Energy, temperature & performance rates

Celsius and Fahrenheit; British thermal units per hour against watts, and kilowatts against horsepower, for plant nameplates; kilowatt-hours against therms for bills and fuel comparisons; lux against foot-candles for lighting levels; and spread rate in square feet per gallon against square metres per litre.

Whether the temperature is a reading or a difference, which is the one mistake in this family that never announces itself. A rise of 10 °C is a rise of 18 °F, not 50 °F, so a chart of degree days, a heat-loss calculation or a curing schedule converted with the wrong one is wrong by a factor rather than a rounding. Each page states which of the two it takes.

Heat loss, plant selection and lighting design, all of which need a building rather than a unit.