Comparing energy usages throughout different times can be tricky even when the durations are identical and the usage takes place during the same periods of different years. For example, the electricity consumed by a building during March 2014 can be greatly superior to that consumed by the same building March 2015: if March 2015 was hotter than March 2014 and if the electricity is partially utilized to power up Air-conditioners, then it does explain, at least partially, the reason why more electricity was consumed in March 2015 than in March 2014.

Given that we frequently need to compare energy usages (for example to assess whether or not the implementation of an energy conservation program has yielded any savings), it’s important that the problematic of the weather variations is taken into consideration. This is called weather normalization.

In short, rather than compare last year’s usage to this year’s usage, when we use weather normalization, we compare how much energy we would have used this year to how much energy we did use this year. This is called “Usage Avoidance” or “Cost Avoidance” (if comparing costs).

The next question is, how do we figure out how much energy we would have used? That is where weather normalization comes in. First, we select a period of utility usage to which we want to compare future usage. This would typically be the year before an alternative energy program is started, the year before a retrofit is installed, or the year before an energy contractor, were hired, or just some year in the past that we want to compare current usage to. We will call this year the Base Year.

Degree Days (as applicable to the concerned location) for the Base Year periods are then calculated. Base Year usage and Degree Days are then normalized by number of days. Normalizing by number of days (merely, dividing by number of days) removes any noise associated with different consumption period lengths.

Our platform allows the customer to weather normalize all weather-linked consumptions (refer to AnalyFeed). These normalized consumptions are essential to all retrofit projects’ Measurement & Verification (Monitoring & Targeting)