The location contains all data about the surroundings of the entire project, such as location and climate.



This input field determines the so-called environmental factor. This environmental factor, in turn, affects the values ​​to be used for infiltration. There are three options for the location:

1. Flat open area
2. Woods, accidented area
3. City centre

Ground reflection

Ground reflection is the factor of light reflection on the ground relative to the incident light on the ground. The material of the ground, such as dry asphalt or water, directly influences this.

Default: 0.20

For more values, see

Climate Data

Heat loss- Outside design temperature

Deze ontwerpbuitentemperatuur geeft de vastgelegde buitentemperatuur voor de winter aan, bedoeld voor de warmteverliesberekening. De standaard buitentemperatuur is -10°C. De standaard buitentemperatuur wordt gecorrigeerd aan de hand van de berekende tijdconstante binnen het project. Dit kan met maximaal 4K, zodat een buitentemperatuur kan variëren tussen -10°C en -6°C.

Er kan naast de standaard buitentemperatuur volgens de ISSO publicaties 51, 53 en 57 ook worden gekozen voor een afwijkende buitentemperatuur. Voor de Nederlandse situaties is dit echter niet aan te bevelen.

This outdoor design temperature specifies the recorded outdoor temperature for winter, used for heat loss calculations. The standard outdoor temperature is -10°C. The standard outdoor temperature is adjusted based on the calculated time constant within the project. This adjustment can be up to 4K, allowing the outdoor temperature to vary between -10°C and -6°C.

In addition to the standard outdoor temperature according to ISSO publications 51, 53, and 57, an alternative outdoor temperature can also be chosen. However, this is not recommended for Dutch situations.



Cooling need

Outdoor design temperature

This design temperature indicates the recorded outdoor temperature for summer, intended for cooling load calculations. The selection list consists of the following reference years:

  • NEN 5067 1985;
  • NEN 5060 ref TO1 zeer streng;
  • NEN 5060 ref TO2 streng (default);
  • NEN 5060 ref TO5 gematigd

Absolute humidity

This is the maximum absolute humidity of the outdoor air in the vicinity of the project, used for calculating the latent cooling load caused by infiltration.

  • Default: 10,00 g/kg



 ISSO Publicatie 8 (1985), hoofdstuk 14

Calculation of the cooling load due to infiltration of outdoor air.


Building simulation

Climate file

Here, the climate file is specified that must be used for calculations. In the climate file, you choose from the installed climate files. The selection list is automatically generated based on the contents of the folder defined under Climate Files. This allows you to add additional climate files, for example, for different geographic locations and calendar data.

The choices are:

  • De Bilt 1964-1965 is included by default;
  • Dry cold climate is a climate file for testing the building simulation module and is included by default;
  • NEN5060 reference years (energie, TO1 zeer streng, TO2 streng, TO5 gematigd) are included by default (versions 2008 and 2018).
  • Import climate files from around the world using the climate wizard.
When the NEN5060 climate file is selected, a composite climate file is used. These climate data are based on the climatological data from the period 1986 to 2005 from the meteorological station De Bilt.

The year 1906 is chosen as a fictional year in Vabi Elements because the composite year does not have a specific year. This year was chosen because it starts on a Monday. Therefore, the data from 1986-2005 are used when NEN5060 ref is selected. You can also choose NEN5060 ref:2018 for more recent reference years.

Start date/ End date

Based on the selected climate file, you then define the start date and end date of the period you wish to use.

Amount of days

The number of days is calculated based on the start date and end date.


NEN 5060:2008 nl

Hygrothermal Properties of Buildings – Reference Climate Data

NEN-EN-ISO 15927-5:2004/A1:2011 en

Data for the design calculation of heat capacity for space heating


Building simulation daily outputs

Warmest and coldest day in reporting period

This displays a daily report of the warmest and coldest days of the year in the Building Simulation output. Note: This only works when no more than 10 spaces are calculated.

Select day in report

This displays a daily report of the days you have specified in the Building Simulation output. Note: This only works when no more than 10 rooms are calculated.

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