Quiz: What You Don’t Know About Energy Efficiency


Hudson Passive House (Photograph courtesy BASF)

You know that poor insulation makes for a drafty, energy-wasting home, but how much do you really know about the true potential of energy efficiency?

Quiz by Christina Nunez

How much of the energy in an average fossil fuel-burning power plant is lost as waste heat?

  • About 15 percent
  • About 25 percent
  • About 45 percent
  • About 65 percent

The average fossil fuel plant converts about 33 percent of the energy going in to power going out, an efficiency rate that has not changed significantly over the past few decades, according to the U.S. Environmental Protection Agency. (See also: “The Global Electricity Mix”)

A typical furnace fan can be a drain on household efficiency, using an average of 1,000 kilowatt hours per year. About what percentage of an average home’s annual electricity use does that represent?

  • 2 percent
  • 5 percent
  • 10 percent
  • 15 percent

An average furnace fan can account for about 10 percent of an entire annual home’s electricity consumption. Standards set to take effect in the U.S. in 2019 would cut furnace fan energy use by about 40 percent. (See also: “Six Stealthy Energy Hogs: Are They Lurking in Your Home?”)

How much of energy in the fuel for your car is used to move it down the road?

  • About one quarter
  • About half
  • About two thirds
  • Nearly all of it

About 14 to 30 percent of the energy that goes into your car actually propels it. The bulk is lost as heat, friction, and combustion in the engine. (See related story: “Supercomputing Power Could Pave the Way to Energy-Efficient Engines”)

Which type of light bulb is the most efficient at converting energy into light?

  • Incandescent
  • CFL
  • LED

LED, or light-emitting diode, light bulbs produce an average of 85 lumens per watt of power used—about 15 percent more than CFLs and more than five times as much as an incandescent. Overall, efficient light bulbs like LEDs and CFLs use about 80 percent less energy than traditional incandescents. (See also: Light Bulb Savings Calculator)

An international coalition has set a global fuel economy target of 4 liters per 100 kilometers (58.8 miles per gallon) by 2030. Where does the current global average stand?

  • 12 liters/100km (20 mpg)
  • 10 liters/100km (24 mpg)
  • 7 liters/100km (33 mpg)
  • 5 liters/100km (47 mpg)

As of 2011, the average fuel economy of light-duty vehicles in countries surveyed by the Global Fuel Economy Initiative was 7.2 liters per 100 kilometers (32.7 miles per gallon).

The Obama administration set the first-ever fuel efficiency standards for heavy-duty trucks in 2011. Such vehicles account for 4 percent of U.S. on-road traffic, but how much of its fuel consumption?

  • 10 percent
  • 20 percent
  • 30 percent
  • 40 percent

Heavy-duty vehicles, which haul 70 percent of U.S. domestic freight, account for 20 percent of on-road fuel consumption.

When you first turn on an air conditioner in a warm room, it's best to set the temperature as low as possible so that it gets cool faster.

  • True
  • False

Set your thermostat to the temperature you want. Setting it lower won't make the room cool any faster, and it might lead to a higher energy bill.

What is Jevons' Paradox? The idea that:

  • Decreased efficiency leads to increased efforts to conserve resources
  • Decreased efficiency leads to increased waste of resources
  • Increased efficiency leads to better management of resources
  • Increased efficiency leads to increased consumption of resources

The controversial Jevons Paradox, or "rebound effect," says that as energy efficiency goes up, making a resource more cost-effective, the overall consumption goes up as well, canceling out any savings.

The energy intensity of the U.S. economy—how much energy it consumes per gross domestic product dollar—went down by how much between 1950 and 2011?

  • 38 percent
  • 48 percent
  • 58 percent
  • 68 percent

According to the Energy Information Administration, "greater efficiency and structural changes in the economy" led to a 58 percent decline in energy consumed per dollar of GDP.

In a 2014 ranking of countries based on energy efficiency, Germany came in first, followed by which country?

  • China
  • Italy
  • Japan
  • France

Italy ranked second in the American Council for an Energy-Efficient Economy's list of 16 economies, thanks in part to its stringent fuel economy standards.





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