Frequently Asked Questions from Planners
37 questions that specialist planners, integrators, and operators ask us before issuing a request for proposals—regarding design, operation, commissioning, interfaces, and commercial matters. Each answer is provided in a few sentences, with a link to the page that explains it in detail.
Design and Quantity
5 QuestionsHow many CO2 sensors do I need for an open-plan office measuring 200 square meters?
At least one—that’s the minimum requirement based on two standards. WELL v2 requires one sensor per approximately 325 square meters, while RESET Air requires one per regularly used room type, with a maximum of 500 square meters per sensor. If the space is used for different purposes—such as a meeting area, break room, or reception area—each zone counts as a separate measurement location and requires its own device.
How many receivers do I need per floor?
We’re planning for a radius of about 12 meters per EnoDisc®, which covers roughly 450 square meters. Here’s the calculation: usable floor area divided by 450, rounded up, plus one dedicated receiver for each structurally separate area. Solid walls, elevator shafts, and firewalls significantly attenuate the signal; in practice, fewer receivers are often sufficient, but this can only be confirmed by measurements taken in the completed building.
Is one sensor per meeting room enough?
Yes. In the basic configuration, each meeting room measures CO2, temperature, and humidity with a single device; open areas are monitored for temperature and humidity. A meeting room counts as its own measurement location, even if it is small—this is also the approach taken by RESET Air.
How do I plan the sensor system for a stairwell?
Separate it from the floor. A stairwell is a separate area with solid walls, often with fire doors in between; its area is not included in the floor’s calculations. Anyone wishing to take measurements there—such as radon levels in the basement or motion detection for lighting—should plan for a separate receiver per section and verify the signal range on-site. The same applies to utility rooms and underground parking garages.
How many gateways do I need for an eight-story building?
Eight—we assume one gateway per floor. Technically, a VL-700 BASE can support up to 32 receivers and 500 sensors, covering multiple floors; however, this is a limit, not a design goal. Each floor can be configured as a separate unit, commissioned individually, and maintained locally; a malfunction affects only one floor, and there is room for future expansion.
Operation and Maintenance
6 QuestionsHow long does a sensor’s battery last?
For devices powered solely by batteries, we estimate a typical minimum lifespan of five years; a sensor that transmits less frequently will last longer. Devices with a solar cell ideally do not require a backup cell at all; in that case, the cell’s service life is limited to the ten years specified by the manufacturer. The cell type and number are listed in the device’s data sheet.
How can I tell if a sensor has failed?
A malfunctioning wireless sensor does not report a fault—it does not report anything at all. That is why every device sends a status signal and repeats its last value at least once every twelve hours, even if nothing has changed. The Alarms page of the dashboard lists all sensors that have not reported at their expected intervals; this list is usually empty. Before handover, determine who will view it and how often.
How often does a CO2 sensor need to be calibrated?
That is up to the operator: Automatic calibration is not currently enabled for our sensors. Calibration is initiated on the device using the service button; fresh air serves as the reference—no test gas or removal of the sensor is required. The dashboard will notify you if it has been too long since the last calibration. Include calibration as a maintenance task in your maintenance schedule and in your request for proposals; short videos on this topic are available in the video library.
Who replaces the batteries, and how often?
Replacement is based on condition, not on a schedule. The maintenance page lists every battery- or solar-powered sensor along with its current voltage and status (OK, Warning, or Critical); replacement occurs when a device enters the Warning status. The maintenance schedule specifies who performs the replacement—either the operator themselves or us as part of a maintenance agreement. Factor in accessibility: Replacing a sensor located under a ceiling eight meters high costs more than the battery itself.
Is there a fault message sent to the control system?
Yes, but not as a switch you flip. If the alert is to be sent not only to the dashboard but also to the building management system, we’ll set that up together with you as part of the project—for example, via a second MQTT broker that receives only fault alerts, separate from the measurement values. This should be included as a separate item in the scope of work.
How long will replacement parts be available?
Electronic components are discontinued, so we do not guarantee spare parts across the entire service life of a system, but rather on a project-by-project basis. For larger systems, we agree on a stockholding arrangement with a fixed quantity and duration—this can be specified in the scope of work.
Commissioning
5 QuestionsHow do I program a sensor?
Generally, you don’t have to do it yourself: We handle setting up the sensors, registering the receivers, assigning rooms, and configuring data transfer during commissioning. For larger systems, the configuration file is created in advance at the office, and it’s imported on-site instead of programming each device individually—the difference between one day and one week on the job site.
How long does commissioning take per floor?
We deliberately do not provide a flat rate per floor: The duration depends on the type of sensors and whether data can be imported in advance. Once the floor plan and desired configuration have been discussed, we’ll provide you with an estimate for your building within one to two days.
Do I need a laptop on site for the setup?
No. You don’t need to provide anything: We typically handle the setup ourselves and bring all the necessary equipment, including a laptop and wireless technology.
Can the electrician do this on his own, or do you need to help?
The division of labor is clear: The electrician installs and connects the equipment; we get the system up and running. Programming, configuration, and commissioning are tasks that DEUTA Controls handles as a paid service—not the operator and not the installer. Include this service as a separate line item, not as an add-on to the delivery.
How do I keep track of which sensor is installed in which room?
From the system’s configuration file. It lists every sensor and its location, every receiver and its address, and the gateway settings; it can be backed up and restored. Request this file as part of the documentation—it serves as an inventory list, room assignment guide, and recovery tool if a gateway needs to be replaced.
Technical Limitations
6 QuestionsHow accurate is the CO2 sensor?
Typically ±30 ppm plus 3 percent of the measured value; guaranteed to be no more than ±45 ppm plus 3 percent. At 1,000 ppm, this typically amounts to about 60 ppm and a maximum of 75 ppm—more than accurate enough for making ventilation decisions. WELL requires 10 percent at 750 ppm; the EnoSense® CO2 also meets this requirement, with a maximum value of 9.0 percent.
How often does a sensor transmit?
The reporting interval is fixed for each device and is specified in the data sheet. Signals are transmitted whenever the measured value changes and additionally as a status check, at least once every twelve hours. Depending on the type, the interval can be as short as a few minutes; the radon sensor reports only every few minutes because its measured value changes slowly. The reporting interval determines the power consumption and thus the power supply.
What happens during a power outage?
The system stores sensor assignments, receivers, and data transfers in non-volatile memory and automatically restarts once power is restored; nothing needs to be reprogrammed. The sensors themselves are powered by solar cells or batteries and continue to take measurements. The measurement values from the outage period are lost—if you require complete data coverage, ensure the gateway and network equipment have an uninterruptible power supply. This is a matter of electrical planning.
How many telegrams can the radio band handle?
A fully equipped floor with 500 sensors, each transmitting on average every four minutes, generates 7,500 telegrams per hour; with three transmissions per telegram, that number rises to 22,500. At about one millisecond per telegram, that amounts to roughly 22 seconds per hour—just over half a percent of the allowed transmission time. Each telegram is sent three times with a random offset; two sensors that overlap on the first attempt will not overlap on the second.
How secure is the radio link against eavesdropping?
Any receiver within range can read an unencrypted radio telegram—it receives a measured value and a device ID, but no access to the system and no personal data. The EnOcean standard requires encryption, and we are gradually upgrading our components to comply with it under the Cyber Resilience Act. We’ll list which devices currently use encryption for each item—please check the status before you put the project out to bid.
How long are measurement values stored?
The gateway maintains its own history as files on the device, with automatic rotation of the oldest entries; this data feeds the history views in the dashboard. This history is intended for looking back—a week, a heating season—not as a long-term archive; how far back it goes depends on the number of sensors and the reporting frequency. If you need data spanning years, store the values in the target system, and that is exactly where data retention should be specified in the request for proposal.
Interfaces
5 QuestionsWhich MQTT topics are used?
The gateway publishes every received measurement value in JSON format to the broker of your choice. The topic structure is a system setting and is defined during setup; there are three formats, all of which carry the same payload. This allows your integrator to know what structure to expect before commissioning.
Is there a BACnet object list?
BACnet is available as a data protocol alongside MQTT, KNX, and Modbus TCP and includes an object model, meaning it provides the sensor value along with its unit and status. The object list for your system is generated during configuration; be sure to explicitly request it as a service in the request for proposals, along with the format and naming conventions for the data points.
What Modbus registers are there?
Modbus TCP only recognizes registers—that is, numbers associated with an address; their meanings are listed in a table provided with the system. For single-room control, all parameters and statuses for up to 16 rooms are available for reading and writing via Modbus TCP. Request the register list as a service item in the request for proposals.
Can I retrieve data via REST?
Not yet: A REST interface is in the works. Currently, values are transmitted via MQTT, BACnet, KNX, or Modbus TCP. If your target system is based on REST, please contact us for an update.
Is there an interface specification available for download?
The ECS software user manual describes configuration and data transfer and is available in the Download Center. The measured values are sent to the MQTT broker in JSON format; topic structure as well as object and register lists are defined on a per-system basis and should therefore be included as a service in your scope of work, not in a general document.
Business and Law
5 QuestionsIs there a five-year warranty?
We don’t specify a flat figure—such as five years. We agree on the duration on a project-by-project basis; if you ask about it when requesting a quote, it will be included in the quote.
Where are the devices manufactured?
In Germany. The exceptions are the exware and VL-700 BASE control systems, which are manufactured by EXOR in Italy.
Is there an environmental declaration or EPD?
An EPD in accordance with ISO 14025 is not available for our devices.
Are the devices RoHS-compliant?
Yes. Our devices bear the CE mark in accordance with the Radio Equipment Directive 2014/53/EU and comply with the substance restrictions set forth in 2011/65/EU, as amended by Delegated Directive 2015/863/EU, commonly referred to as RoHS 3. Both are specifically mentioned in the Declaration of Conformity for the respective device in the Download Center. The CE declaration is not valid outside the EU; each frequency variant has its own country-specific approval.
How do I dispose of the sensors at the end of their useful life?
Do not dispose of them with regular trash. As a manufacturer, we are listed in the German Register of Waste Electrical and Electronic Equipment (WEEE), Reg. No. DE 51104067; we will coordinate the return and disposal with you. Batteries must be removed beforehand and disposed of separately.
Usage
5 QuestionsIs this suitable for a school?
Especially there. In a classroom, more people are seated in a smaller space than in an office, CO2 levels rise faster, and ventilation usually comes through the window. In that case, the display in the room is the actual tool: it tells the class when to ventilate and, afterward, lets the user know if it worked. Wireless devices require no new wiring—installation can be completed during a single summer break. For rooms on the ground floor or in the basement, radon levels should also be taken into account.
Can I use this to bill for desk sharing?
The table sensors provide the foundation for this: They report occupancy and time for each workstation, and the data is sent in JSON format to the MQTT broker of your choice. The billing itself—reservation reconciliation, cost centers, space allocation—takes place in your target system, such as your workplace management system. We provide the reliable occupancy data, not the billing.
Does this work in the server room, too?
Yes, with the right parameters: CO2 is measured by people, not by technology. In the server room, temperature and humidity (EnoSense® Temp/RH), current per phase (EnoSense® 3PH Current Sense), and access (motion detectors) are the relevant parameters. Technical rooms, like stairwells, are planned as separate zones: use a dedicated receiver and check the on-site radio signal path, as metal cabinets and shaft walls cause significant signal attenuation.
Can I use it to control the heating?
Yes. The VL-700 BASE uses the ECS software to control up to 16 rooms locally: Actuators, temperature sensors, window contacts, and setpoint adjusters are assigned to each room, with time-dependent setpoints. The window contact ensures that the heating system does not work against the open window when ventilating. All parameters and statuses are available to the building automation system via Modbus TCP for both reading and writing.
Is there a reference project I can look at?
Yes: the University of La Laguna on Tenerife—70 areas in 14 buildings, continuously monitored for radon and CO₂, without any new cables, without a new SSID, and without a new IP address. Rollout in four weeks, about 30 minutes per area. The university itself discusses the system; upon request, we’ll put you in touch for a conversation.
Can't find your question here?
Then ask us directly—we’ll respond from Hille, not from a form-based inbox. Include a floor plan, dimensions, and the target system, and you’ll immediately receive a recommendation for the number of units, a list of order numbers, and a quote.
Answers current as of: September 24, 2026. The linked pages and the devices’ data sheets are authoritative.