Normalization helps you compare month-to-month and year-to-year utility bills on a common “apples-to-apples” basis.
Normalization inserts a single year’s weather (degree days) into each year of utility bill data in order to provide valuable year-to-year weather adjusted usage comparisons.
Normalization modifies the data in a hypothetical “what if” scenario. The “what if” scenario inserts a designated year’s weather into every year’s utility bills. For example, if you chose to use 2010 as the standard year, the normalization process says, “What if every year’s weather had been exactly the same as 2010? What would my utility bill usage have been?”
The normalization processor adjusts every bill, every meter to the standard weather (degree days) of 2010 so that you can more accurately compare year-to-year usage. If 2011 normalized usage for a building is lower than the normalized 2009 usage, you know that the reduction is not due simply to milder weather in 2011 because the data for both years has been adjusted to standardized 2010 weather.
Lower normalized usage in 2011 means something other than the weather caused a reduction. Hopefully it is due to your energy management efforts (but of course it could be due to other independent factors such as fewer occupants or less hours of operation).
The normalization process begins with calendarized usage data and then it adjusts weather sensitive meters for the degree days in the user-selected weather normalization year.