The fuel efficiency of an electric car is measured in kilometres per kWh. It is a measure of how far the car can travel on a single unit of electricity. Calculating the fuel efficiency or mileage of ...

A very inefficient device will waste most of its input energy. The efficiency of a device is the proportion of the energy supplied that is transferred in useful ways. The efficiency can be calculated ...

Devices are designed to waste as little energy as possible. This means that as much of the input energy as possible should be transferred into useful energy stores. A very efficient device will waste ...

There are roof shapes and ratios that maximize heat retainment and energy efficiency and, interestingly, ancient Italian architects and builders seemed to know it, too. While serving as a visiting ...