WARM Excel User's Guide - Version 15
WARM Excel User's Guide - Version 15
Calculating Greenhouse Gas Emissions, Energy Impacts, and Economic Impacts with
the Excel Version of the Waste Reduction Model
What is the Waste Reduction Model?
The Waste Reduction Model (WARM) was created by the U.S. Environmental Protection Agency (EPA) to
help solid waste planners and organizations estimate greenhouse gas (GHG) emission reductions and
economic impacts from several different waste management practices.
WARM calculates GHG emissions, energy, and economic impacts for baseline and alternative waste
management practices, including source reduction, recycling, combustion, composting, and landfilling.
The model calculates emissions in metric tons of carbon dioxide equivalent (MTC02E), energy in millions
of BTUs (MMBTU), wage impacts, tax impacts, and labor hours supported across a wide range of
material types commonly found in municipal solid waste (MSW).
The user can construct various scenarios by simply entering data on the amount of waste handled by
material type and by management practice. WARM then automatically applies material-specific
emission and economic factors for each management practice to calculate the GHG emissions, energy
savings, and economic impacts of each scenario. Several key inputs, such as landfill gas recovery
practices and transportation distances to MSW facilities, can be modified by the user.
The GHG emission factors used in WARM are based on a life cycle perspective. The model
documentation describes this methodology in detail.
Who should use WARM?
WARM was developed for solid waste managers (from state and local governments and other
organizations) who want to calculate the GHG emissions and economic impacts associated with
different waste management options. Emissions and economic estimates provided by WARM are
intended to support voluntary GHG measurement and reporting initiatives and broader solid waste
planning. These initiatives include waste management components of state and local climate change
action plans, and other waste management projects for which an understanding of GHG emissions and
economic impacts is desired.
Using the Excel Version of WARM
Before using WARM, you first need to gather data on your baseline waste management practices and an
alternative scenario. In order to effectively use the tool, users should know how many tons of waste you
manage (or would manage) for a given time period under each scenario by material type and by
management practice. The model allows you to customize your results based on project-specific landfill
gas recovery practices, anaerobic digestion practices, and transportation distances. Note that you may
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WARM Excel User's Guide - Version 15
use default values if you are unsure of landfill gas recovery practices, anaerobic digestion practices
and/or transportation distances.
Instructions:
•	Click on the "Analysis Inputs" tab at the bottom center of the screen to open the input sheet.
Follow the instructions for Steps 1 and 2. This involves filling in the tables describing your
baseline and proposed alternative waste management scenarios. The "mixed" material types
are defined as the following:
o Mixed Metals: Aluminum Cans 35%, Steel Cans 65%
o Mixed Plastics: HDPE 40%, PET 60%.
o Mixed Electronics: Desktop CPUs 11%, Portable Electronic Devices 5%, Flat-Panel
Displays 23%, CRT Displays 44%, Electronic Peripherals 2%, Hard-Copy Devices 15%
o Mixed Paper (general): Corrugated Containers 48%, Magazines/Third-class Mail 8%,
Newspaper 24%, Office Paper 20%
o Mixed Paper (primarily residential): Corrugated Containers 53%, Magazines/Third-class
Mail 10%, Newspaper 23%, Office Paper 14%
o Mixed Paper (primarily from offices): Corrugated Containers 5%, Magazines/Third-class
Mail 36%, Newspaper 21%, Office Paper 38%
o Mixed Recyclables: Aluminum Cans 1.3%, Steel Cans 2.4%, Glass 6.0%, HDPE 1.2%, PET
1.8%, Corrugated Containers 56.8%, Magazines/Third-class Mail 7.3%, Newspaper 9.6%,
Office Paper 7.8%, Phonebooks 0.1%, Textbooks 0.6%, Dimensional Lumber 5.2%
o Food Waste: Beef 9%, Poultry 11%, Grains 13%, Fruits and Vegetables 49%, Dairy
Products 18%
o	Food Waste (meat only): Beef 46%, Poultry 54%
o	Food Waste (non-meat): Grains 16%, Fruits and Vegetables 61%, Dairy Products 22%
o	Mixed Organics: Food Waste 53%, Yard Trimmings 47%.
o	Mixed MSW- represents the entire municipal solid waste stream as disposed.
For more information on these mixed material weightings, please reference the model
documentation chapters specific to each material type.
•	Fill in the data requested in Steps 3-9. WARM will use the answers to these questions to
customize GHG estimates to reflect your waste management situation and location. For
example, you are asked for data on transportation distances and on your landfill gas recovery
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WARM Excel User's Guide - Version 15
systems, if applicable. If the requested data are not available, WARM will use the national
average defaults.
•	Step 10 allows you to customize your report, with your name, organization, and project period.
•	Once you have completed Steps 1-9 on the "Analysis Inputs" sheet, WARM will calculate the
GHG emissions, energy, and economic impacts attributable to the baseline and alternative
waste management scenarios you have specified. Emissions, energy, and economic impact
calculations are presented on separate output sheets, as described below. From the "Analysis
Inputs" sheet, click on a tab at the bottom of the screen for the results sheet you want to view
first.
•	The "Summary Report" sheet provides a concise report of GHG emissions, energy, or economic
results from the baseline and alternative waste management scenarios, as well as an estimate of
net emissions, energy, wages, taxes, or labor hours.
•	The "Analysis Results" sheet shows GHG emissions, energy, or economic results for each
scenario in the units selected. You can compare the total impact of the baseline and alternative
scenarios, or, if you want more detail, you can scroll down to view GHG emissions, energy, or
economic results by material type and management practice. The bottom table shows the
relative emissions, energy, wages, taxes, or labor hours difference between the alternative and
baseline scenarios for each material type and management pathway.
Assistance
If you need additional assistance with using WARM, please email orcrWARMquestions@epa.gov.
EPA530-R-19-003
May 2019
www.epa.gov/warm

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