Elevator rides represent a significant amount of the total energy used in buildings today. The energy it takes to travel just one floor is small, roughly equivalent to the amount of energy needed to charge a portion of a cell phone battery (about 2.5 Wh). But the accumulative effect of taking the elevator several times per day and all year long can add up to the equivalent of being able to run your plasma TV for two days straight!
According to elevator manufacturer Kone, a typical hydraulic elevator in a three-story office building uses 3,800 kilowatt hours per year, or about as much as the average American home uses in four months. A traction elevator in a 10-story building might use about five-and-a-half times as much energy!
A 20-floor roundtrip consumes 100 Wh, approximately the same energy used in 30 minutes by a desktop computer and monitor. However, riding in the elevator alone each time for two round trips per day, or 200 Wh of consumption, is the equivalent energy needed for an hour’s worth of operation of the desktop/monitor of a 37-inch plasma TV.
As an example, let’s take a 20-story office building with a bank of 12 elevators. By taking two of the 12 elevators offline, passengers wait longer and trips are consolidated. Let’s use a conservative estimate of one trip every five minutes, or 20 an hour. Of course, not everyone is going to the 20th floor, so let’s assume that the floors are evenly distributed in terms of visitors and use the 10th floor as a case study. In that instance, 25 Wh is saved per trip, and 500 Wh is conserved per hour.
That’s the equivalent of
- eight 60-watt bulbs.
- a desk heater turned on its lowest setting for an hour.
- the energy produced by three 180W solar panels in 60 minutes in bright sunlight.
Though the individual savings from choosing the stairs instead of the elevator may be small, this shows that behavior modification can be the cheapest form of energy efficiency. One step that may not result in huge savings today, once repeated and coupled with other steps may result in bigger savings over time. And if you have to ride the elevator, hold the door for the next passenger to join you.