Understanding Living, Useful, and Weighted Area in Swiss Real Estate

Learn how living area, usable area, and weighted area are calculated in Swiss real estate listings. Understand the differences between SIA standards and net living area and weighted surface.

Introduction: Why Are There So Many Different Area Measurements? 

When browsing property listings in Switzerland, you’ll quickly notice that area specifications aren’t always presented the same way. That’s because there is no single national standard for measuring living space. Instead, different methods are used depending on the region and the context of the sale.

Below, we explain the most common terms you’ll encounter, so you can better interpret the figures shown in real estate ads.

What Counts as Living Area?

The net living area (as defined by the Federal Housing Office, WBS/SEL) includes all year-round habitable rooms that can be heated and used. Spaces like bedrooms, living rooms, and kitchens fall under this category. Storage rooms and pantries also count—provided they meet the minimum height requirement of 1.5 meters.

Excluded from the net living area are rooms and spaces that are not meant for continuous residential use. Examples include unheated basements, garages, attics, balconies, and terraces. Importantly, wall cross-sections are not included in the net calculation but are part of the gross living area.

The Concept of Usable Area

The usable area is defined in the Swiss SIA Standard 416 and is divided into two parts:

• Main usable area: All rooms within the apartment that directly serve residential purposes. Even spaces occupied by built-in furniture, like wardrobes or kitchen appliances, are included. Outdoor spaces, basements, attics, and garages are not.
• Ancillary usable area: Supporting rooms such as laundry facilities, storage rooms, refuse rooms, attics, and shelters. These aren’t living rooms but still add functional value to a property.

Weighted Area in French-Speaking Switzerland

In the French-speaking part of the country, you’ll often come across the term surface pondérée (weighted area). This system is mainly used when selling condominium properties.

It combines the standard living area with outdoor and additional spaces, applying specific weighting factors:

• Balconies: 50%
• Terraces: 30%
• Gardens: 10%

This method provides a more comprehensive picture of the usable and enjoyable space in a property, especially for apartments with generous outdoor areas.

Why This Matters for Sellers and Buyers

Understanding these distinctions is crucial, whether you’re comparing properties or preparing to sell your own. Misinterpretations can lead to disappointment or inflated expectations. When reviewing a listing, always ask which measurement standard has been applied.

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