What is BACS in Flanders and does it affect your business?
11 March 2026 · ⏱ 6 min read
What is BACS?
BACS stands for Building Automation and Control System. It means your building is set up so you can structurally monitor your energy use and technical installations. You see when consumption happens and can compare it with other days or with a target.
When something deviates, you get a signal (an alarm or alert). That's the starting point to act: you adjust a schedule or setting, or give a technician a targeted task. The goal is simple: installations only run when needed and don't keep running by accident.
BACS almost always consists of three parts:
Meters and sensors (and sometimes controllers)
Dashboards, comparisons, alerts, reports
Agreements around follow-up (who gets the alert, who checks, what's the action, when is it resolved)
From control to insight: BMS, EMS, BACS and Ella
This helps to distinguish the terms:
Mainly controls HVAC (heating, ventilation, air conditioning). Think schedules, setpoints, on/off and control.
Focuses mainly on energy data: measuring, analysing, reporting.
The package Flanders expects: measuring + comparing + alarms + follow-up + systems working together + indoor environment.
290 kW in Flanders: what counts and what doesn't?
Many companies start by adding up: all heating and cooling capacities together and checking if they exceed 290 kW. For Flanders that is not the right approach.
You only add up installations that are technically connected, and you do two separate checks: one for heating and one for cooling, each with a threshold of 290 kW.
Practically that means: 220 kW heating and 180 kW cooling is not automatically subject to BACS. But as soon as heating (or cooling) on its own exceeds 290 kW within one connected system, you may be in scope. This is an important starting point, because it determines your entire plan.
Scope check: are you in scope?
BACS applies in Flanders to certain non-residential buildings such as shops, warehouses, offices and businesses. To quickly check whether you may be in scope:
- 1.Check whether you have heating and/or cooling
- 2.Look up the nominal thermal capacity (technical data sheet, maintenance report, or nameplate)
- 3.Only add up installations that are technically connected
- 4.Assess heating and cooling separately
When do you need to comply?
Deadline for buildings already in scope (≥ 290 kW thermal capacity per system).
The threshold drops to 70 kW thermal capacity. BACS becomes relevant for many more mid-sized buildings.
Not compliant yet? No panic, but start now to become compliant. That's why it's smart to get your basics in order now: know what your capacity is, what's connected, and what measurements and follow-up you already have.
What are your options for compliance?
The most practical route. You meet the 7 technical requirements Flanders lists. That's the route most companies use, because it clearly describes what your system must be able to do.
You demonstrate that your building automation meets ISO 52120-1 class B. On top of that Flanders also explicitly requires A, B and G: measuring and storing energy, letting systems cooperate, and monitoring the indoor environment.
Flanders clarified two points that often impact installation work and cost in practice:
- —Small heat generators under 12 kW don't need to be measured or controlled separately if they aren't part of the main heating.
- —For indoor air quality, at least 1 sensor per 100 m² now applies, instead of in every room larger than 15 m² (connected to BACS).
Method 1: the 7 technical requirements
You can remember these seven points as: Measure → Integrate → Understand → React → Optimise
You must measure energy data correctly and keep it long enough. Electricity must be available at least every 15 minutes, other meters at least hourly, and data is kept for several years.
Systems must be able to exchange data (not locked to one brand or one closed solution).
You must be able to show and compare consumption, set alarms and have a clear follow-up procedure.
You must be able to detect efficiency losses and avoid systems working against each other (e.g. heating and cooling at the same time).
If you have renewable energy or waste heat, you must be able to use it more smartly (e.g. load shifting/storage).
From 2028 lighting in many spaces must switch off automatically when unoccupied (this doesn't necessarily have to be connected via BACS).
Temperature, humidity and CO₂ must be monitored with sensors and logging (with the 1 sensor per 100 m² rule).
What does this mean for your business?
If you want to tackle this practically, work in this order:
- 1.Scope check: heating and cooling separately, only connected installations
- 2.Inventory: what do you already have? (meters, sensors, any BMS control)
- 3.Quick wins: night consumption, peaks or schedules that keep running too long
- 4.Agreements: who follows up alerts and what's the default action?
Important: BACS is not "install and done". It only works if you can also demonstrate that you measure, signal and follow up in practice.
Where Ella fits in
BACS says what a building must be able to do: measure, compare, send alerts and follow up. But honestly: many companies have data… and yet energy often feels like a stress factor. You get a high bill, everyone looks at each other, and no one can say with certainty: "this is the reason." That costs time, frustration and often money.
That's why Ella is not another dashboard. Ella is an action-oriented layer on top of your energy and (where relevant) price data. Not more graphs to interpret, but clear alerts in plain language that point you straight to action.
Concretely, Ella helps you go from chaos to control:
You get a clear alert.
You immediately see when it happens.
You get context.
A short checklist to start with.
Example: your building is closed at night, but consumption stays high. BACS can detect that pattern. Ella makes it human and action-oriented: you don't just get "there's a deviation", but also where to start.
Curious what Ella can do for you?
Book a free 30-minute call and discover how Ella simplifies your energy management.
Book your slot →30 minutes, no commitment, at a time that suits you.