Here are the frequently asked questions below. Most likely, the answers can quickly help you further.


I want to import a 2D CAD file, but it's not working properly. Why is this happening?

There are several requirements that the CAD drawing must meet. If the drawing is not done correctly, many red areas and points may appear, which are difficult to repair afterward. Pay attention to the following points, for example:

  • The floor plan must be drawn with single lines. When two lines are drawn over each other, this can cause problems.
  • Ensure that each floor plan has its own layer.
  • Make sure that all lines have a height (z-value) of 0.
  • If there are multiple drawing layers, ensure that the lines are precisely aligned. This will prevent import problems.
When updating, the central library will not be lost. However, it is recommended to back up the central library before removing the previous version of Vabi Elements (step 2) during an update.

Download the document with the 10 key points for importing a 2D CAD Drawing in Vabi Elements.

How can I adjust the height of a floor afterward?

This is possible by dragging everything above this floor upwards, as demonstrated in this video:

Building Simulation

Why does it show the climate year as 1906 when I select the climate file for NEN5060?

When you select the climate file for NEN 5060, Vabi Elements uses a composite climate file. This composite file is based on meteorological data from the period 1986 to 2005 from the De Bilt weather station.

The year 1906 is chosen as a fictional year in Vabi Elements because the composite year does not have a specific year associated with it. 1906 was chosen because it starts on a Monday. Therefore, the calculations are actually based on the climatic data from 1986-2005.

Why do I have so many PMV undershoot hours, even though it doesn't get colder than 20°C?

The PMV requirement according to the international standard NEN-EN-ISO 7730 provides a theoretical assessment of the percentage of people dissatisfied (PPD) with comfort in the space (see Figure 1). A negative PMV indicates that people feel too cold, while a positive PMV indicates that people feel too warm.

Even if it does not get colder than 20°C, people may still perceive it as cold, resulting in undershooting hours.

This can occur due to a too low CLO and MET value, which can be adjusted in the Internal Heat Production by Persons. In addition, large windows can cause cold radiation, and humidity also affects how comfortable the indoor climate is perceived. It is recommended to verify your input based on these factors.

Check out the Whitepaper on testing comfort requirements for more information.
I get the message Program stops - Subroutine pschrom.f Dry Bulb Temperature in K negative, what does this mean?

This message is related to a high moisture content in a space. This can be caused by insufficient or no ventilation with treated air, high occupant load, low room temperature, or significant infiltration (moist outdoor air). We recommend verifying the input data in these cases. A first action could be to remove the heat recovery unit (WTW) from the air handling system and check if the calculation proceeds. If a WTW is used, there is a check on the return condition.

Next, in the output, you can search for spaces where high relative humidity (RH) values occur and when they occur. In the daily output graph of the relevant spaces, the likely cause can probably be found. For example, there may be high occupant load but no ventilation.

Another possible cause is a U-value of 6 W/m²K or higher, or the use of more than one cavity in the construction. Also, incorporating metal into the construction can trigger this message.

What happens if I do not calculate a space?

When a space is not calculated, it is considered identical to the adjacent space that is calculated.

However, it is recommended to calculate all surrounding spaces for a more accurate result.

My calculation takes a long time. What can I do to shorten the calculation time?

A long calculation time can have various causes. It’s worth paying attention to the messages during calculation.

One source of increased calculation time can be the geometry. Geometry with many orientations leads to longer calculation times. This can occur when trying to model a curved facade using many small surfaces, each with its own orientation. Even small differences in orientation angles, such as 89.99°, 90.00°, and 90.01°, can contribute to this. Cleaning up unnecessary lines is also beneficial: the more surfaces there are, the longer the calculation time.

Installation-related aspects can also increase calculation time, such as the presence of underfloor heating, floor cooling, or concrete core activation. These factors significantly increase the required calculation time. Using unlimited capacities for heat emission devices or generators also results in many iterations. In these cases, specifying capacities can be helpful.

Of course, large projects with many spaces that are all calculated contribute to long calculation times. It may help to initially calculate only a limited number of rooms for the conceptual choice phase.

Heat loss

My heat loss calculation using ISSO 51/53/57 from 2012 differs from the new heat loss standard from 2017. Where do these differences come from?

There have been many changes in the new standard compared to the old one, including a correction to the design outdoor temperature based on the building’s time constant.

You can find an overview of the changes here.

How do I enter an unheated room?

To calculate the balance temperature for an unheated space, in the room requirements template, the temperature field should not be filled in; instead, it should be marked as “standard.” Additionally, in the heat delivery template, there should be no heat emission device present. No heat exchange is calculated between two unheated spaces. If a heating coil is present in the air handling unit, then air heating is calculated for living spaces and areas. In

What happens if you don't include a room in the calculations?

If you do not include a room in your heat loss calculation, that room will be assigned the room temperature specified in the room requirements template associated with the room. If the adjacent room is an unheated space, then the calculated balance temperature for the unheated space will be used in the calculation.

The temperatures of the rooms in an adjacent building are different than I would expect given the U-value I have entered for my constructions (ISSO 51 H4.5). How is this possible?

When determining the temperature of adjacent buildings, the values entered under “Building Properties” are considered. Clicking on the pencil icon allows you to enter the average R-value.

The number of homes is determined based on the geometry. These homes must then be entered as heated zones.

I use heat recovery in my air handling unit (AHU), but I still have a very high ventilation loss. How is this possible?

This could be because in the air handling unit, there was no selection for preheating the outdoor air for frost protection.

If no/unknown frost protection is chosen or if it’s managed by throttling/backturning/temporary imbalance, the design outdoor air temperature will be used in the calculations, resulting in significant ventilation losses.

When I add up the heating capacities of my rooms, I get a different value than what is indicated for the total building heat loss. Where does this difference between connected load and total transmission loss come from?

At the room level, you determine the emission device to be installed and what it should be able to deliver.

At the building level, you determine what the generator for the entire building must be able to supply.

The differences are as follows:

Per room:

  • Needed to determine local emission devices and local installations
  • No heat emitted to the outside by floor and wall heating

System B/D

  • Maximum infiltration loss
  • Air enters the room already heated
  • Maximum ventilation

Building total

  • Needed for determining central installations, such as central heating (CV), heat-cold storage (WKO), air handling units (LBK), etc.
  • Heat emitted to the outside by floor and wall heating

System B/D

  • Infiltration loss × fraction z
  • Preheating of air (centrally preheated)
  • Ventilation according to VLA methodology

Cooling load

Why are there no results and/or is the maximum cooling load 0W?

Check in the “Emission System Templates” if the checkbox “Cooling present” is checked in the “Emission devices” section. When this checkbox is checked, the rooms linked to this emission template will be included in the cooling load calculation.

Why don't the sun blinds switch on?
  1. Check in the Building Control Templates if the “Sun shading control level” is set to “Regulated”.
  2. Verify if this Building Control Template is linked to the building in Building Properties.
  3. Check if sun shading is present in the applied windows in Construction Tools.
Yes, you can enter an outside temperature yourself.

Outdoor conditions cannot be entered. The cooling load standard refers to the climate years according to NEN5060, which are based on the Dutch climate. Nothing else can be used. However, in building simulation, this can be done!

But in cooling load, you can trick the outdoor temperature without losing solar radiation: Outdoor condition in cooling load


What are the points of attention when setting up an EPG project?

Check out the article with all the key points for EPC to ensure your calculation is successful.


Does Vabi also provide training with Vabi Elements?

Yes, Vabi provides introductory training sessions for a flying start “Navigating the platform“. They also offer trainings that combine methodology and software, such as “Building simulation: comfort and energy” or “Heat loss & Cooling load“. Additionally, customized on-site training sessions are available.

In addition to these trainings, we also have an Online Academy where you can learn the basics of Elements yourself.


How long is the duration of my subscription (license agreement)?

License agreements are always entered for the remainder of the current calendar year and the following calendar year, so a maximum of 2 years. After this period, subscriptions are automatically renewed. Invoicing occurs prior to each calendar year.

Which services are included in my subscription?

As a customer of Vabi, you always benefit from our assurances at no additional cost:

  1. Methodology updates to ensure you always work in compliance with the latest laws and regulations.
  2. Feature updates, without needing to make new purchases, to make your work more enjoyable and easier.
  3. An expert is always available to provide you with personal advice using Vabi Elements.
  4. Includes free update training at the Vabi Academy in Delft, and you can utilize our convenient Online Academy.
Are there different types of licenses?

You always start by ordering a basic license per module, which you can use on a maximum of 2 PCs within your company. For additional PCs, you pay a reduced rate with an extra PC license per module.

How many PCs can I use one license on?

Every company is required to purchase a base license. With the base license, you can use the software on up to two PCs within the company. From the third PC onward, you will need additional workstation licenses.

Example: If you want to use Vabi Elements Heat Loss on 3 PCs, you would need one base license (for the first two PCs) and one additional workstation license.

How can I cancel my license?

We hate to see you go, but you can cancel your license by sending an email to sales@vabi.nl. It’s good to know that license agreements run until the end of the calendar year.

Installation and activation

I want to install Vabi Elements on another computer, how do I do this?

To free up a workstation, you need to uninstall Vabi Elements. If you’re having trouble uninstalling Elements, please call our service desk. Since July 2018, the licensing system has been changed to one license per Windows account. This allows one user to work with different hardware. However, Vabi Elements can only be used on one workstation at a time.

How do I install Vabi Elements?

Follow these steps to install Vabi Elements:

  1. Download Vabi Elements and open the downloaded setup file.
  2. Select your language and click OK. This language setting is for the installer and does not affect the language settings within Vabi Elements itself. Click Next.
  3. Carefully read the license agreement and accept the terms.
  4. Choose the installation folder where you want to install Vabi Elements and click Install. By default, this will be %programfiles%\Vabi\Elements.
  5. The program will now be installed. During installation, the setup will attempt to connect to the internet to find the latest version of DirectX. Depending on your internet connection, this may take some time. Optionally, select the components you wish to install and click Next.
  6. Optionally, give the installation a different name that you can find in the list of Windows software. Click Next.
  7. Choose where you want additional shortcuts to Vabi Elements. Click Next.
  8. Click Install. The program will now be installed.
  9. You can choose to start Vabi Elements immediately. Click Finish to complete the installation.

During an update, the central library will not be lost. However, it is advised to back up the central library before removing the previous version of Vabi Elements (step 2).

How do I activate modules in Vabi Elements?
  • Go to Extras – Activation Screen
  • Enter your license details

The customer number is a six-digit code from your company (enter without CN and possibly with an extra 0 at the end).

Your technical administrator has created user accounts. Enter the email address associated with your user account. You can also use this to log into the client portal.

Enter your password. Forgot it? Go to user.vabi.nl and request a new password.

  • Select the modules you want to activate and click Activate/update.
  • The modules are now activated.

You need to be connected to the internet to activate Vabi Elements.

What are the recommended system requirements for Vabi Elements?

Below is the table showing the minimum and recommended system requirements. To work effectively with Vabi Elements, it is recommended to choose specifications from Medium or High performance.

Minimum Medium performance High performance
Windows version Windows 8 Windows 10 Windows 10
Storage Type HDD SSD SSD
Processor Intel core i3 (dual core) Intel core i5 (quad core or higher) Intel core i7
RAM 4 GB 8 GB 16 GB
Graphics card Standard onboard processor graphics Standard onboard processor graphics 2GB or 4GB graphics card
Software .NET framework version 4.7.2 .NET framework version 4.7.2 .NET framework version 4.7.2
DirectX 9 or later (recommended) of OpenGL 3.0 DirectX 9 DirectX 9
Is the software also available in English?

Certainly, in the top menu bar, there is an option “extra”. If you choose “voorkeuren” here, then under “Algemeen”, you can change the “Taal” from Dutch to English

Next, in the same screen under “Bestandlocaties”, you can replace VabiLibrary-nl.vl with VabiLibrary-en.vp for the Central library.

When the language is set to English, pressing the F1 key from within the software will directly lead to the original online help in English.

You can find the most recent English manual in PDF format here: English manual.

Is the software available in the English language?

Yes, in the top menu you choose the option “extra” and at “voorkeuren” you choose “Algemeen”. Here you can set at “Taal” the language from “Nederlands” to “Engels.

It is also neccesary to go to “Bestandlocaties” and set the library to English: instad of VabiLibrary-nl.vl you choose VabiLibrary-en.vp.

If the language is set to English the [F1] button will open the former on-line-help in English.

The most recent English manual in pdf: English manual

Personal advice

If you’re still unsure, don’t hesitate to give us a call or send us an email for personalized advice. The Vabi Elements Support Desk is open on weekdays from 9 AM to 5 PM.

Mail to elements@vabi.nl
Call 015-2133501

Contact form

Afbeelding van Esther Krombeen, consultant bij Vabi
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