Degree days correction

The consumption of natural gas or other sources of heat for heating depends on the weather. The colder it is, the more heat is required. To see whether the increase in energy consumption is due to the weather you can correct gas consumption by degree days. Degree days correction has no effect on the environmental impact and CO₂-emissions (because you really consume so much gas / wood chips / district heating), but there are several indicators that calculate the degree day corrected consumption.

The number of degree days is the number of degrees the average daily temperature of the day is below 18.0°C. By adding these degree days you will get the number of degree days of a month or a year.

When looking for data on degree days, you will encounter unweighted and weighted degree days. Weighted degree days are adjusted for the influence of the sun on the perception of the temperature in a building. In spring and summer, the contribution of solar heat through windows is higher than in winter; at the same outside temperature you get more ‘additional heating’ from solar radiation. As a result, you will burn more gas on a 10°C winter day than on a 10°C spring day to get the same level of comfort. In general, choose for weighted degree day.But if you have few windows on the south, for example, unweighted degree days may be better. You can determine this yourself the best.

Instruction for entering data

• Find the degree days for your location. For example at:
  • www.kwa.nl
  • Mindergas.nl/degree_days/calculator.
• In the envirometer go to “enter data> fuels> fine tuning” and check mark:
  • Degree days this year
  • Average degree days
• Go back to “enter data” and
  • Choose “all years> fuels> degree days this year”
  • Enter the degree days per year. The higher the number, the colder that year.
  • Switch to average degree days and enter for each year the same number (the average of the past ten years).

Instruction visualizing key figures

• Go to indicators> finetuning> fuels (in the right margin)
• Check mark one or more of the following items:
  • Heating (degreeday corrected)
  • Heating energy per m³ (degree day corrected)
  • Heating energy per m² (degree day corrected)
  • Heating energy per fte (degree day corrected)
  • Heating energy per production unit (degree day corrected)
• Go back to indicators and if all goes well, you’ll see the corrected gas consumption. Those numbers show some a bit more honest if you really saved fuel or that it only was related to it being a warm year.