Wireless environmental monitoring system for a warehouse or plant: WiFi or LoRa, and what it costs per point
A wireless environmental monitoring system is a set of battery or mains-powered sensors that send temperature and humidity to a gateway or straight to your network, with alarms when a value leaves its range. For a warehouse the decision is between WiFi loggers, which suit up to a dozen points near existing access points, and 868 MHz LoRa sensors, which cover a whole hall from one gateway at a lower cost per point.
In short
- WiFi loggers need mains power and WiFi coverage at every point. Right for 3–12 points in offices, cold rooms next to a wall socket, and small warehouses.
- LoRa at 868 MHz reaches up to 1 km in open space and through several walls; one gateway takes up to 32 battery sensors. Right for halls, yards and racking with no sockets.
- Budget per measuring point: roughly EUR 125–160 for a WiFi or LAN logger and a lower per-sensor cost on LoRa once the gateway is paid for.
- Every wireless system needs the same three things: a local read-out that works without the internet, alarms on two channels, and a history you can export for an audit.
What a wireless monitoring system consists of
Four parts, whichever radio you choose. Sensors measure temperature, humidity and optionally leak, door or smoke. A network path carries the readings: the sensor's own WiFi, or a LoRa link to a gateway that sits on the LAN. A place where the data lands: the device's own web page and memory, your monitoring platform, or a cloud service. And alarms: e-mail, SMS or push when a threshold is crossed or a sensor goes silent.
The part people forget is the fourth. A system that only shows a dashboard is a thermometer with a longer cable. The value is in the alarm at 02:40 when the cold store compressor stops, and in the exported history a week later when the customer asks what happened to their pallet.
WiFi or LoRa: the decision table
| Criterion | WiFi logger | LoRa 868 MHz sensor + gateway |
|---|---|---|
| Power at the point | Mains adapter (or PoE on LAN variant) | Battery, years depending on interval |
| Range | Within access-point coverage, 2.4 GHz | Up to 1 km open space, hundreds of metres indoors |
| Through racking and walls | Weak; steel racking attenuates 2.4 GHz badly | Good; sub-GHz passes concrete and steel far better |
| Number of points | One device per point, each on the WiFi | Up to 32 sensors per gateway |
| Reading interval | Seconds to minutes | Minutes; 1 % duty cycle limits airtime |
| IT involvement | Each device joins the corporate WiFi | One gateway on the LAN; sensors are radio-only |
| Extra sensors per device | Up to four (leak, door, smoke, second probe) | Depends on sensor model |
| Sweet spot | 3–12 points, offices, cold rooms, labs | Halls, yards, racking, many points, no sockets |
The 1 % duty cycle is a legal limit, not a product limit. ETSI EN 300 220 restricts a device in the common 868 MHz sub-band to transmitting 1 % of the time, about 36 seconds per hour. For a sensor that sends a few bytes every five minutes this is irrelevant; it is what lets the battery last for years. It only matters if someone promises you second-by-second updates over LoRa.
A common mixed layout: WiFi or LAN loggers in the cold rooms and the office server closet, where sockets and coverage exist, and a LoRa gateway with battery sensors across the racking and the loading dock.
How many points a warehouse needs
The honest answer comes from a temperature mapping, which the pharmaceutical GDP guideline requires before a warehouse is used and which is good practice everywhere else. Place a dozen loggers for a week in summer and a week in winter, and the map shows where the hot and cold pockets are: under the roof, next to the dock doors, at the end of the aisle furthest from the heater. Permanent sensors go at the points with the greatest fluctuation.
Without a mapping, a working rule for a single hall: one point per 500–1 000 m² of floor, plus one at the top of the racking in the warmest zone, one at each dock door, and one per cold room or climate-controlled cage. A 5 000 m² hall with two docks and one cold room typically lands at 8–12 points, which is exactly the range where LoRa starts to beat WiFi on cost and installation time.
What it costs per point
Prices below are list prices for EnviSensor devices, net, and serve to size the budget rather than replace a quote.
- WiFi point: EnviSensor WiFi at EUR 140 with temperature, humidity and up to four sensor inputs. Add EUR 30 for a leak sensor or a temperature-humidity probe.
- LAN point in the cold room or closet: EnviSensor Mini TH ETH at EUR 125, PoE variant available.
- LoRa hall: one EnviSensor Radio gateway at EUR 190 for up to 32 sensors, plus battery sensors per point. The gateway cost is spread across every point you add later.
- Software: zero for local operation and for the CE MonitorApp free tier with 60 days of history; a paid tier if you want SMS and longer retention. Installation time, not licences, is the larger hidden cost.
A 10-point warehouse therefore lands between EUR 1 300 and EUR 2 000 in hardware. One rejected pallet of temperature-sensitive goods usually costs more.
Where wireless systems fail, and how to plan around it
- Coverage assumed, not measured. Steel racking full of stock is a Faraday cage at 2.4 GHz. Walk the hall with a sensor and a phone before you order twenty. For LoRa, mount the gateway high and central, not in the office at one end.
- A dead sensor that nobody notices. Alarm on silence: if a point has not reported for 30 minutes, that is an alarm, not a blank on the chart. Battery level should be a reported value, not a surprise.
- Alarms that depend on the internet. The gateway or logger should send e-mail on its own from the LAN. Cloud push is a second channel, not the only one.
- WiFi password rotation. When IT rotates the corporate WiFi key, every WiFi logger drops off. Put sensors on a dedicated SSID with its own key, or use LAN and LoRa where you can.
- No export. When the auditor or the customer asks, the system must produce a CSV or XLSX for a date range. Check this before buying, not during the complaint.
Frequently asked questions
What is a wireless environmental monitoring system?
A set of sensors that measure temperature, humidity and other conditions and send readings over WiFi or a sub-GHz radio such as 868 MHz LoRa to a gateway or your network, with alarms when values leave their range and a history you can export.
WiFi or LoRa for a warehouse?
WiFi for a few points with sockets and access-point coverage, such as cold rooms and offices. LoRa for a hall with many points, steel racking and no power at the measuring spots; one gateway covers up to 32 sensors.
How far does a LoRa 868 MHz sensor reach?
Up to about 1 km in open space and typically hundreds of metres inside a hall, through walls and racking, depending on the building and gateway placement.
How many sensors does a warehouse need?
Ideally as many as a temperature mapping shows. As a rule of thumb, one per 500–1 000 m², plus the top of the racking, each dock door and each cold room; a 5 000 m² hall usually needs 8–12.
Does a wireless monitoring system need the cloud?
No. Loggers and gateways can serve their readings on a local web page, over SNMP and as JSON, and send e-mail alarms directly. The cloud adds remote access and multi-site views but is optional.
Related pages
EnviSensor Radio
LoRa gateway for up to 32 wireless sensors, 1 km range.
868 MHz LoRa sensors
Range, spreading factor and the limits of the band.
Distribution centres
Monitoring for warehouses and logistics.
Need monitoring at your site?
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