Reference data
Constants behind the calculators, with sources. Retrieved and checked 2026-11-04.
Unit conversions
| Quantity | Equals |
|---|---|
| 1 kWh | 3.412 kBtu |
| 1 therm | 100 kBtu |
| 1 ton of cooling | 12,000 Btu/h = 3.517 kW thermal |
| 1 lb | 0.45359 kg |
| 1 short ton / 1 metric tonne | 2,000 lb / 2,204.62 lb |
| 1 MWh × 1 kg/kWh | 1 tonne CO₂e |
EPA greenhouse gas equivalency factors
| Item | Factor | Basis |
|---|---|---|
| Electricity, national average (used) | 3.94 × 10−4 t CO₂/kWh | 823.1 lb/MWh with 5.1% T&D loss |
| Electricity, national marginal (avoided) | 6.72 × 10−4 t CO₂/kWh | 1,405.3 lb/MWh |
| Gasoline | 8.887 × 10−3 t CO₂/gal | Federal Register (2010) factor |
| Diesel | 10.180 × 10−3 t CO₂/gal | Federal Register (2010) factor |
| Natural gas | 0.0053 t CO₂/therm (calculators use 0.005291) | 14.43 kg C/mmBtu |
| Passenger vehicle | 4.29 t CO₂e/vehicle/yr | 22.8 mpg, 10,917 miles/yr |
| Miles driven | 3.93 × 10−4 t CO₂e/mile | |
| Home energy use | 7.45 t CO₂/home/yr | electricity 4.798, gas 2.16, propane 0.24, oil 0.25 |
| Home electricity use | 4.798 t CO₂/home/yr | 12,194 kWh/yr |
| Urban tree seedling, 10 years | 0.060 t CO₂/tree/yr | |
| Wind turbine | 3,348 t CO₂/turbine/yr | 1.76 MW, 36% capacity factor |
| Coal railcar | 180.4 t CO₂/railcar |
Source: EPA calculations and references, page updated August 2026.
eGRID2023 total output CO₂ emission rates
EPA recommends eGRID subregion total output rates for location-based Scope 2. Rates are at the point of generation and exclude transmission and distribution losses. The U.S. average total output rate in eGRID2023 is 767.2 lb CO₂/MWh (770.9 lb CO₂e/MWh including methane and nitrous oxide).
| Subregion | Name | CO₂ lb/MWh | CO₂ kg/MWh |
|---|---|---|---|
| AKGD | ASCC Alaska Grid | 899.6 | 408.1 |
| AKMS | ASCC Miscellaneous | 520.5 | 236.1 |
| AZNM | WECC Southwest | 703.7 | 319.2 |
| CAMX | WECC California | 428.5 | 194.4 |
| ERCT | ERCOT All | 733.9 | 332.9 |
| FRCC | FRCC All | 782.3 | 354.8 |
| HIMS | HICC Miscellaneous | 1,123.4 | 509.6 |
| HIOA | HICC Oahu | 1,489.5 | 675.6 |
| MROE | MRO East | 1,397.3 | 633.8 |
| MROW | MRO West | 920.1 | 417.4 |
| NEWE | NPCC New England | 539.3 | 244.6 |
| NWPP | WECC Northwest | 631.7 | 286.5 |
| NYCW | NPCC NYC/Westchester | 864.5 | 392.1 |
| NYLI | NPCC Long Island | 1,180.7 | 535.6 |
| NYUP | NPCC Upstate NY | 242.1 | 109.8 |
| PRMS | Puerto Rico Miscellaneous | 1,543.1 | 699.9 |
| RFCE | RFC East | 596.9 | 270.7 |
| RFCM | RFC Michigan | 970.6 | 440.3 |
| RFCW | RFC West | 911.4 | 413.4 |
| RMPA | WECC Rockies | 1,036.6 | 470.2 |
| SPNO | SPP North | 862.0 | 391.0 |
| SPSO | SPP South | 872.0 | 395.5 |
| SRMV | SERC Mississippi Valley | 739.7 | 335.5 |
| SRMW | SERC Midwest | 1,239.8 | 562.4 |
| SRSO | SERC South | 842.3 | 382.1 |
| SRTV | SERC Tennessee Valley | 898.1 | 407.4 |
| SRVC | SERC Virginia/Carolina | 593.4 | 269.2 |
| US | U.S. national average | 767.2 | 348.0 |
Source: EPA eGRID summary data, eGRID2023, released January 2025. Look up your subregion with Power Profiler.
Hospital energy use intensity benchmarks
| Property type | Median site EUI (kBtu/ft²) | Median source EUI (kBtu/ft²) |
|---|---|---|
| Hospital (general medical and surgical) | 234.3 | 426.9 |
| Other / specialty hospital | 206.7 | 433.9 |
Source: ENERGY STAR. The hospital score model is based on the 2015 ASHE industry survey (148 hospitals before filters, 135 after) and uses staffed beds, FTE workers and MRI machines per 1,000 ft², plus heating and cooling degree days (technical reference).
Federal life-cycle cost discount rates
| Basis | Rate |
|---|---|
| Real discount rate (2025) | 3.0% |
| Nominal discount rate (2025) | 4.5% |
| Implied long-term inflation | 1.5% |
Source: NIST IR 85-3273-40, August 2025, effective until the 2026 edition. The calculated real rate was 2.2%, below the 3.0% floor in 10 CFR 436, so the floor applies.
Refrigerant global warming potentials (IPCC AR5, 100-year)
| Refrigerant | GWP |
|---|---|
| R-134a | 1300 |
| R-410A | 1923.5 |
| R-407C | 1624 |
| R-404A | 3943 |
| R-22 | 1760 |
| R-32 | 677 |
| R-513A (computed) | 573 |
| R-717 ammonia | 0 |
| R-744 carbon dioxide | 1 |
Blends are computed from component mass fractions (for example R-410A is 50% R-32 and 50% R-125). Other assessment reports differ; use the one your reporting program requires.
Anesthetic gas global warming potentials
| Agent | Range across published sources | Calculator default | Liquid density (g/mL) |
|---|---|---|---|
| Desflurane | 1,620 – 2,720 | 2,540 | 1.465 |
| Sevoflurane | 130 – 210 | 130 | 1.52 |
| Isoflurane | 510 – 565 | 510 | 1.50 |
| Nitrous oxide | 265 – 298 | 265 | n/a (gas, kg) |
Ranges as compiled in the MPOG sustainability toolkit. Densities are typical product-label values.
LEED thresholds and category points
Certified 40, Silver 50, Gold 60, Platinum 80 of 110 points. Category maximums for BD+C and O+M are on the LEED guide.