Submetering for EV Chargers: How to Bill Apartment Residents Fairly (Especially in India)

Currently, EV ownership is growing rapidly in cities across India, but many residential complexes are grappling with the basic question of how they can charge residents of EVs fairly without alienating non-EV owners or overloading the electrical infrastructure of the complex itself. Submetering provides a simple solution: measuring EVs differently from the overall electrical load of the complex, allowing each owner to be billed only for what they actually use.

In the following guide, we will explore what exactly EV submetering is, how it works in apartments, billing options, the regulatory environment in India, and how platforms like Savekar’s WhatsApp + UPI EV Charging can make it easy for all parties involved.

What is submetering for EV chargers?

In EV charging, a submeter is another word for "an additional meter, or metering functionality, which measures the energy consumed solely by a single EV charger, group of EV chargers, or a specific parking bay." Instead of EV charging being grouped under a building's master meter, a separate meter reading is provided, which can be billed separately to the EV owner.

Managers of a building welcome the idea of a submeter because they can allocate costs more accurately, which helps in the billing process. For residents, there is no longer the fear of subsidizing a neighbor's EV charging through inflated maintenance fees, as they can be billed separately for actual kWh consumed.

Why fairness in EV billing matters for apartments?

In multifamily buildings, the large and often unknown electrical load associated with EV charging has the potential to substantially impact the overall power bill for the common areas. When the overall bill is apportioned among the units, the non-EV residents may resent the fact that they are being forced to pay for the amenity of the EV residents, and this has created problems for the RWA.

A survey conducted among EV users in multifamily buildings has shown that the major cause for dissatisfaction among the users, and the reason they often complain to the property management, is the unclear pricing. On the other hand, the clearer the pricing, the more the non-EV residents are willing to pay for the property.

Common EV billing models in apartments

Before discussing submetering, it is important to briefly review the other options commonly considered by RWAs and building owners.

1. Free Charging as an Amenities Service

• The building covers all costs associated with electricity charges.
• This option is viable at the onset, but as more residents begin to charge up, costs escalate rapidly, and non-EV residents are likely to object very strongly.

2. Flat Monthly Charge for EVs

• EV owners are required to pay a flat fee every month, irrespective of the actual amount of power consumed by them.
• This option is easy to manage, but the non-heavy users feel they are being overcharged, while the heavy users feel they are being subsidized, which is unfair.

3. Shared Master Meter - Cost Split

• All EV chargers are connected behind the building’s master meter, and the cost of the extra power consumed by EVs is distributed among all apartments through the maintenance or utility bills.
• This option is easy to manage by the RWA but is regarded as the least equitable option, especially if only a few residents have EVs.

4. Submetered/individually metered charging (RECOMMENDED)

• Each EV charging station or parking spot is individually metered or has a metering feature, with users being charged per kWh or session based on the meter readings.
• All multifamily EV charging guides around the world highlight individually metered charging as the “cleanest fairness story,” as users pay for the usage, the model is scalable, and prices can be easily changed over time.

Bottom line: If your goal is fairness, transparency, and scalability, submetered / pay‑per‑use billing is the winning model for most apartment complexes.

How does EV submetering actually work?

Conceptually, EV sub-metering is simply an additional measurement point in the power flow path between the supply and the EV charger.

• Main Meter: Measures the total consumption of the building, i.e., flats, common areas, and EVs too, if not separated.
• EV Sub-Meter: Measures only the EV consumption of an individual, a group of people, or an entire block of EVs.
• CMS - Charge Management System: A set of software programs, such as Savekar, which collects data from the sub-meter or the charger session data, calculates the cost using a tariff, sends out bills, and collects payments.

In practice, you could use a physical meter on the EV feeder circuit, a smart charger with metering capabilities, or a combination of both, depending on the DISCOM and regulatory needs.

Indian regulatory context: meters, submeters, and DISCOM rules

India's guidelines for EV charging include the eligibility of group housing societies and RWAs, and the guidelines direct DISCOMs to provide connections for EV charging. In the present context, the users have the option to either use their existing flat meter for EV charging or to use a separate meter or submeter for the purpose. The state-wise regulations apply to the users in this context.

In the case of the use of separate meters for the purpose of EV charging, the users in some states have the advantage of availing the special EV tariffs, which are lower than the normal tariffs for the purpose. It has been stated in the sector analyses that the users would not be able to avail the discounted EV tariffs in the absence of a separate meter connection.

Why submetering is ideal for Indian apartments and gated communities.

For Indian RWAs and builders, submetering fits nicely with both regulatory and cultural imperatives of fairness.

• Transparent kWh-based billing: All can see exactly how many units were consumed and at what rate—no approximations, no hidden subsidies.
• Compatibility with EV tariffs: Having separate meters/submeters makes it easier to tie EV charging to DISCOM’s EV-specific tariffs available, thereby reducing the cost per unit for residents.
• Support for shared chargers: In many gated communities, a few shared chargers are more practical to begin with, rather than one per flat; submetering makes it easy to divide costs by actual consumption rather than by parking slot.

The cost of setting up submetering per EV point for Indian communities varies from ₹5,000 to ₹15,000, depending on technology and wiring complexities; this seems a small price to pay for the long-term benefits of clarity and reduction of disputes.

Flow of a fair submetered billing cycle

Here’s how a typical submetered setup can work in an Indian apartment with a platform like Savekar in the loop.

• The submeter or charger meter will record the consumption for a particular session.
• Savekar’s WhatsApp + UPI CMS can use these readings or the charger’s own meter to calculate per kWh charges, any parking/idling charges, and display these to residents in real-time via WhatsApp.
• Payment will be done via UPI (Google Pay, PhonePe, Paytm, etc.), and owners will retain 100% of revenue while paying a low annual CMS fee on chargers.
  

Practical steps for RWAs and property managers

1. Survey the demand from the residents and the pattern of parking

Before investing, it is suggested that a committee or a core group of EVs be formed to understand the number of EVs in the society, the type of EVs they own, and the pattern of parking (allocated parking versus open parking). This is suggested in the Indian and global guidelines for multifamily charging.

2. RWA approval and alignment of bylaws

A general body resolution should be passed allowing the installation of EV charging infrastructure, along with the rules for the hours of usage, the rules of "etiquette" (such as unplugging the charging point when the vehicle is fully charged), the rules for noncompliance, and the method of billing. Many societies have now clearly mentioned in their bylaws that the charging of the EV will be billed per kilowatt hour through a submeter.

3. Coordinate with DISCOM on metering and load

DISCOM approval is necessary for new connections or an increase in load. In some cases, there may also be guidelines for EV metering/sub-metering in the case of group housing. This generally includes:

• Conducting a load survey
• Sanctioning the increase in load, if necessary
• Clarification on EV tariff
• Approval for metering/sub-metering wiring

4. Select the hardware and sub-metering option

There are two options:

• Smart chargers that have in-built metering capabilities, which is applicable to most AC and DC charging options; or
• Sub-metering each charging point or cluster, which may be a regulatory requirement or applicable to older charging infrastructure.

Sub-metering cost per point is low in comparison to the overall project cost for the Indian market and may also be combined with other works, such as the distribution panel.

5. Implementation of a billing platform (this is where Savekar fits in)

A meter on its own does not guarantee fair and smooth billing; a platform to interpret the kWh readings and provide a transparent and auditable bill to residents, while also making payments easy and convenient for them.

The benefits of Savekar’s WhatsApp + UPI CMS are:

• Per Charger CMS is available at ₹1,999/annum with no revenue share; hence, 100% revenue can be retained.
• WhatsApp-based session management; residents can scan a QR code and track their charging and payments through a chat interface with no app installation required and no need to maintain a wallet float.
• Analytics and dynamic load management: real-time monitoring of energy consumption and optimisation of charger utilisation in accordance with sanctioned load.

With submeters or metered chargers, end-to-end fairness can be achieved.

Technical considerations when designing a submetered EV system

1. Electrical Capacity and Load Management

The electrical systems of apartment complexes can handle only a specific load, which means that adding even a small number of EV chargers may cause the system to surpass its authorised capacity if the installation process lacks proper management. All EV charger manufacturers now recommend dynamic load management as the standard solution, which enables chargers to decrease power consumption during peak periods while increasing power use during times of lower electricity demand.

Savekar’s solution allows dynamic load management, enabling you to charge the maximum number of chargers possible while still being able to track individual user charges.

2. Metering Accuracy and Compliance

It is important that sub-metering and charger metering are accurate enough to meet local standards, including revenue-grade metering standards where necessary. DC Fast Chargers are subject to standards such as IEC 61851, helping to assure accurate charger metering readings for billing purposes.

3. Time of Use (ToU) Pricing and Tariff Complexity

Some utilities have ToU pricing, where the cost of electricity is lower at night and higher during the day. Complex submetering systems also have the capability to take this into account when charging per session. However, if you have simple mechanical submeters, it is also difficult to handle ToU pricing. In this case, it may be necessary to manually calculate the costs.

A cloud-based CMS like Savekar would be able to handle tariff complexity, ToU pricing, and also provide a simple WhatsApp message for the residents.

4. Access Control/User Management

Access control systems for networked charging stations in a multifamily setting typically require RFID cards, mobile apps, or QR codes. In the case of a CMS like Savekar, the system would be much simpler. It would require a QR code linked to WhatsApp, so any resident with a smartphone and a UPI would be able to authenticate.

Where Savekar shines in the submetering story

Savekar is being marketed as an Indian-centric B2B EV charging network, placing a high emphasis on the use of WhatsApp + UPI as a method of managing EV charging, rather than requiring residents or guests to use a separate app or maintain an in-app wallet.

In the context of apartments or gated communities using submetered EV chargers, there are a number of specific benefits:

• Ease of use: Residents simply scan the QR code on the charger, the chat opens in WhatsApp, the charge begins, and the payment is made via UPI at the end of the charge session, all of which is fully compatible with any UPI app (GPay, PhonePe, banking app, etc.).
• No wallet required: Residents simply pay as they charge without requiring a prepaid wallet or balance being locked away in a separate app.
• Owner-friendly economics: For just ₹1,999/year per charger for CMS, with 100% revenue going back to the RWA, submetered billing combined with strong ROI is possible.
• Analytics + load management: With live analytics and load management, you can fine-tune pricing and load as resident EV demand grows.

Savekar becomes the missing link between electrical engineering and resident experience when used with submeters or smart chargers, converting metered readings into simple, WhatsApp-based bills everyone can understand and trust.

Frequently Asked Questions:

1. What is the difference between metering and submetering for EV chargers?

Mostly, metering means the principal utility meter, which measures the consumption of the whole building or set of buildings. Submetering involves installing additional meters further down the chain, e.g., per charger or per cluster of chargers, to separate EV charges from flat charges.

2. Is submetering of EV chargers mandatory in Indian apartments?

It is not universally mandatory, but according to the Indian guidelines, it is possible to implement it by either using the existing flat meter or by installing separate meters/sub-meters for EV charging in group housing societies with the coordination of DISCOMs. It is believed that submetering is more beneficial as it allows discounted EV tariffs, as well as a much clearer case of the fairness of billing.

3. What is the cost per EV submetering point?

For Indian gated communities and apartments, the cost of submetering hardware and installation will vary from ₹5,000 to ₹15,000 per EV charging point. This is a one-time cost, which will pay for itself through the avoidance of disputes and accurate billing over many years.

4. Can we share a single charging station and submetering for many residents?

Yes. One or more shared charging stations can still be used, and accurate billing can be done by logging the identity and kWh consumed per session through a networked charging station + CMS like Savekar, along with a submeter at the feeder or per charging station level. Each session is accounted for per resident, and the RWA can send out invoices or enjoy the benefits of instant UPI transactions.

5. Do we need a separate app for residents if we are using Savekar?

No. The Savekar solution provides a complete system that enables users to perform all necessary functions without needing additional application installations. Residents need only scan a QR code on the charger, interact through WhatsApp to track the session, and pay through any UPI-based app.

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6. How do Time of Use Tariffs impact EV billing for submeters?

If your DISCOM provides a Time of Use tariff structure, the cost of electricity depends on the time of day. For instance, the cost of electricity is lower at night and higher in the evening. With the help of smart submeters, a higher unit cost of electricity can be used for EV charging.

7. What if our building’s electrical capacity is low?

In the context of existing apartments, low capacity is a common issue. Rather than over-investing in panel upgrades, it is possible to have a combination of dynamic load management and submetered billing, allowing more EVs to be charged at a lower capacity than the sanctioned load. Savekar’s CMS provides the facility of dynamic load management.

P.S. Technical deep dive for engineers & consultants

If you are an electrical consultant, facility engineer, or a member of an advanced RWA, here are a few more technical considerations specific to submetered EV charging:

• Meter Class/Topology: Revenue-grade meters (Class 1.0 or higher) are required for three-phase AC or DC measurement as applicable.
  
• OCPP Chargers: Most of the EVSEs available today support OCPP protocols and have metering capabilities and support sub-metered billing. Make sure the CMS you have or plan to install, such as Savekar, supports metered values and relates them to individual users and matches them with sub-metered values.
  
• Earthing, Protection, and Safety: DC Fast Chargers must comply with IEC 61851 standard requirements for overcurrent protection, overvoltage protection, earth leakage protection, and insulation monitoring, which provides protection to residents while also providing accurate metered values.
  
• Data Retention and Auditability: For long-term fairness, it is recommended to design the system to retain logs on a per-session basis, including time, duration, kWh, tariff applied, and user.

With good electrical engineering, compliant sub-metering, and a resident-friendly billing layer such as Savekar’s WhatsApp + UPI CMS, you can create an EV charging infrastructure that is not only sound from an engineering and regulatory perspective but also socially and financially sustainable for your apartment community.