Determining Potential Energy Savings from Occupancy Data in EMS Lite and EMS Pro Databases

This article explains the steps necessary to determine potential energy savings per room using data from Dean Evans EMS Lite and Pro databases. (Note: EMS Enterprise has the ability to generate a room occupancy report, so you do not need complete steps 1-3 if you are using EMS Enterprise, although you can if you choose.)

The following steps are for advanced users.  Please contact your IT support for assistance.


Step 1: Copy the SQL script below (or use the attached file) and replace the underlined date/time sections with the time period you want to summarize. You can choose a time period of any length, but a year might be best for comparing data.


SELECT TOP (100) PERCENT dbo.tblBuilding.BuildingCode, dbo.tblBuilding.Description AS BldgDesc, dbo.tblRoom.Room,
dbo.tblRoom.Description AS RoomDesc, COUNT(dbo.tblBooking.ID) AS Bookings, SUM(DATEDIFF(mi, dbo.tblBooking.TimeBookingStart,
dbo.tblBooking.TimeBookingEnd) / 60) AS BookingHrs, SUM(DATEDIFF(mi, dbo.tblBooking.TimeEventStart, dbo.tblBooking.TimeEventEnd) / 60)
AS EventHrs, dbo.tblRoom.RoomSize
FROM dbo.tblBooking INNER JOIN
dbo.tblRoom ON dbo.tblBooking.RoomID = dbo.tblRoom.ID INNER JOIN
dbo.tblBuilding ON dbo.tblRoom.BuildingID = dbo.tblBuilding.ID INNER JOIN
dbo.tblStatus ON dbo.tblBooking.StatusID = dbo.tblStatus.ID
WHERE (dbo.tblBooking.TimeBookingStart BETWEEN CONVERT(DATETIME, '2008-08-01 00:00:00', 102) AND CONVERT(DATETIME, '2009-08-01 00:00:00', 102))
AND (dbo.tblStatus.StatusTypeID = - 14)
GROUP BY dbo.tblBuilding.BuildingCode, dbo.tblBooking.RoomID, dbo.tblRoom.Room, dbo.tblRoom.RoomSize, dbo.tblBuilding.Description,
ORDER BY dbo.tblBuilding.BuildingCode, dbo.tblRoom.Room


Step 2: In SQL Server Management Studio, run the script with your EMS database selected.  Results will show up in the bottom pane.




Step 3: Select all of the results and right-click to save as a CSV file.  This file can be opened in Microsoft Excel for further analysis and formatting.


Step 4: Open your CSV file in Microsoft Excel. Add a column called Equipment Hours. Determine or estimate your equipment runtime for each room for the same period of time and enter it in the appropriate cell in this new column. 


Fill out the Equipment Hours column for each room. For example, if before implementing Events2HVAC you are running a room 10 hours per day, you would multiply 10 by the number of active days the building ran during the specified time period to get the equipment hours (10 hours/day x 7 days/wk x 52 wks/yr = 3640 hours/yr). Now you have the hours each room was used (Booking Hours) and the total hours the equipment ran (Equipment Hours). To determine your potential runtime savings if you implemented Events2HVAC, you just need to subtract the booking hours from the equipment hours.

Step 5: Create another new column to the right of the Equipment Hours column. This one will be called Runtime Savings. Setup an Excel equation to subtract the Booking Hours from the Equipment Hours in each row and put the difference in the Runtime Savings column. (See Runtime Savings column in previous screenshot.)

Your runtime savings for each room is the number of hours of energy that you can save after implmenting Events2HVAC. If you know the cost of running each room for one hour, you can now determine the potential dollar savings by multiplying the cost by the runtime savings.

You can also calculate % occupancy by using the formula 100 x (booking hrs) / (equipment hours). 

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