Note: Measurement and Verification reports, drift charts, variance by source tables, and long-term trend graphs are available for meter data. Buildings and groups can see streamlined variance analysis tables comparing the most recently available period to the same period one year prior.
What is weather-normalized change in energy use?
Weather normalization isolates the changes in a building’s energy use that can be attributed to changes in the weather from changes attributed to other causes.
In most buildings, weather has an impact on how much energy is used. Imagine if September 2024 had above-average temperatures while September 2025 was below average. Comparing those two months directly would be apples to oranges. But by filtering out weather effects — by correcting for observed differences in temperature — you can isolate the other changes and focus on what’s actually happening inside the building.
Customizable drift charts
Comparing the change in energy use from one month to another is as simple as selecting one Analysis Period and one Baseline Period. The Baseline Period must come before the Analysis Period on the calendar.
The drift chart automatically updates to the date ranges you select. Move your cursor anywhere inside the chart area to see each interval reading’s Analysis Period demand and corresponding Baseline Period demand.
- Day of the week: Across the four weeks of the month, Gridium averages together all Monday load curves, all Tuesday load curves, and so on. This allows the drift chart to be summarized within one calendar week.
- Analysis period demand: This line is an average load curve for each day of the week during the four calendar weeks of the Analysis Period month.
- Decrease from baseline: The light blue shaded area shows when the Analysis Period demand is lower than the Baseline Period demand. Nice work!
- Increase from baseline: The light yellow shaded area shows when the Analysis Period demand is higher than the Baseline Period demand.
Variance by source table
The foundation of a Measurement and Verification report is the Variance by source table. This is where you can see Gridium’s calculations isolating the causes of changes in how your meter uses energy.
- Baseload use: Gridium splits your meter’s load curve into its component parts, including baseload use, and automatically updates as new data becomes available. This is the portion of energy use that occurs when the meter is not considered to be fully operating. The % change is relative to the Baseline Period’s baseload use, not the total change.
- Temperature response: This calculation combines two quantifiable factors: weather conditions and your building’s response to changes in the weather. It estimates the net effect of weather conditions on the meter’s energy use. The % change is relative to the Baseline Period’s weather-driven use, not the total change.
- Operational use: The variance between the Analysis Period and the Baseline Period is composed of three things: baseload, weather, and operations. Since Gridium can calculate the first two components, the remaining portion of the variance is attributed to operations. The % change is relative to the Baseline Period’s operational use, not the total change.
- Total: The total change reported here is for the calendar period selected, and therefore unlikely to tie exactly to a specific utility billing period. The kWh / 4 weeks figures for baseload, weather-driven, and operational use do add up on this line, but the % change is relative to the Baseline Period’s total change amount.
Isolate drivers in the long-term trend graph
While the drift chart isolates the change between two selected months, the long-term trend graph lets you explore your meter’s entire interval data history, with each interval reading split into its component parts: baseload, weather-driven, and operational use.
Helpful hint: Click each variance component on or off in the chart’s legend to isolate one or more lines on the graph. Changes in baseload use are particularly easy to spot when it’s the only line showing.
Total kW may equal zero when there are power outages or gaps in the meter’s underlying interval data. Weather-driven use measures the incremental energy used by the meter that can be attributed to changes in temperature; it is therefore always a non-negative number. Since operational use is the remaining value after baseload and weather-driven use are calculated, it can occasionally show a negative kW reading.