Modern businesses and the housing and utilities sector increasingly talk about digitalization, but in practice, most buildings are still equipped with conventional mechanical water and gas meters. Replacing an entire fleet of meters is expensive, time-consuming, and logistically challenging, especially for residential buildings, business centers, or industrial sites. Against this backdrop, retrofit modules for existing meters appear to be a reasonable compromise: they transform old meters into part of a unified resource monitoring system without requiring major repairs, and these modules become the digital source of consumption data that underpins analytics, billing, and automation. Thanks to them, organizations can gradually, without disrupting their budgets or users, transition from manual meter readings to fully-fledged smart metering. You can learn more about these modules on this source. 

How does the pulse output of water and gas meters work?

Most mechanical water and gas meters installed in recent years already have pulse reading capability, even if this feature has never been used. Inside the device, in addition to a mechanical roller indicator, a system is configured that generates an electrical pulse when a certain volume of water or gas passes through. This can be a reed switch, which is triggered by the rotation of a magnet built into the metering mechanism, or an optical sensor that reads special marks on a disk. Of course, this pulse itself is not sent anywhere; it merely closes or opens a contact, creating a series of "clicks" for the external device.

The retrofit module is essentially connected to this pulse output and converts abstract contact closures into meaningful data. The module contains electronics that count the pulses, time-trigger them, convert them into volume units according to the set pulse coefficient, and store the results in non-volatile memory. This data can then be periodically sent to the server or local controller via a selected communication channel.

The reader module: what it “sees” and how it stores data

The module's main task is to correctly interpret the meter's data. Each pulse corresponds to a fixed number of liters of water, cubic meters of gas, or another unit of volume specified in the meter's data sheet. The meter doesn't know when the user will be collecting the readings, so the module must be autonomous, energy-efficient, and smart enough to ensure every pulse is not lost.

In a typical scenario, the module maintains a cumulative pulse counter and simultaneously stores states for specific time intervals, such as by the hour or day. This allows not only for readings on a specific date but also for building a consumption profile, tracking peak loads, nighttime consumption, leaks, and other anomalies. Many modules maintain an internal event log, recording power failures, tampering, attempts to open the enclosure, and sensor line breaks. All of this is important so that the data can be used in legally binding accounting and dispute resolution situations.

Data Transfer: From Wired M-Bus to Wireless IoT

Once the module has counted the pulses and converted them into data, the question arises: how to deliver this data to the dispatching or billing system? Various architectures are possible here, depending on the type of facility, budget, and existing infrastructure.

In buildings with extensive utility networks, wired buses like M-Bus or Modbus are often used. In this case, modules are connected to a common line, through which the controller polls them at a set frequency, collecting readings for the entire group of meters. A wired system is especially suitable for areas with a high density of meters in a small space: apartment buildings, business centers, and industrial buildings. It is resistant to interference, is unaffected by radio signal strength within reinforced concrete structures, and integrates well with existing automation systems.

When cable installation is difficult or expensive, wireless transmission is used: for example, in private homes, remote buildings, and older housing with limited installation options. Here, the choice is often made in favor of narrowband IoT networks such as NB-IoT, LTE-M, and LoRaWAN, as well as radio solutions based on proprietary technology or using hubs and gateways. In some cases, especially for commercial properties, GSM modules can be used, transmitting data via a mobile network.

Each approach has its own characteristics: wireless networks allow for reduced installation but require more careful coverage and energy efficiency calculations, while wired solutions are easier to control but more difficult to physically implement in complex building architecture.

Integration of modules into a common resource accounting system

Connecting the module to the meter is just the first step. For the data to begin working for the business, it needs to be integrated into a unified resource accounting system. In a typical project, data from the modules is sent either to a local controller or to a higher-level server via protocol gateways. The software is then responsible for processing, storing, and visualizing the readings.

Modern systems allow for the integration of water, gas, electricity, and heat into a single platform, distinguishing between apartment and communal meters, and commercial and process metering. Modules serve as a source of "field" information, which is used to generate detailed reports: consumption by zone, period comparison, balancing between communal and individual metering, and loss detection.

Integration with billing systems automates billing: readings are no longer entered manually, reducing the risk of errors and eliminating "forgotten" apartments or contractors. For management companies and utility providers, this means reduced operating costs and greater billing transparency. End users now have a personal account where they can view current readings, consumption history, and projected future payments.

The role of modules in the concept of "smart home" and "smart building"

A smart home or smart building involves more than just lighting and climate control, but also intelligent resource metering. When modules are installed for water and gas, they provide the automation system with a new layer of information. If the controller detects a sharp increase in water consumption at night, it can initiate an automatic check or send a notification to the user. If unusual gas consumption is detected in non-residential areas, the system can switch the equipment to a safe mode and alert staff.

Smart scenarios based on meter data enable flexible management: adjusting heating and hot water modes based on actual consumption, detecting water leaks in irrigation systems, and monitoring compliance with gas limits in commercial properties. In office centers or shopping malls, this helps distribute costs fairly and transparently among tenants, motivate them to save energy, and generate ESG reporting.

Project economics: why retrofitting is often more profitable than replacement

A complete replacement of a fleet of meters involves not only the cost of the meters themselves, but also sealing, verification, dismantling and reassembling, the need to gain access to the premises, and the interruption of technological processes. In many cases, such an operation becomes a complex and lengthy project. Retrofitting with modules, on the other hand, allows existing meters to be used until the end of their verification interval, simply by adding a reading and data transmission device.

The economic impact is multifaceted. First, labor costs are reduced: no more site visits or manual meter readings. Second, losses from leaks and unaccounted consumption are reduced, as the system detects anomalies in near real time. Third, the number of disputes with consumers is reduced, as the data becomes transparent and systematized. Fourth, it becomes possible to optimize tariff plans and consumption patterns, adjusting them to the actual load.

Even at small facilities, such as a business center or residential complex, the cumulative savings over several years can easily outweigh the costs of installing modules and implementing software. And for large industrial facilities or urban infrastructure, the benefits are scalable and become a strategic factor in resource management.

Technical nuances of installing modules on existing meters

However, despite the attractiveness of the concept, it's important to pay close attention to the technical details. Not every older meter is equipped with a pulse output, and even if it is, it's important to ensure compatibility with the specific module. The signal type, maximum pulse frequency, voltage level, and presence of magnetic isolation are all checked. Sometimes, additional protection against interference and voltage surges is required, especially in industrial environments.

The physical location of the module is also important. For water meters, this often applies to damp, confined areas, where it's crucial to ensure the housing is sealed and the wiring is properly routed. Gas meters have special requirements for explosion protection, the use of intrinsically safe circuits, and certified equipment. Verification is also crucial: tampering with the meter's design is prohibited, so the module must be connected to the manufacturer's designated interfaces without breaking the seals.

Particular attention is paid to power supply. Energy efficiency is critical for standalone wireless modules: a device can operate on battery power for up to ten years if sleep modes, data transfer rates, and event processing are properly managed. In wired systems, power is often supplied via a bus, which simplifies operation but requires consideration of the total line load.

Data security and reliability

As soon as metering goes digital, the issue of security arises. Water and gas consumption data is important not only for financial purposes but also for user behavior analysis, so it must be protected. Integrity control mechanisms, secure transmission, and device authentication on the network are implemented at the module level. Any attempt to open a module or change its configuration must be recorded and reflected in the event log.

Reliability of measurements is ensured by calibration and proper pulse factor settings. It's important that the module accurately tracks the maximum pulse rate at peak consumption, eliminates false alarms, and filters out contact bounce. Otherwise, the system will generate an inaccurate consumption picture, leading to financial losses and conflicts. Therefore, during implementation, test measurements, comparisons with benchmarks, and verification of software integration are mandatory.

Implementation Path: From Pilot Project to Scaling

Experience shows that the optimal approach to upgrading existing meters begins with a pilot site. A representative group of meters is selected: several entrances, part of a workshop, or a separate building. Modules of various types are installed, communication channels are configured, and integration with the server and dispatcher interface is performed. During the pilot, real-world challenges are identified: communication specifics in a specific building, user behavior, and access nuances to the meters.

Once the system has demonstrated its functionality, a phased scaling can be initiated. The advantage of a modular approach is that implementation doesn't require a sudden shutdown of the entire facility: several nodes are upgraded today, and another section tomorrow, while the overall architecture and software platform remain unchanged. This reduces risks and allows costs to be spread out over time.

Bottom line: digital metering without a revolution in engineering systems

Retrofit modules for water and gas meters offer the opportunity to take a step toward smart metering without having to throw away thousands of still-functional devices. They seamlessly integrate into existing infrastructure, transforming mechanical meters into elements of a building's or enterprise's digital ecosystem.

As a result, the owner receives what a modern facility requires: a transparent picture of resource consumption, quick access to readings, analytics and automation tools, and the foundation for a smart home or smart building. And users and residents receive more transparent and understandable charges, the ability to monitor their consumption and, if desired, reduce their bills through a more responsible approach to water and gas use. All this makes upgrading existing meters with modules more than just a technical upgrade, but an important step toward smarter and more efficient resource management.