About those bike racks

About those bike racks
Source: Wikimedia

Source: Wikimedia

There's some evidence that those who commute to work by bike are healthier than those who drive a car.  That said, the first stop in people making fun of the LEED rating system is to talk about earning points by installing a bike rack.

I've noticed a strong correlation between people who make fun of bike racks & showers and those who drive everywhere.   They may like energy efficient buildings, but consider bike racks a pointless gesture.   Just thought I'd do the math to see what difference a bike rack (one that's used, at least) can make.  Here's the result:

The energy content of the gasoline used by the typical commuter each year is comparable to the energy used by his share of the building where he works.

Buildings have to be pretty close to net-zero energy before they'd save more energy through the building than by getting the employees to bike instead of drive.

The numbers:

  • According to CBECS, total source energy consumed by office buildings works out to 40,300 kBtu/yr per employee.
  • The mean commute distance for Americans is 18.8 miles; 81% commute alone by vehicle.  Assuming those commuting alone by car are doing so in a vehicle that gets the typical 22mpg, they consume 340 gallons of gas per year commuting.   Since gasoline has an energy content of 125 kBtu/gallon, this means their commuting will consume 42,500 kBtu/yr.
  • What about the energy for the shower?  That works out to about 700kBtu/yr to heat water. That's negligible compared with the gasoline being saved.

So providing conditions that induce 5% of your employees to commute by bike saves as much energy making the building itself use 5% less energy, and so on.   LEED v3 rewarded projects with 1 point (out of 110 maximum) for providing facilities for 5% of peak users; v4 reduced this to 2.5% of peak users.  Nationally, we're approaching just 1% of workers commuting regularly by bike, but in the top ten bike-friendly cities (those that promote bike use through paths, racks, and other facilities), that average is now 3%, with New Orleans at 3.6% (making us 5th in the nation!) and Portland leading the way at 5.9%.   And we can still aspire to the example of the Netherlands, where 30% commute by bike.     The last time we surveyed, 25% of EDR employees commuted regularly by bike.  Practically Dutch.

Maybe LEED for Existing Buildings Operations & Maintenance should offer points for achieved energy savings through regular bike commuting participation comparable to those for building energy performance: In a just world, getting 30% of your employees to commute by bike should earn you about 13 points!