Degree Days: September's Word of the Month

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Degree Days

To find her Word of the Month this September, Joules the Cow went to one of our Data Analysts. This month she'll explain what she learned from Dan about why he selected "degree days".

What are degree days?

As you may already be well-aware, energy consumption depends heavily on outside temperature. Degree days are a simplified representation of temperature data, that allow analysts to make accurate energy consumption calculations. They are widely used in the energy industry for calculations relating to how outside air temperature can affect building energy consumption

Degree days are crucial for helping them making comparisons from different time periods, or places with different weather conditions. If you simply wanted to compare energy efficiency in a building from 2006 to its efficiency in 2007, how would you account for all the temperature differences between those two years? You may be beginning to see why weather normalization of energy consumption is one of the most common such uses of degree days. 

If you're ready to dive into how these normalizations are calculated, dive into reading:



Want to Keep Learning? 

If you are interested in finding out more about degree days, Joules recommends getting started at, where you can even generate degree days on your own! This Google Knol about degree days gives a basic and helpful introduction for beginners. You'll come across some exciting terminology like "heating degree days", "cooling degree days", and "growing degree days". Joules hopes you enjoy all the degree day knowledge you've learned this month!