Ask ten property teams what makes a building smart and you will get ten answers, most of them a list of equipment. The more useful test is far less glamorous: can you read the building’s data, and can you take it with you when the contract with the integrator ends?
What actually decides the outcome
- The European smart readiness indicator is still voluntary, but the Commission has a report due in June 2026 and a delegated act due by 30 June 2027.
- Protocol choice is largely settled. BACnet is standardised as ISO 16484-5, KNX as ISO/IEC 14543-3.
- The unsolved layer is semantic: making a data point mean the same thing to two different applications.
- Data ownership is contractual, not technical. It is won or lost in the handover documents.
Regulation is turning a marketing word into a rating
The clearest signal that the category is maturing is that public authorities have started to score it. The recast Energy Performance of Buildings Directive, Directive (EU) 2024/1275, keeps the smart readiness indicator as an optional scheme that member states may test and implement as they choose. Its Article 15 also sets the schedule that turns it into something firmer: a Commission report on the national test phases due by 30 June 2026, and a delegated act by 30 June 2027 requiring the indicator to be applied to non-residential buildings above 290 kW of installed heating, cooling or combined ventilation capacity.
Two practical consequences follow for anyone planning a project now. A building specified in 2026 will very likely be rated under that scheme during its operating life, and the same directive has already extended the required functions of automation systems to include indoor environmental quality monitoring. Comfort and air quality are no longer soft benefits sold to tenants; they are becoming reportable outputs.
Interoperability: the layer that decides who is in charge
Communication between building systems is a solved problem at the transport level and an open one at the meaning level. BACnet, published as ANSI/ASHRAE Standard 135 and internationally as ISO 16484-5, dominates plant and supervisory communication. KNX, standardised as ISO/IEC 14543-3, is common at room level for lighting, blinds and comfort control. Modbus persists at the field device edge because it is simple and ubiquitous. Gateways translate between them.
What none of those protocols do is tell an analytics application what a data point represents. A value arriving from a controller may be a supply air temperature, a setpoint or a sensor in a plant room, and the difference is usually carried in a naming convention invented by whoever commissioned the site. That is the gap the semantic modelling work is meant to close, through tagging and modelling initiatives such as Project Haystack and Brick and through ASHRAE’s proposed Standard 223P, still at proposal stage with publication expected during ASHRAE’s 2026 fiscal year. Until it lands, expect to pay someone to map points by hand on every retrofit.
What to secure at handover
The moment that determines whether a smart building stays smart is the handover, not the design review. These five items cost nothing to request during procurement and are expensive to recover afterwards.
| What to ask for | Why it matters later |
|---|---|
| The full points list with its naming convention | Without it, every future analytics or reporting project starts by re-discovering the building |
| Administrator credentials, in writing | Owners routinely discover they hold operator rights only, and cannot change a schedule without a call-out |
| Documented open protocol interfaces on each subsystem | Decides whether the next contractor can integrate, or has to replace |
| An explicit right to export historical data | Trend data is the asset. Losing it resets every efficiency baseline to zero |
| Commissioning records and the sequences of operation | Tells a future engineer what the plant was meant to do, not just what it is doing |
The same reasoning applies to subsystems bought separately from the main automation contract, which is why the specification for a commercial access control system deserves the same scrutiny on credentials and interfaces as the plant it sits alongside.
Why the brochure and the meter disagree
Buildings underperform their design intent for reasons that are administrative more than technical. Alarms accumulate until nobody reads them. Temporary overrides entered during a fit-out stay in place for years. Sub-metering is installed at a granularity that cannot attribute consumption to anything actionable, so the reports get filed rather than used.
None of that is fixed by more sensors. It is fixed by naming, in the contract, the person responsible for acting on what the system reports, and by giving that person metering detailed enough to make a decision. The practical starting point for most existing estates is the energy layer, where the measurement infrastructure usually already exists.
Three questions worth asking early
Does a smart building have to be a new building?
No, and the majority of the market is not. Existing stock is where most of the activity sits, because controls, metering and analytics can be layered onto plant that has years of service left. The constraint on a retrofit is rarely the equipment; it is the quality of the documentation left behind by previous contractors.
Is the smart readiness indicator compulsory today?
Not currently. Under the recast directive it is an optional scheme, with member states free to run test phases, and several have. The dates to watch are the Commission report due by 30 June 2026 and the delegated act due by 30 June 2027 covering larger non-residential buildings.
Which single decision has the longest consequences?
Choosing whether the owner or the integrator holds administrative control of the system. Every other decision can be revisited at the next capital cycle. That one quietly sets the cost of every change for the life of the installation.
The buildings that will look well judged in ten years are unlikely to be the ones with the most technology in them. They will be the ones whose owners can still open the system, read the history and hire whoever they want to work on it.
Starting with the energy layer?
Energy management is where most existing buildings get their first measurable return, provided the implementation is structured properly.
Read our guide to implementing building energy management systems
