EPA created the WAste Reduction Model (WARM) to help solid waste planners and organizations track and voluntarily report greenhouse gas emissions reductions from several different waste management practices. WARM is available both as a Web-based calculator and as a Microsoft Excel spreadsheet (461 kb WinZip archive).
WARM calculates and totals GHG emissions of baseline and alternative waste management practices—source reduction, recycling, combustion, composting, and landfilling. The model calculates emissions in metric tons of carbon equivalent (MTCE), metric tons of carbon dioxide equivalent (MTCO2E), and energy units (million BTU) across a wide range of material types commonly found in municipal solid waste (MSW).
NOTE |
ReCon and WARM were developed for purchasers and waste managers, respectively. ReCon calculates the benefits of alternative recycled content purchasing decisions. WARM, on the other hand, calculates the benefits of alternative end-of-life waste management decisions. Both tools calculate the benefits of an alternative scenario versus a business-as-usual scenario.
The WARM and ReCon tools are based on a life-cycle approach, which reflects emissions and avoided emissions upstream and downstream from the point of use. As such, the emission factors provided in these tools provide an account of the net benefit of these actions to the environment. This life-cycle approach is not appropriate for use in inventories because of the diffuse nature of the emissions and emission reductions contained in a single emission factor. |
WARM is periodically updated as new information becomes available and new material types are added. Users may refer to the model history to better understand the differences in among various versions of WARM. WARM was last updated August, 2005.
WARM now recognizes 30 material types, which are presented in the table below; their emission factors are available for viewing in units of MTCE or MTCO2E. Note that the emission factors represent the GHG emissions associated with managing 1 short ton of MSW in the manner indicated. GHG savings should be calculated by comparing the emissions associated with the alternative scenario with the emissions associated with the baseline scenario, as opposed to simply multiplying the quantity by an emission factor. For instance, the GHG savings of recycling 1 short ton of aluminum instead of landfilling it would be calculated as follows:
(1 short ton x -4.03 MTCE/short ton) — (1 short ton x 0.01 MTCE/short ton) = -4.04 MTCE
Material Types Recognized by WARM |
| Concrete Aggregate | Mixed Metals |
| Aluminum Cans | Mixed MSW |
| Branches | Mixed Organics |
| Carpet | Mixed Plastics |
| Clay Bricks | Mixed Recyclables |
| Copper Wire | Mixed Paper, Broad Definition |
| Corrugated Cardboard | Mixed Paper, Office Definition |
| Dimensional Lumber | Mixed Paper, Residential Definition |
| Fly Ash | Newspaper |
| Food Scraps | Office Paper |
| Glass | Personal Computers |
| Grass | PET |
| HDPE | Phonebooks |
| LDPE | Steel Cans |
| Leaves | Textbooks |
| Magazines/third-class mail | Yard Trimmings |
| Medium Density Fiberboard | |
Using WARM
WARM is available in a Web-based calculator format and as a Microsoft Excel spreadsheet. The WARM User's Guide will help you get up and running with the WARM software.
To download and open the Excel version of WARM, follow the directions below:
To download the zip file:
> | Save this file (warm.zip 461 kb WinZip file) to your hard drive. |
> | Open it and extract the warm.xls file to your hard drive. |
The installed program is a Microsoft Excel spreadsheet application. After you have installed the program, you may run the application:
Using Microsoft Excel 5.0
> | To run the WARM program, open the warm.xls file. |
> | Select the "Read Only" option. |
> | Then you may begin using the WARM application. |
Using Microsoft Excel 97 or 2000
> | To run the WARM program, open the warm.xls file. |
> | Select the "Enable Macros" option. |
> | You may then begin using the WARM application. |
IMPORTANT: In order for WARM to function, your Excel settings must be set to permit the use of macros. For instructions on adjusting your security settings and enabling macros, please refer to the WARM User's Guide.