Home Assistant for business: home automation that works for your company

The heating runs all weekend. The server room air conditioning fails on a Friday evening and nobody knows until Monday. The storeroom lights stay on all night. Every business premises has its share of small leaks, in money as well as in risk.

Building management systems exist, but they are designed for large sites and large budgets. For small and medium-sized businesses, Home Assistant fills the gap.

Home Assistant in a nutshell

Home Assistant is open-source software that brings all your connected devices together in a single interface, whatever their brand.

Local: it runs on a small box installed on your premises. Your automations keep working if the internet goes down.
Open: the code is public and free. No licence, no mandatory subscription.
Universal: it talks to thousands of products and protocols, from Zigbee to Modbus, KNX and Wi-Fi plugs.
Programmable: you describe simple rules. “When the last badge has left, lower the heating and switch off the lights.”
Observable: everything is logged. Temperatures, energy use and door openings can be read on a dashboard.

What it changes on your premises

Four use cases come up in almost every business installation.

Energy. This is where the biggest savings are. Heating and air conditioning follow actual occupancy, not a timer set three years ago. Smart plugs cut standby power at night. A smart meter or clamp meters finally show who uses what, and when. The benchmark from the French government’s energy sobriety plan (in French) is simple: 19 °C in occupied rooms, 16 °C when empty, and 7% less energy for every degree lower.

Technical monitoring. A temperature probe in the server rack, a leak detector under the water heater, a check on the UPS or the cold room. If something goes wrong, the right person gets an alert on their phone, even on a Sunday.

Everyday security. Knowing that a door was left open, that a gate did not close, that there is movement in the storeroom at 3 a.m. Simulating presence during the annual shutdown.

Comfort and image. A meeting room warmed up before the first appointment. CO₂ levels tracked, with a reminder to open the windows. A “closing” button that switches everything off, so the last person out does not have to walk round every room.

Why Home Assistant rather than a proprietary solution

Branded hubs and manufacturers’ apps do the job, until the day they stop doing it.

No lock-in. You mix brands and switch between them without starting over. If a manufacturer shuts down its online service, your local devices keep working.
Your data stays with you. Occupancy times and door openings are not sent to a third party. That is a GDPR argument as much as a privacy one.
Controlled costs. You pay for the hardware and the set-up. No per-user or per-sensor licence.
An installation that grows with you. Start with three sensors and a thermostat. Add the rest once the need is proven.
A living project. Home Assistant ships an update every month and relies on one of the largest open-source communities.

Points to watch

Home Assistant comes from the consumer world. In a business, it must be deployed with the same rigour as any other system.

The network. Connected devices are rarely updated by their manufacturers. They belong on a separate network, never next to your workstations and servers.
Remote access. No open port on the internet router. A VPN or secure access with multi-factor authentication, nothing else.
Backup. A lost configuration means days of work to redo. It follows the same rule as the rest of your data: 3-2-1-1-0.
GDPR. A presence detector or a badge log reveals your employees’ habits. They must be informed, and the purpose must remain running the building, not monitoring people.
Regulated functions. Fire alarms, smoke extraction, intruder alarms approved by your insurer: these systems stay certified and independent. Home Assistant observes them, it does not replace them.
Support. There is no vendor to call when something breaks. You need a documented installation and someone accountable for it, in-house or at a service provider.

The hardware you need

A business installation comes down to four building blocks.

A dedicated box: a mini PC or an official Home Assistant device, on a UPS, in the server rack. Not a bare board sitting on a shelf.
A radio network for the sensors: usually Zigbee or Thread. Battery-powered sensors last several years and do not load your Wi-Fi.
Sensors and actuators: temperature probes, door and leak detectors, plugs and modules that measure energy use, thermostatic radiator valves or a gateway to your existing heating system.
A segmented network: a VLAN dedicated to connected devices, with explicit firewall rules.

Favour devices that work locally. A sensor that depends on its manufacturer’s cloud brings back the very fragility you were trying to avoid.

How much it costs

The software is free. The budget is split between hardware and set-up time.

For offices with a few rooms, expect, as a rough guide, a few hundred euros for the box and the radio network, then €10 to €30 per sensor or plug. These figures are indicative and must be confirmed by a quote.

The return shows up in three places. First the energy bill, which the history data lets you compare before and after. Then the incidents avoided: a leak caught in time, or a rack that does not overheat on an August weekend. Finally the time saved on closing rounds and manual adjustments.

One tip: measure for a month before automating anything. You will know where the real savings are, and you will have your baseline.

Where to start

Pick a single problem. Weekend heating or the rack temperature. Not both, not the whole building.
Measure. Install the sensors and let them run for a few weeks without controlling anything.
Alert. Add the useful notifications, each with a named recipient.
Automate. Write the first rules, keep them simple, and always keep a manual override.
Document and back up. Network diagram, device list, tested restore procedure.
Expand. Move on to the next problem once the first one is stable.

Five questions to ask yourself

Do you know how much energy your premises use when they are empty? Who is alerted if your server room goes above 30 °C on a Sunday? Are your current connected devices on the same network as your workstations? What happens to your devices if their manufacturer’s online service shuts down? Who in your company knows what is plugged in and how to get it running again?

If even one answer makes you hesitate, the subject deserves a review. That is where I start every business home automation project.