LoRaWAN Indoor Air Quality and CO2 Sensors: A Buyer's and Installer's Guide

LoRaWAN indoor air quality sensors measure CO2, temperature, humidity, TVOC and particulates wirelessly for years, and feed ventilation control in the BMS.

Indoor air quality (IAQ) has moved from a "nice to have" to a board-level concern: for occupant health and productivity, for compliance, and for the energy cost of ventilating buildings that are often half empty. Wireless LoRaWAN sensors have made monitoring every room affordable. This guide explains what to measure, which thresholds matter in the UK, how to choose and place sensors, and how to turn readings into automatic ventilation control.

Why monitor indoor air quality?

Health and wellbeing. Poorly ventilated rooms allow CO2, pollutants and airborne infections to build up.
Productivity and learning. Studies consistently associate high CO2 in offices and classrooms with reduced concentration and decision-making performance.
Compliance and guidance. UK building regulations, HSE guidance and school ventilation standards all point to CO2 monitoring as the practical way to show ventilation is adequate.
Energy. Ventilation is a large share of HVAC energy. Ventilating every room at its design maximum all day wastes energy when rooms are empty; demand-controlled ventilation driven by CO2 cuts that waste.
Evidence. Certifications such as WELL and RESET, ESG reports and tenant expectations increasingly call for measured, continuous IAQ data.

What should an IAQ sensor measure?

Parameter	Why it matters	Typical use
CO2 (carbon dioxide)	Best practical indicator of ventilation relative to occupancy	Demand-controlled ventilation, ventilation compliance
Temperature	Comfort	Zone control, comfort reporting
Relative humidity	Comfort, mould risk, virus survival	Humidity control, damp monitoring
TVOC (total volatile organic compounds)	Off-gassing from furniture, cleaning products, people	IAQ indices, purge cycles
PM2.5 / PM10 (particulates)	Outdoor pollution ingress, combustion, construction dust	Filter performance, health reporting
Formaldehyde (HCHO)	Off-gassing from new furniture and fit-out	New buildings and refurbishments
Light level	Daylight and lighting use	Lighting control, occupancy inference
PIR / occupancy	Whether the room is in use	Linking IAQ to occupancy, setback
Barometric pressure	Weather and pressure reference	Specialist uses

For most offices and schools, CO2, temperature and humidity are the essentials. Add TVOC and PM2.5 for wellbeing certifications, sites near busy roads, or new fit-outs. Multi-sensor devices often include PIR and light at little extra cost, which is useful for linking air quality to occupancy.

UK CO2 guidance in brief

There is no single legal CO2 limit for every building, but the guidance converges:

HSE guidance treats CO2 levels consistently below about 800 ppm as an indicator of a well-ventilated space, and levels consistently above about 1,500 ppm in an occupied room as a sign that ventilation should be improved.
Approved Document F (ventilation) of the Building Regulations recommends CO2 monitoring in offices and other occupiable rooms in new non-domestic buildings so occupants can see when ventilation is inadequate.
BB101 sets ventilation and CO2 performance criteria for school teaching spaces, expressed as daily averages and limits on time spent at high levels.
CIBSE guidance, WELL and RESET give further targets for higher-performance buildings.

Outdoor air in the UK is typically around 420 ppm, so indoor readings are best read as "how far above outdoors" a room has climbed. Use these thresholds to set traffic-light displays, alarms and control setpoints, and confirm the specific requirement for your building type with your designer.

Choosing a LoRaWAN IAQ sensor

CO2 sensor technology

Choose sensors with NDIR (non-dispersive infrared) CO2 measurement. Cheaper "eCO2" values estimated from TVOC are not true CO2 readings and are unsuitable for ventilation control or compliance. Check:

accuracy, typically ±(30–50 ppm + 3% of reading) for good NDIR sensors
automatic baseline calibration (ABC), which corrects drift by assuming the room returns to near-outdoor levels when empty. It works well in offices and schools that empty at night; in spaces occupied 24/7 (hospitals, data halls) use manual calibration instead
measurement interval and how it affects battery life

Battery life

LoRaWAN IAQ sensors typically last several years on their batteries at a 10-minute reporting interval. Life shortens with:

more frequent reporting
particulate sensors, which use a fan and draw more power (often mains or USB powered)
e-ink or LED displays that update frequently
poor radio coverage forcing high spreading factors (see LoRaWAN range and gateway planning)

Display or no display

Sensors with a screen or traffic-light indicator let occupants see air quality and open a window or take a break, which drives behaviour change in schools and offices. Plain sensors are better where tampering is a concern or the data is purely for control.

Popular models

Tyrrell Products stocks Milesight and Elsys LoRaWAN IAQ sensors, including:

Milesight AM100 series: compact temperature, humidity and CO2 sensors such as the AM100 temperature, humidity and CO2 sensor, ideal for room-by-room CO2 monitoring
Milesight AM300 series: multi-sensors measuring temperature, humidity, PIR, light, TVOC, barometric pressure and CO2, with variants adding PM2.5, PM10 and HCHO, and an e-ink display with a traffic-light indicator, for example the AM300 multi-sensor
Elsys ERS series: discreet room sensors, with CO2 variants, widely used in offices

Browse the full range in LoRaWAN air quality devices and indoor air quality. If you need wired sensors instead, BACnet and Modbus room CO2 sensors are available too.

Where to mount IAQ sensors

Placement matters more than the sensor brand.

Height: in the breathing zone, about 1.1 to 1.7 m above the floor for seated and standing occupants.
Away from people's breath: not directly beside a desk or at head height next to a seat, where exhaled CO2 gives false peaks.
Away from air flows: not near supply diffusers, open windows, doors or extract grilles, which give readings unrepresentative of the room.
Away from heat: not in direct sunlight, above radiators or near equipment, which distort temperature and humidity.
Representative position: an internal wall in the occupied part of the room. In large open-plan areas, use several sensors.
One per controllable zone: for demand-controlled ventilation, at least one sensor per zone that the ventilation system can control independently.

Integrating LoRaWAN IAQ sensors with the BMS

Monitoring alone shows the problem. Integration fixes it. With Niagara 4:

Receive the data through a LoRaWAN gateway and network server: an IONA-I controller with integrated LoRaWAN, a Milesight gateway with the Tyrrell Products LoRaWAN for Milesight driver, or MQTT from a network server.
Map each value to a Niagara point with units, tags (for example zone, air, co2, sensor) and history.
Alarm on high CO2, out-of-range temperature or humidity, and low battery.
Control: link CO2 to the AHU or fan coil ventilation demand, so fresh air rises as a room fills and falls when it empties.
Report: use histories and dashboards to show time above thresholds per room, by day and by month.

Demand-controlled ventilation with CO2

A simple, effective strategy:

Room CO2	Ventilation demand
Below about 600 ppm	Minimum ventilation rate
600 to 1,000 ppm	Ramp proportionally
Above 1,000 ppm	Maximum ventilation rate

Combine it with occupancy (PIR or people counting) so unoccupied zones drop to minimum immediately, and with outside conditions so the strategy does not over-ventilate in very cold or hot weather. On VAV systems the CO2 signal resets the zone's minimum airflow; on constant-volume AHUs it resets fan speed or fresh air damper position.

Demand-controlled ventilation often delivers some of the quickest energy savings available in a BMS, particularly in meeting rooms, classrooms, lecture theatres, gyms and any space with highly variable occupancy.

Commissioning checklist for IAQ sensors

Register and join every sensor on the network server, and label each with its room and DevEUI.
Check radio quality for each device (RSSI and SNR) and fix weak links before handover.
Allow settling time. NDIR CO2 sensors need a period after power-up to stabilise, and automatic baseline calibration needs several days of normal occupancy patterns.
Spot-check readings against a calibrated handheld instrument in a sample of rooms.
Set reporting intervals that balance responsiveness and battery life, typically 5 to 10 minutes.
Configure alarms for high CO2, temperature and humidity limits, and low battery.
Tag and name points consistently so dashboards, hierarchies and analytics work across the estate.
Test control actions, for example by raising a room's CO2 reading and confirming the ventilation responds.
Document sensor locations, settings and the battery replacement schedule in the O&M manual.

Reporting indoor air quality

Raw readings every ten minutes from hundreds of rooms are too much for anyone to read. Summarise them:

Report	Audience	Content
Live floor plan	Facilities team, occupants	Traffic-light CO2 and temperature per room
Weekly exceptions	Facilities manager	Rooms that spent more than a set time above CO2 or temperature thresholds
Monthly IAQ summary	Estates and HR	Percentage of occupied hours in each band, by building and floor
Annual certification evidence	Sustainability, ESG	Continuous data for WELL, RESET or tenant reporting

Rooms that regularly exceed thresholds point to ventilation faults, over-occupation or controls that need adjusting, and they are where engineering effort should go first.

Applications by sector

Schools and universities: CO2 displays in classrooms, compliance evidence, CO2-led ventilation in lecture theatres, and estate-wide dashboards for facilities teams.

Offices: meeting room ventilation by CO2, wellbeing reporting for tenants, WELL and RESET certification evidence, and occupancy insight from the same sensors.

Healthcare: waiting areas, clinics and staff rooms where ventilation and infection control matter; temperature and humidity in stores.

Retail and leisure: variable footfall areas such as gyms, cinemas and restaurants where ventilation should follow people numbers.

Heritage and listed buildings: wireless sensors avoid cabling through protected fabric.

Common mistakes

Using eCO2 sensors for ventilation control or compliance.
Mounting sensors next to people or in air streams.
Leaving ABC on in 24/7 spaces, where it slowly drags readings down.
Collecting data that nobody acts on. Connect it to control or at least to alarms and a monthly report.
Reporting too often, which shortens battery life without improving control. CO2 changes over minutes, not seconds; 5 to 10 minutes is usually right.

Frequently asked questions

What is a good CO2 level indoors?

Below about 800 ppm indicates good ventilation for the number of occupants. Consistently above about 1,500 ppm in an occupied room suggests ventilation should be improved.

Are LoRaWAN CO2 sensors accurate?

Sensors using NDIR measurement are accurate to roughly ±(30–50 ppm + 3%) when correctly calibrated. Avoid "eCO2" estimates from VOC sensors for anything important.

How long do LoRaWAN air quality sensor batteries last?

Typically several years at a 10-minute reporting interval with good radio coverage. Particulate sensors and frequently updated displays use more power.

Can LoRaWAN CO2 sensors control ventilation?

Yes. Once integrated into the BMS, CO2 readings can drive demand-controlled ventilation by resetting AHU fan speed, damper positions or VAV minimum airflows.

Where should a CO2 sensor be placed in a room?

In the breathing zone (about 1.1–1.7 m high) on an internal wall, away from people's breath, windows, doors, supply diffusers and heat sources.

How many CO2 sensors does a room need?

One per room is usually enough for meeting rooms and classrooms. Large open-plan areas, lecture theatres and halls need several, at least one per independently controlled ventilation zone, so that readings represent where people actually sit.

What humidity level should an office have?

Most guidance targets roughly 40–60% relative humidity for comfort. Persistently low humidity causes dry eyes and static; persistently high humidity increases mould and condensation risk.

What does a TVOC reading tell me?

TVOC (total volatile organic compounds) indicates gases released by furniture, cleaning products, printers and people. It is best used as a trend and to compare rooms, rather than as an absolute health figure, because sensors respond differently to different compounds.

Do I need a gateway for LoRaWAN IAQ sensors?

Yes. Sensors report to a LoRaWAN gateway and network server. An IONA-I controller can provide both inside the BMS controller.