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Teachers' Guide: Unit Conversions
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 Using the energy consumption values from the two "greenhouse gas emissions and energy consumption" tables
(from Part I and Part II of the "Getting Started" lesson) and the two worksheets provided, calculate the total
energy use of the house in common units (millions of BTUs/year) for the results in Parts I and Part II. Calculate total
carbon dioxide (CO_{2}) emissions from the house for the results in Parts I and II. Show how
the units should be cancelled in the formulas.

Based on your results from the Worksheets in the previous question, do the carbon dioxide emissions found in Parts I and II decline
from the results by the same percentage as the total energy use? If not, why would this be?
 Teacher Tools: Different forms of energy (gas, oil, etc.) have different emissions factors per useful unit of energy (BTU).
Thus, carbon dioxide emissions will decline more for a unit of oil saved than for a unit of natural gas saved, etc.

Do the emissions calculated on the worksheets agree with those on from the Home Energy Saver? (Yes/No). If not, why might this be?
 Teacher Tools: Assumptions for electricity emissions factors (based on mix of fossil fuels) are different in the HES model
than the value given in the worksheet.
Energy Unit Conversions Worksheet: A
Complete this worksheet with the information found in Part I (base home), showing how the units cancel to yield the proper
final units. Note: The home you are modeling will probably not have all four types of energy shown below! Just skip the ones that
are not relevant.
1. Convert raw energy to common units (millions of BTUs, MBTU): 

a. _______________ kWh x 3413 BTU/kWh x 1 MBTU/1,000,000 BTU 


= _______________ (fill in value and units) of electricity 

b. _______________ Therms x 100,000 BTU/therm x 1 MBTU/1,000,000 BTU 


= _______________ (fill in value and units) of natural gas 

c. _______________ Gallons Oil x 138,095 BTU/gallon x 1 MBTU/1,000,000 BTU 


= _______________ (fill in value and units) of heating oil 

d. _______________ Gallons LPG x 95,500 BTUs/gallon x 1 MBTU/1,000,000 BTU 


= _______________ (fill in value and units) of heating oil 

e. _______________ combine the preceding results to get total energy from all sources 

2. Convert MBTU of energy to greenhousegas emissions (pounds of carbon dioxide, CO_{2}) 

a. 1.2 lbs CO_{2}/kWh x 1 kWh/0.003413 MBTU x __________ MBTU of electricity 


= _______________ (fill in value and units) CO_{2} from electricity 

b. 12 lbs CO_{2}/therm x 1 therm/0.1 MBTU x __________ MBTU of natural gas 


= _______________ (fill in value and units) CO_{2} from natural gas 

c. 22.384 lbs CO_{2}/gallon oil x 1 gallon/0.138095 MBTU x __________ MBTU of heating oil 


= _______________ (fill in value and units) CO_{2}from heating oil 

d. 12.805 lbs CO_{2}/gallon LPG x 1 gallon/0.0955 MBTU x __________ MBTU of LPG 


= _______________ (fill in value and units) CO_{2}from LPG 

e. _______________ Combine the preceding results to get total CO_{2} from all sources of energy 
Energy Unit Conversions Worksheet: B
Complete this worksheet with the information found in Part II (efficient home). Show how the units cancel to yield the proper final
results. Note: The home you are modeling will probably not have all four types of energy shown below! Just skip the ones that are
not relevant.
1. Convert raw energy to common units (millions of BTUs, MBTU): 

a. _______________ kWh x 3413 BTU/kWh x 1 MBTU/1,000,000 BTU 


= _______________ (fill in value and units) of electricity 

b. _______________ Therms x 100,000 BTU/therm x 1 MBTU/1,000,000 BTU 


= _______________ (fill in value and units) of natural gas 

c. _______________ Gallons Oil x 138,095 BTU/gallon x 1 MBTU/1,000,000 BTU 


= _______________ (fill in value and units) of heating oil 

d. _______________ Gallons LPG x 95,500 BTUs/gallon x 1 MBTU/1,000,000 BTU 


= _______________ (fill in value and units) of heating oil 

e. _______________ combine the preceding results to get total energy from all sources 

2. Convert MBTU of energy to greenhousegas emissions (pounds of carbon dioxide, CO_{2}) 

a. 1.2 lbs CO_{2}/kWh x 1 kWh/0.003413 MBTU x __________ MBTU of electricity 


= _______________ (fill in value and units) CO_{2} from electricity 

b. 12 lbs CO_{2}/therm x 1 therm/0.1 MBTU x __________ MBTU of natural gas 


= _______________ (fill in value and units) CO_{2} from natural gas 

c. 22.384 lbs CO_{2}/gallon oil x 1 gallon/0.138095 MBTU x __________ MBTU of heating oil 


= _______________ (fill in value and units) CO_{2}from heating oil 

d. 12.805 lbs CO_{2}/gallon LPG x 1 gallon/0.0955 MBTU x __________ MBTU of LPG 


= _______________ (fill in value and units) CO_{2}from LPG 

e. _______________ Combine the preceding results to get total CO_{2} from all sources of energy 
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