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This documentation relates to EnergyCAP version 3.6.
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Calendarization more accurately allocates utility bill usage and cost data for reporting purposes by dividing the data into day-size chunks and allocating them to the appropriate calendar month using weather adjustments. Without daily meter readings the splitting can’t be exact, but it is reasonably accurate.

Most utility bills have start and end dates that do not correspond to an exact calendar month:

Exact calendar month:

Start date: 9/1/2011End Date:  10/1/2011
Start date: 10/1/2011End Date: 11/1/2011

Typical utility bill:

Start date:  9/12/2011End date:  10/14/2011
Start date: 10/14/2011End date:  11/13/2011

Why calendarize?  Calendarization provides better month-to-month and year-to-year comparisons for reporting purposes by more accurately allocating monthly usage from bi-monthly and quarterly bills, estimated bills, and bills with variable billing periods (28 days one month, 34 days the next).  The calendarized data is therefore more representative of actual monthly energy use when used in fiscal reporting, budgeting, auditing, accruals and energy performance evaluation.

In EnergyCAP, two methods of calendarization are used.

Option 1: Simple average daily use and cost allocation

When a meter is not weather sensitive, the bill is simply prorated into each month based on the number of billing period days.  A bill from 9/12 to 10/14 has 32 days (the first day counts, the last day doesn’t because the next bill begins on 10/14).  There are 19 days in September, so 19/32 of the usage and cost is allocated to September and 13/32 to October.

Option 2: Weather (degree day) allocation

When a meter is weather sensitive, the simple method described above is inadequate and provides less reliable results.  A much more sophisticated method is used to prorate the weather sensitive portion of the energy bill based on the number of degree days in the appropriate billing period in each month, and to prorate the remaining non-weather sensitive portion based on the number of days.  See the Use vs. Weather topic for more details.

Annual Totals

Note that calendarizing does not appreciably affect annual totals. Since the calendarization process merely moves usage and cost data to the most appropriate calendar month for reporting and analysis purposes, the annual usage and cost totals should be almost identical to the actual data (the data shown on a billing period basis).  There may be slight differences due to year-end roll-over, but that is typically less than 1%.

In EnergyCAP, calendarized data is displayed in two places:  calendarized reports and the Calendarized Data tab.

Additional Information:

  • The weather regression calculations used by Calendarization and Normalization do not exclude statistical outliers.  Calendarization and Normalization data is not intended to be used for IPMVP approved cost avoidance purposes which would need the more precise weather regression result that is produced when outliers are excluded. 


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