Who owns your
building’s data?

The question always comes up too late: the day you change operator. And the legal answer is not the one you expect.

The wrong question

Under Swiss law, nobody owns a building's data. That is not a turn of phrase: it is the state of the law, and it is written in black and white in an official report. Mandated by the Federal Council, the Swiss Federal Institute of Intellectual Property published its report “Access to non-personal data in the private sector” in March 2021. Its key sentence: “The Swiss legal order does not recognise ownership of non-personal data as such.” Nor is there any database right, unlike in the European Union. And the report explicitly recommends not creating one: rather than legislate, it offers model contracts, which the Institute has published ever since.

The same report adds a qualification that changes everything for a building owner. Trade secrecy, unfair competition law and a handful of criminal provisions protect whoever holds the data to the point of giving them, in the report's words, “a legal position very close to a property right”.

In plain terms: there is no owner, but there is a holder, and the holder is almost in an owner's position. If that is not you, it is someone else.

So the question “who owns my data?” has no answer. The useful question is twofold. Who physically holds it today? And what does my contract entitle me to demand tomorrow? Because a contract only binds those who signed it.

A building does not produce one kind of data, it produces four

That is where the confusion starts. We speak of “the data” as a single block, when it does not live in the same place and is not lost in the same way.

Operating measurements — temperatures, flow rates, meters, statuses, faults — originate in the controller, which keeps only a few days of them, and accumulate in the supervision database. That is the most visible layer, and the easiest to recover.

Project files are the critical layer: the controller program and its source, the ETS project of a KNX installation, the supervision graphics, the points list and its EDE export, the control parameters. Without them you can still read the installation; you can no longer change it.

Configuration and access data comes next: administrator accounts, passwords, licences, certificates, remote access. It weighs nothing and decides everything.

Finally, personal data: badges, room-level presence detection, cameras, consumption traced back to a workstation. That one is not a matter of contract but of the Federal Act on Data Protection, revised and in force since 1 September 2023 — with a stated purpose, a retention period and a designated controller. A building owner who does not know that the BMS logs every badge swipe at the plant room door will find out at the worst possible moment.

The three ways to lose control

None of them looks like theft. All of them pass for technical detail.

The format, first. Trend data you can export as CSV is yours. Trend data that only comes out through the manufacturer's tool, in a binary file only that tool can read, stays with them even when it is stored on your premises.

The hosting, next. Many recent installations send their data up to the manufacturer's cloud. That is convenient, and not in itself a problem — until the service contract ends. What happens to ten years of history? Is it returned, in what format, at what price, within what deadline? If the contract is silent, the answer will be the supplier's.

The account, last, and the most common of all. The supervision administrator credentials belong to the integrator, not to the building owner. While the relationship is good, nobody notices. The day it ends, the owner discovers they cannot create a user in their own installation.

Project files, the real friction point

This is where the discussion gets serious, because two rights coexist and are routinely confused.

A controller program, supervision graphics, a schematic are their author's work, and that author keeps the copyright. The SIA says as much in its position paper on the subject: transfer of rights is never presumed, the client acquires a right of use for the agreed purpose, and a broader assignment is negotiated and paid for. This is not an abusive position; it is the common rule for every design professional in construction.

But copyright and possession of the file are two different things. Nothing prevents agreeing, at signature, that the program source and the ETS project are handed to the building owner at acceptance, with a right to use and modify them for operating, maintaining and extending the building — including through a third party. The author remains the author; the owner is no longer locked in.

What costs money is never the clause. It is writing it afterwards.

The European detour that concerns you anyway

The European Data Act has applied since 12 September 2025, and connected products placed on the EU market from 12 September 2026 must be designed so that the user can access the data they generate directly.

Switzerland is not bound by that regulation. But most manufacturers of controllers, room units and platforms installed in our buildings also sell into the Union, and will have to comply there. A building owner in Valais can perfectly well require by contract what European law imposes 300 kilometres away: access to their usage data, free of charge, in a readable format, with the option of passing it to the service provider of their choice. The function will be in the product either way.

The six clauses to write before signing

1. Operating data can be exported at any time, without the supplier's involvement, in an open and documented format (CSV or equivalent), timestamp and point reference included.
2. The controller program source, the ETS project, the supervision graphics and the EDE export of the points list are handed to the building owner at acceptance, on media they keep.
3. A right to use and modify those files for operating, maintaining and extending the building, including through a third-party contractor.
4. Administrator accounts for the supervision and the equipment are in the building owner's name. The integrator receives a named, revocable account.
5. Where data is hosted externally, the contract sets out the return of the complete history at the end of the relationship: format, deadline, cost, and deletion at the supplier.
6. Personal data processing is listed with its purpose and retention period; anything not needed to operate the building is not logged.

These six clauses do not have to be invented from scratch: since 2024 the Swiss Federal Institute of Intellectual Property has published a practical guide and three model contracts for sharing technical data — precisely because the legislator declined to create a right in data and referred the question to contract.