Compare energy consumption using degree-day adjustment

Degree-day adjustment makes it easier to compare energy consumption between periods with different weather conditions. In Evolo, this is used to compare energy performance over time and across buildings in a more equitable manner.

Written By Evolo Support

Last updated 17 days ago

What is a degree-day?

A degree day indicates how much the outdoor temperature deviates from a building’s set point over time. The set point is the temperature at which the building normally does not require heating or cooling to maintain the desired indoor temperature. In Norway, 17 °C is often used as the set point.

Example: If the outdoor temperature is 10 °C and the balance point is 17 °C, that results in 7 heating degrees for that day.

Why use degree-day correction?

Energy consumption is affected by the weather. A cold month will often result in higher consumption than a mild month, even if the building is used in the same way.

With degree-day correction, you can:

  • compare consumption between periods more fairly

  • track changes in energy performance over time

  • better compare buildings with different weather conditions

How does it work?

Degree-day adjustment adjusts the temperature-dependent portion of energy consumption based on the number of degree-days during the period.

A meter reads 10,000 kWh in a month with 300 degree days. If the same month the following year has 250 degree days, the corrected consumption can be calculated as follows: 10,000 × 250 / 300 = 8,333 kWh

How degree-day correction works in Evolo

In Evolo, you can enable degree-day correction in all comparison charts.

You can set:

  • a balance point for each meter

  • heating share, i.e., what portion of consumption is used for heating

This ensures that only the portion of consumption that is actually temperature-dependent is adjusted.

For individual meters

The correction is based on the period with the most valid meter readings within the selected date range.

When comparing buildings

Evolo the meter with the most valid readings is used as a reference for the other meters.

If temperature data is missing

Missing temperature data for an entire period results in a degree-day count of 1. In that case, no correction is made.

Data Basis

The calculations are based on the daily average temperature.

Important to note

Degree-day correction depends on reliable temperature data. Missing or inaccurate data can lead to misleading results.

Common challenges:

  • Missing temperature data creates gaps in the calculation

  • Inaccurate temperature measurements can result in incorrect corrected consumption

  • comparisons between buildings become less reliable when data quality varies

To achieve the best possible results, temperature data should be stable, consistent, and complete.

Degree-day correction provides a better basis for comparing energy consumption when weather conditions vary. The best results are achieved when the temperature data is complete and accurate.