A lot of people ask about harnessing human power in fitness centers, and there are some gyms, like Portland’s Green Microgym, that do that. Newer on the scene is ReRev, a company based in Florida that provides gyms with cardio equipment, including elliptical machines, to capture human power.

ReRev’s site is light on details about their machines, which are only available to dealers, but here’s the gist:

“ReRev™ retrofits cardio equipment to reroute the energy that is being emitted as a heat by-product. Instead of raising the temperatures inside the facility from the equipment and causing the air conditioning units to work harder, the energy is delivered to a central processing unit which converts the DC power to 240/208 Volt 60 Hertz AC. Each retrofit has a controller box which feeds back through a processor and into a central-grid tied inverter, tapping directly into the building’s electrical system — creating free electricity with no maintenance required.”

ReRev makes the system sound fancier than it is. The company hasn’t come up with a new way to turn human power into electricity, it’s only packaging the process uniquely. Bear in mind that you can do the same thing at home by following plans in The Human-Powered Home or those available from individual inventors.

Also, ReRev’s heat-reducing claim is a bit misleading. Of course, the machines will still produce heat (as will exercisers), though yes, a fraction of the energy that would have been emitted as heat will instead be directed to the DC generator.

The company’s site also mentions that exercisers are further motivated by watching meters on ReRev’s equipment that show how much electricity they’re generating for a facility.

Kansas University plans to install 15 of ReRev’s human-power-harnessing machines at their fitness center, as described in this article.