Home Energy Audit - ELECTRICITY USE
Objectives
● Conduct an energy audit/survey of electrical appliances in your home, in terms of the energy used and the costs
involved.
● Determine the amount of energy used by different appliances.
● Interpret a monthly electric bill.
● Make calculations and conversions relating to energy use.
● Increase your understanding of energy units such as watts, volts, amps, and kilowatt-hours.
● Design and implement a specific strategy or conservation plan that will lead not only to a reduction in the amount of
electricity that you use, but also to a lower monthly cost.
Introduction
Electrical consumption has gone up in the United States over the last 50 years for a number of reasons, including
increased per capita demand and commercial and industrial demand from economic expansion. While the number of
Americans grew by 87 percent from 1950 through 2000 (from under 150 million to almost 280 million), their energy
consumption expanded by a much greater 194 percent.
At the same time, some traditional sources of fuel for electrical generation have stagnated or even fallen. In the energy
mix today, coal is the dominant fossil fuel for the production of electricity-and growing. In 2001, 51.7% of our electricity
was from coal. Petroleum now supplies very little electricity in the U.S., less than previously. Natural gas supplies about
16% of our electricity. Natural gas supply and demand were in relative balance in the United States until the mid-1980s,
when a production-consumption gap developed. As a result, in 2001 domestic production of natural gas was 19.7 trillion
cubic feet, consumption was 22.2 trillion cubic feet, and imports were 3.98 trillion cubic feet.
Nuclear electric power did not exist in this country until 1957. The new industry expanded rapidly until the 1979 accident
at Three Mile Island in Pennsylvania and the Chernobyl catastrophe in Ukraine in 1986. As fewer new units came on line
and old units began to shut down, the number of operable units fell to 104 in 2001. Today about 21% of our electricity is
from nuclear power, a portion currently in a downtrend.
Our personal use of electricity is very small when compared to the total used in the United States today, and personal
consumption of fuels is equally small. But as you have seen in other investigations, when the small amounts used by
individuals are added up, they become a very significant value for a large population. Personal decisions about how much
energy to use or save and which sources to depend on are very significant.
**Before Starting - YOU WILL NEED THIS INFORMATION**
Acquire a copy of your home’s electric bill (any one from the last six months will work). Attach a screenshot or picture of
the bill below (remove/cross out identifying information). Price paid per kWh and Electric provider need to be visible.
Data/Observations/Analysis
Before starting this activity, make a list of what you consider to be the top 10 items in your home, in terms of their
electricity consumption, going from the most to the least.
1. Carrier Infinity 16 ACU 6. Aroma Arc-5200sb
2. PC (video editing) 7. Amazon Basics 500-Watt Ceramic heater
3. Whirlpool - WDF330PAHS 5 8. Vitamix A2500
4. Macbook Pro 2020 9. ninja dz201
5. Whirpool Microwave 10.
1.) On the Home Electrical Use chart below, choose 15 appliances used around your home daily. I have included a
few examples, but you do not have to use them. You can remove/replace those included. Please include the
make/model so we can compare class data.
2.) Record the amount of time you use each appliance each day. If an appliance is used a few times a week or less,
prorate it to daily use. (3 hours a week: 3 hours/7 days = 0.43 hours per day.
3.) Determine their power (in watts) by multiplying the volts by the amps on the appliance label. Convert the watts to
kilowatts and multiply by the time used to get kilowatt-hours/day, then multiply to get the cost per appliance per
day and the cost per year.
4.) Include your calculations on a separate sheet of paper.
5.) Construct an appropriately labeled graph depicting the annual energy use of the appliances you chose.
Home Electrical Use
Appliance Power Power Number of Energy/day Cost Cost
(W) (kW) hours/day (kWh/day) Per Day Per Year
Carrier Infinity 6x
16 ACU
Washing machine
Dryer
Whirlpool -
WDF330PAHS 5
Refrigerator
Coffee maker
Toaster
Desktop
computer
Laptop computer
Amazon Basics
500-Watt
Ceramic heater
Vitamix A2500
ninja dz201
Aroma
Arc-5200sb
Vacuum cleaner
TOTALS
1. Now take a look at your completed table and see how it compares to what you thought would be the top ten, most to
least.
a. How did you do?
b. Are you surprised?
2. If you had to eliminate four electrical items from your home, which would they be and why?
I would eliminate my TV, toaster, hair dryer, &
3. Make an argument for keeping four electrical items that you consider to be essential in your home. Explain your
reasoning.
4. Number of occupants in your home: 4
Use the following equivalences in calculating answers to the exercises below. Be sure to show the steps of your work,
including set-ups and proper units, as well as final answers.
Conversion Factors 1 pound bituminous coal = 12,000 BTU
1 kWh = 3.41 x 103 BTU (British Thermal Units) 1 barrel oil = 5.6 x 106 BTU = 5.91 x 109 J
1 BTU = 2.93 x 10-4 kWh 1 ft3 natural gas = 1,030 BTU = 1.09 x 106 J
1 BTU = 1,055 J (joules) 1 g 235U = 4.0 X 107 BTU = 4.22 x 1010 J
12,000 BTU = 3.52 kWh = 1.27 x 107 J
1. How much electrical energy do you consume each day, on average? How much would that be each year?
2. Suppose the electricity in your region was supplied by the burning of natural gas.
a. How many cubic feet of natural gas is needed to support your energy lifestyle?
b. 1,000 ft3 of natural gas contains about 20.2 kg of methane. When burned completely it produces 122 lb of carbon
dioxide. How much methane would you consume in one year, and how many pounds of carbon dioxide would you
produce?
3. Suppose coal were used in the generators instead of natural gas.
a. How much coal would be burned to provide your energy?
b. When coal is burned, about 2.3 lb of CO2 is produced for every kilowatt of electrical energy consumed. How
much carbon dioxide would be produced by your yearly electricity use?
4. Suppose the electrical power was produced by nuclear power. How much uranium would be needed for your yearly
consumption?
5. Calculate comparative costs.
a. The cost for U308 the primary nuclear reactor fuel, is $10.15 per pound, or about $0.022 per gram. What would be
the cost of the uranium to generate your electricity?
b. Coal costs about $24.38 per ton, and the cost of natural gas for electric utilities, on the average, is about $4.67 per
1,000 cubic feet. Calculate the cost of these two fuels to produce your yearly electricity.
6. Compare the pros and cons of using these fuels to produce electricity on a large scale.
a. Is the cheapest fuel necessarily the best choice? Explain your reasoning in economic, social, and environmental
terms.
b. Discuss in some detail extraction, processing, transportation, burning, waste products, and health and safety
aspects of the problem.
7. Outline five ways to reduce the use of electrical power in your everyday life.
