the number of hours used E consumed = kW•hx Hours Used
Calculating Energy Usage • To calculate the cost of using an electrical device you… • Calculate Cost: Multiply energy consumed by the cost per kW•h Cost = E consumed x cost per kW•h
Practise Problem If I use my vacuum 0.1 hours per day and the vacuum uses 38 kW•h, what is my cost per day to use the vacuum assuming I have a utility charge of 8.5 ¢ per kW•h? (page 492)
Percent Efficiency • Have you ever touched a light bulb for a long period of time after it has been lit? • What does it feel like? • HOT! This is a waste of energy • An incandescent bulb actually only uses about 5% of its input energy to create light
This Means…. 95% of the energy YOU PAY FOR is wasted in the form of HEAT!
Percent Efficiency • %efficiency= ( Eout/ Ein ) x 100%
Practise Problem Suppose a light bulb uses 780 J of input energy to produce 31 J of light energy. What is its percent efficiency? (Page 493)
Reducing Your Cost • You can use these devices when choosing appliances to reduce your cost environmentally and economically • These are advertised on the products on EnerGuidelabels • You can also purchase “green light bulbs” like fluorescence bulbs that convert 20% of its energy into light
EnerGuide • How much that appliance will use in a month or year of average use • Efficiency range when compared to other similar appliances • If energy star symbol there is it one of the most efficient appliances in its class