This article was originally published in 2013, Lessonface's first year of existence. We were still using CamelCase capitalization on the name. The math should remain more or less the same. Two years ago, we became a Public Benefit Organization and further strengthened our commitment to sustainability. Read more about the Lessonface mission >>

At LessonFace we think a good bit about the greater implications of our service, and one of the issues that occupies the top of our minds is how lifestyle changes our energy dependency. So, we asked noted energy expert Dan Fischl, Ph. D, to compare the energy usage of driving to a traditional lesson across town vs. meeting with an expert teacher on LessonFace.

Conclusion: LessonFace uses 612.7 times less energy

We found these results pretty staggering, and honestly more compelling than we anticipated. And this is the difference for a trip across town – if LessonFace sessions are able to stand in for flying somewhere to meet a master teacher in person, the difference would be even more phenomenal. Calculations follow in case you want to see the math.

LessonFace Energy Savings

Computer-based LessonFace energy consumption

A typical laptop uses 20-90 watts.

Assumptions: Both teacher and student are using laptops for one hour. When they are on, each laptop consumes electricity at a rate of 55 watts. After a one-hour lesson, each laptop will consume 55 Whr of energy (55 watts X 1 hour). The two laptops will consume a total of 110 Whr (0.11 kilowatt-hours).

Traditional lesson energy consumption

According to an Environmental Protection Agency formula, 33.7 kilowatt hours of electricity is equivalent to one gallon of gasoline.

Assumptions: The instructor or student drives 40 miles round trip with a car that gets 20 miles per gallon. This means two gallons of gasoline will be consumed. This is equivalent to 67.4 kWhr of energy.

If you want to figure out how much energy consumption you could save by taking lessons with LessonFace instead of driving, just divide your round trip number of miles traveled by your vehicle’s fuel efficiency (it may be higher or lower than 20 miles per gallon), and then multiply that number (the number of gallons of gas you use for the commute) by 33.7 to get the total amount of energy used.

Conclusion: LessonFace uses 612.7 times less energy (0.11 X 612.7 = 67.4)

LessonFace Greenhouse Gas Emissions Savings

Estimates were obtained by using the Carbon Trust conversion factors.

Computer-based LessonFace greenhouse gas emissions

Page four of the above reference states that 0.5264 kg CO2 is equivalent to one kilowatt hour. Carbon dioxide released for the electricity generated for the one hour computer-based lesson is 0.058 kg (0. 5264 X 0.11 = 0.058).

Traditional lesson energy consumption

Page five of the above reference states that for a medium-sized car, 0.3413 kg of CO2 is released for every mile driven. The 40 miles driven to and from the lesson would release 13.65 kg of CO2 (0.3413 X 40 = 13.65).

Conclusion: 235 times less CO2 is released with LessonFace (0.058 X 235 = 13.6)

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