Living Space Area: What Are the Criteria to Calculate It

Since 2016, Luxembourg has defined standardized criteria for calculating the living space area of a dwelling. This is very useful for buyers as well as sellers and real estate experts, as these indications allow people to know the actual surface area of an apartment or house. Here is how to calculate a living space area:

An Impartial Calculation of The Living Space Area of a Property

On March 15, 2016, the ILNAS (Luxembourg Institute of Standardisation, Accreditation, Safety and Quality of Products and Services) published a norm regarding the living space area of a dwelling. This norm only applies to residential real estate and allows to calculate accurately the surface of a property, in square meters.

This norm has many advantages:

  • The methodology is accessible to everyone.
  • The living space area provides a common language between all real estate players (professionals and individuals, buyers and sellers, landlords and tenants, etc.).
  • It helps to compare more easily different properties according to objective criteria: the living space area and, by extension, the price per square meter.

How to Calculate the Living Space Area?

The ILNAS norm 101: 2016 provides a detailed calculation for the living space area, which is available online. Note that it allows for 5% margin of error - positive or negative - relative to the actual living space area.

Rooms Included in the Calculation

In practice, the living space only refers to the surface intra-muros (abbreviated as "SIM"). According to the definition, the calculation of SIM includes all visible, accessible and measurable interior surfaces, which the people living in the property are directly or indirectly using.

This therefore includes:

  • The different rooms: living rooms, kitchens, bedrooms, dining rooms… but also dressing rooms and cupboards.
  • The bathrooms and toilets.
  • The circulation areas: stairs, hallways, etc.

In addition, measurements are made at the floor level, just above the skirting boards. In order to calculate the living space area of a property, you need to add all the surface area listed above.

What is Excluded From the Calculation

On the contrary, many elements are excluded from the calculation of the living space area. These are called "accessory" surfaces, which are not intended for living.

These include:

  • Walls, partitions, window frames/doors and other building elements.
  • Common areas (in a building or residence).
  • Technical premises, garages and cellars.
  • Places with less than two meters ceiling height. If you have a vertical cadastre, you can easily identify these areas with insufficient height. This is called "cadastral surface area".
  • Attics and mezzanine floors that cannot be used or have not been converted. This is the case if there is no flooring, if the access is too difficult, if the framework is cumbersome or if the ceiling height is lower than two meters.
  • Balconies, terraces, loggias and unheated veranda.

In order to get a reliable calculation of the living space area of a dwelling, it would be better to contact a real estate expert.