How Mestro handles degree days and makes calculations based on them
In the portal, you as a customer can use either Degreedays or SMHI to retrieve degreedays. Through SMHI, you can also download the energy index. You can read more about these below. Degree days are used for climate correction of heat and cold.
What is Climate Correction of heat and cold?
Climate correction is used to more fairly assess how efficiently a building is heated by its heating system, as the energy consumption to heat a building strongly correlates to the outdoor temperature.
To calculate degree days for a day, you check the deviation of the daily average temperature from the base temperature. The base temperature is the outdoor temperature as no energy needs to be supplied to the building to maintain a pleasant indoor climate. A month's degree days are calculated by summing up the days' degree day deviations and to get the normal year, the average of all the month's degree days is taken over a longer period.
Climate correction and degree days in the Mestro portal
Mestro reports the degree days for the locality if you activate climate correction in report settings and record the usage report for a single property or several properties located in the same locality. It is therefore not possible to see degree days for an entire portfolio if the properties are located in different cities.
You can advantageously use the climate correction when you compare properties heating and cooling use in the ranking report. By taking the outside temperature into account, you get a measure of how well the property actually stands against itself and other properties compared to the previous period. This is visualized in the example below. With climate-corrected heat, it turns out that two municipalities performed better and reduced energy use for the three selected months compared to the same period the year before.
Note. You cannot toggle the climate correction in the usage analysis if you want to look at hourly data because the degree days are adjusted monthly.
Baseload months
Usually the heat is used both for heating the building itself but also for heating water. It is only the heating portion of the total heat supply that you want to climate correct. Under the edit tab there is a section called calculations/hot water share. There you can make settings that determine the proportion of hot water in the heat energy, i.e. the amount of energy that should not be climate corrected.
There are three main ways to adjust the amount of heat used to heat water.
1. You can choose to deduct the amount of heating used during the year by selecting the base load months calculation type. You can freely choose which months you want to base this amount on. The system uses the average usage of the months selected.
2. The second type of calculation is to choose a certain percentage of the rolling 12 month heating and then subtract the amount divided by 12. This is a rolling calculation for each month.
3. The third option is to enter a constant value which is then deducted on a monthly basis from the correction.
Mestro's handling of degree days
This is how Mestro corrects the climate (cold and heat):
- For properties with heat meters, zip code and country entered in Mestro Portal, degree days will automatically be retrieved from Degreedays. It is also possible to collect degree days from SMHI.
- Normal years for Degreedays are always calculated in the same way (average for a month between 2005 and 2012). See below for calculations for SMHI.
- Base temperature for all properties in Mestro is 17°C.
Mestro calculates a factor by dividing the current year's degree days by the normal year's degree days. The real consumption is then divided by this factor, which means that larger deviations in temperatures will result in climate-corrected consumption figures. The normal year-corrected energy deviates at most by +50%/-40% from the measured energy.
Activation of degree days for heating takes place automatically via Degreedays, but when it comes to degree days for cold eaters, you need to contact your Customer Success Manager or Mestro Support. This also applies if you wish to use SMHI.
Normal year correction from SMHI
Degree days can also be collected from SMHI if desired, it needs to be ordered directly from SMHI.
Degree days or Energy Index
SMHI offers climate correction factors for both the Energy Index and degree days from 310 locations in Sweden. The degree day factor takes outdoor temperature into account. The energy index takes into account more parameters than just temperature, such as wind, precipitation and solar radiation. Mestro can today read the Energy Index for the Standard Type House 105.
SMHI calculates a recommended correction factor for both the Energy Index and normal year correction, which are also the factors by which we correct energy use in Mestro Portal.
SMHI has different normal year periods to choose from; 1971-2000, 1981-2010, 1991-2020. Since the release in January 2023, Mestro can handle different normal years in parallel. This means that you can set which normal year to correct for in the report settings. See image below how to change between them in report settings:
Do not hesitate to contact your Customer Success Manager or support@mestro.com if you want to learn more about the degree day correction, Degreedays or SMHI.
If you want to change your place of graduation
Which location is used for retrieving degree days is shown at the top of the edit tab if you are standing on the property in the structure.
If you want to change location, it is usually possible, contact the support which location you want to change to!
Places we can use need to have data from at least 2005, this can be seen on me Search for the location you wish to use and hover over it, then it will be clear from when the location has data.
One last thing just…
We are a company that is in constant development and therefore welcome both suggestions and feedback from you. Do you think there is something missing? Is there a feature that could work better? Don't hesitate to get in touch with your Customer Success Manager or send us your thoughts at support@mestro.com. We would really appreciate your opinions on how we can make Mestro even more useful for you!