There are several factors that can result in "Not Available" for Weather Normalized Site and Source EUI. But first, make sure you have a value for Source EUI and Site EUI, because if you don't, you will never get a value for Weather Normalized Site/Source EUI. If that is the case, go to the Goals tab click the “NA” for Source EUI to view a detailed reason.
When we calculate Weather Normalized energy, each fuel is normalized separately, then added together to get a total. If we are unable to normalize each individual fuel (e.g. the electricity, gas, and oil), then you won’t have Weather Normalized Site or Source EUI. However, normalized values are available for Electricity and Gas individually in Reporting, so you might be able to get something even if you don’t have Weather Normalized Site/Source EUI.
If you have Source EUI, but not Weather Normalized Source EUI, it is most likely for one of these reasons:
- You have monthly meter entries that cover more than 65 days. For data you enter with monthly bills (e.g. Electricity, Gas, and Steam), we cannot normalize if you have one bill that covers more than 65 days. The process of weather normalization relates monthly energy use to monthly temperatures. When one bill covers more than two months, we do not have a way to line up how energy use changed when temperature changed. For example, if your electric bill covers August, September, and October, we have no way of knowing if you used more energy to air condition in August, when it was hotter. Therefore, we cannot accurately normalize when one monthly bill covers more than 65 days.
- You receive deliveries in fewer than 5 different calendar months over the last 2 years*. For data you enter for bulk meters (e.g. oil or wood), we cannot normalize if you have deliveries in fewer than 5 months over a 2-year period. In our calculations, energy associated with a bulk meter is assumed to be used in the month that it was received because most buildings that heat with these types of fuel receive a delivery during each month of the winter. There are rarely deliveries in summer months, because that fuel is not used in the summer (i.e. a value of 0 can be assumed). However, in order to see a relationship between energy and temperature we will need to have at least 5 data points over the last 2 years. Otherwise, we cannot see how energy changed due to temperature from one year to the next.
- Weather Data is not yet available. We cannot perform normalization until weather data is available for the most current time period. Weather data is usually uploaded by the 15th of the month (e.g. weather data for November would be uploaded by about December 15).
- You've added/discontinued a type of energy. We need 12 full months of energy data for each fuel type you are using to calculate Weather Normalized metrics. So, if you recently added (or discontinued) a certain fuel type, then you will have to wait 12 months to get Weather Normalized Metrics back.
- You have too many outlier data points. One step in our normalization is to look at your data and remove outlier points (defined as differing from the mean by more than two standard deviations). These outliers are removed so that they do not distort your building’s normalization. After these outliers are removed you must have 5 calendar months of data left for us to use in normalization. If you do not, then we do not have enough data to attempt to discern a relationship between energy and temperature.
- This situation could be an indication that you’ve entered some of your bills in the wrong units (added an extra zero or left one off). You may want to double check your meter data if you believe this is a mistake.
* We use 24 (instead of 12) months of data is to increase the number of data points used to fit the relationship between energy and temperature and thereby increase the goodness of fit.
If you want to get into more details, here's our Technical Reference on Weather Normalization.