# Calculations and Assumptions

1. I will compost when eating in Benson, or one of the other campus cafe's; and bring other food waste to these places to be composted.

Notes: One person produces an average of 20 lbs of food waste per month (NRDC)

Assumptions for Calculations: 7 day week, 11 week quarter and 52 week year

2. I will use cloth or other reusable bags when I go shopping.

Notes: 100 billion plastic bags thrown away in the US each year.

US population in July 2008:  304059724

100  billion/population = 328 bags per person per year

1000 bags weigh 13.15 lbs, 328 bags weigh 4.313 lbs

savings of 4.312 lbs per year

Assumptions for Calculations: 7 day week, 11 week quarter and 52 week year Calculations made with 2008 population data because original source for this was a Wall Streett Journal article from 2008- our source below is an updated source link as this article link is no longer working.

3. I will recycle paper products, cans, and bottles.

Notes: 1 person generates 4.4 lbs of MSW per day

Nature  Conservancy's carbon footprint calculator estimates that by recycling all    materials "locally recyclable" you can save 0.5 tons CO2/year

Calculations for Assumptions: Use MD number of 0.000557075 MTCO2e per kWh to find carbon savings.

2,204.62262 pounds in one metric ton.

7 day week, 11 week quarter and 52 week year

4. I will carry a reusable water bottle.

Notes: Average of 4 bottles purchased per person per week.

At a recycling rate of 29%, giving up plastic bottled water diverts 2.84  bottles per week     from the waste stream (147.68 bottles per year).

1. 7 grams per bottle.
2. 7 g * 147.68 bottles = 1875.54 grams saved per year --> 4.135  pounds per year

Calculations for Assumptions: Assumes 4 bottles per  person per week.

29% recycling rate (EPA's given number for PET bottle recycling)

7 day week, 11 week quarter and 52 week year

5. I will replace one regular bulb with a compact fluorescent bulb.

Notes: Saves 32.85 kWh per year or 40.34  lbs CO2/year

Calculations for Assumptions: Use MD number of 0.000557075 MTCO2e per kWh to find carbon savings.

2,204.62262 pounds in one metric ton.

Assumes 2 hours a day of usage  (energy.gov number), or 730 hours/year

Assumes 60 W incandescent bulb and 15 W CFL

7 day week, 11 week quarter and 52 week year

6. I will wash clothes in cold water.

Notes: Energy Star appliance calculator: 1 wash per week --> 61 kWh/year.

With our  assumption of 1 wash every 2 weeks --> 30.5  kWh/year.

Washing in cold water saves 86% of energy-->  savings of 26.23 kWh/year or 32.21 lbs  CO2/year

Calculations for Assumptions: Assume Energy Star washer.

Use MD number of 0.000557075 MTCO2e per kWh to find carbon savings.

2,204.62262 pounds in one metric ton

7 day week, 11 week quarter and 52 week year

7. I will eat vegetarian one day a week.

Notes: 6 oz protein --> 0.158 kg serving

1. 0 kg CO2 (beef) - 2.0 kg CO2 (veg/tofu)
2. 37*52 = 487.24

Savings: 4.25 kg CO2/day --> 9.37 lbs CO2/day

1. 37*16 = 149.92

Calculations for Assumptions: Uses average USDA My Plate recommended protein numbers for adult men and women aged 19-30.  (Men 19-30 recommended serving: 6.5 oz. Women 19-30 recommended serving: 5.5 oz. Avg = 6.0 oz.)

Assuming students taking the pledge will be within age range of 19-30.

7 day week, 11 week quarter and 52 week year. 11 Mondays in a quarter and 52 Mondays in a year.

8. I will reduce vampire power by unplugging my printer, computer charger, and phone charger when not in use - or by using a power strip.

Notes: Printers: 12.78 kWh/year

Computer charger plugged into wall, not charging computer: 39.78 kWh/year

Computer charger plugged into wall, charging

Computer in sleep mode: 141.93 kWh/year

Phone charger plugged in, not charging phone: 2.34 kWh/year

Total: 196.83 kWh/year = 241.73 lbs CO2/year

Calculations for Assumptions: kWh based on average numbers for each item as listed on standby.lbl.gov website.

Total is sum of all device's standby averages.

Use MD number of 0.000557075 MTCO2e per kWh to find carbon savings.

2,204.62262 pounds in one metric ton

7 day week, 11 week quarter and 52 week year

9. I will reduce my showering time by five minutes.

Notes: Five minute showers use 10-25 gallons of water.

Reducing your showering time by five minutes is a reduction of 10-25 gallons regardless of total time.

Savings: 10-25 gallons per shower --> avg to 17.5 gallons Per day

Calculations for Assumptions: Assumes 1 shower per day

7 day week, 11 week quarter and 52 week year

10. I will turn off the tap while brushing my teeth.

Notes: 8 gallons per day

Calculations for Assumptions: Assumes daily teeth brushing.

7 day week, 11 week quarter and 52 week year

11. I will check my faucets, showerheads, and toilets for leaks and call (408) 554-4742 or my landlord when repairs are needed.

Notes: Faucets (leaking 1 drip per second): 3,000 gallons per year

Showerheads (leaking 10 drips per minute): 500 gallons per year

Toilet (running constantly): 200 gallons per day

Calculations for Assumptions: 7 day week, 11 week quarter and 52 week year

Uses total gallons from faucets, toilets, and showerheads

12. I will walk or bike short distances instead of driving.

Notes: Walking or biking 5 miles a week instead of driving saves 4.9 lbs of CO2 each week

Calculations for Assumptions: Use MD number of 0.000557075 MTCO2e per kWh to find carbon savings.  2,204.62262 pounds in one metric ton.

Speed: 10-11.9 mph AND under 10 mph

Weight: all weight ranges (144 or less, 145-174, 175 or more)

Car size: compact and midsize

7 day week, 11 week quarter and 52 week year

Source: Bike to Work Day