Smarty meter and your electric car: measuring and reimbursing home charging, with or without a smart meter

The Smarty meter cannot tell which part of your consumption goes into your electric car: it measures the whole home in 15-minute intervals. To reimburse home charging for a company car, what matters is not having a smart meter, but measuring the kWh charged into the car and multiplying them by the right price.

This article explains what Smarty does and does not do, how charging affects the bill under the capacity-based network tariff, the three ways to measure charging, what happens for cross-border employees whose homes often have no smart meter, and how to justify a reimbursement without a dedicated meter. Voltaback, which reimburses home charging for more than 200 companies, measures without a smart charger or box, with or without a smart meter.

Smarty, Luxembourg's smart meter

Smarty is the communicating meter installed by Luxembourg's grid operators: mainly Creos, plus the Diekirch, Ettelbruck and Sudstroum networks, coordinated by the Luxmetering grouping. The mass roll-out took place between 2017 and 2020.

Today more than 98 % of the country's electricity meters are Smarty meters, about 343,700 electricity meters at the end of 2024. The very few non-communicating meters left may be charged a tariff supplement. Source: Luxtoday, smart meters in Luxembourg.

For employees living in Luxembourg, the question "do I have a smart meter?" is almost always settled. It matters mostly for cross-border workers, who make up 49 % of employees and charge on their own country's grid.

What Smarty measures and who sees the data

Smarty records consumption per quarter-hour and sends it to the grid operator, which passes it on to the supplier for billing. Customers see their load curve in the grid operator's customer portal (myCreos at Creos) and can simulate scenarios there, such as the effect of an electric car or a heat pump on their reference power.

The employer has no access to this data, and rightly so: a load curve reveals when someone is at home, asleep or cooking. As the next section shows, it would also be useless for reimbursing a company car.

Smarty+: real-time data, but no allocation

Since 2021, Creos and the other grid operators have offered the Smarty+ add-on. The dongle plugs into the customer port of the Smarty meter, connects to the home Wi-Fi and shows consumption in real time in an app; the grid operator supplies the code needed to read the data. At launch it cost €35, and it was developed by Nexxtlab, a Creos subsidiary. Source: Fedil, launch of Smarty+ (2021).

Smarty+ helps spot load peaks and plan charging, and some wallboxes use the same port to adapt their power to the home's consumption. But Smarty+ cannot separate the car's consumption from the rest of the household either.

Does the Smarty meter recognise an electric car?

No. Smarty records the whole home's consumption every 15 minutes and sends it to the grid operator and supplier. It does not separate the car from the oven, the heat pump or the water heater.

A charging session can sometimes be spotted on a load curve: a plateau of 3 to 11 kW for several hours at night. But a guess is not enough for a reimbursement:

• a tumble dryer or heat pump may be running at the same time;
• a private car in the household may use the same charging point;
• the employer has no access to the Smarty data of an employee's home, and should not, from a GDPR standpoint.

Smarty is a good basis for knowing the price the employee pays, not for isolating the kWh of the company car.

What charging changes on the bill

Since 1 January 2025, Luxembourg's network tariff has been capacity-based. It includes:

• a fixed monthly fee based on the home's reference power, at least 3 kW, assigned automatically by the grid operator;
• a fee per kWh consumed, 0.051 € excluding VAT at Creos;
• a supplement of 0.0765 € excluding VAT per kWh drawn above the reference power, calculated per quarter-hour.

Source: Creos, guide to the tariff structure.

Source of the amounts: Switchr, Creos network tariff.

In practice, a kWh charged at night on a dual-rate offer costs about 0.19 € including VAT, barely less than during the day (about 0.20 €). If charging pushes the home above its reference power, that kWh rises to about 0.27 € including VAT. Two employees with the same car can therefore pay very different prices. The full calculation is in our article on the price per kWh of charging.

Dynamic tariffs need a smart meter

Some suppliers offer dynamic tariffs indexed hour by hour to the wholesale price of the Germany-Luxembourg price zone. They require a Smarty meter, since consumption has to be known per quarter-hour. For a fair reimbursement, you then need the price actually paid at the time of charging, not an average. Our article on off-peak charging covers the useful time slots.

Do you need a higher reference power to charge?

Not necessarily. An 11 kW wallbox starting at 10 pm alongside the dishwasher will almost always exceed a 3 kW reference power. There are two options:

1. Limit the charging power: charging at 2.5 to 3 kW on a heavy-duty socket or a capped wallbox adds about 150 km in a 10-hour night for a car using 18 kWh per 100 km, charging losses included.
2. Accept a higher reference power: useful for high-mileage drivers, but the fixed monthly fee goes up, by about €65 excluding VAT a year from 3 to 7 kW.

Worked example of an overrun: if 2,700 kWh a year are all charged above the reference power, the supplement costs 2,700 x €0.0765 x 1.08 = about €223 a year. Moving to 7 kW costs about €70 including VAT. In that case, switching pays; a driver who charges slowly and stays below the threshold does not need it. The simulator is in myCreos.

For a company car, this is also a reimbursement issue: if the driver pays an overrun supplement because of the car, that cost is real and must be counted. A single flat price cannot see it.

Notifying the grid operator

Whatever the meter, any wallbox of 7 kW or more on three-phase, or above 4.6 kW on single-phase, must be declared to the grid operator in advance, through myCreos at Creos. Only an approved electrician may install it, and they report completion through the SmartyPro app. New requests require an Energy ID from leneda.lu. Source: Creos, charging your car.

Cross-border staff: often without a smart meter at home

Cross-border workers charge on their country of residence's grid, where smart meters are not always standard:

• In Germany, a smart metering system is only mandatory for households using more than 6,000 kWh a year; below that, the metering operator decides. Many homes still have a conventional meter. Source: Bundesnetzagentur, metering.
• In Wallonia, the grid operator is rolling out communicating meters gradually, and many homes do not have one yet.

For these employees, any reimbursement method based on the home's smart meter falls apart. A method that starts from the car works everywhere.

The 3 ways to measure home charging

A sub-meter or smart charger measures at its own output. Manufacturer apps count the energy that reaches the battery and ignore charging losses. Neither knows the real price the employee pays. To compare hardware options, see our article on smart home chargers for company car drivers and our comparison of smart charging cables.

What is a MID meter?

MID stands for the European Measuring Instruments Directive (2014/32/EU). A MID-certified meter is approved for billing: its accuracy has been tested, and its readings can be used as the basis of an invoice. The grid operator's home meter meets these requirements.

A MID meter in a wallbox or a sub-board is accurate, but it only measures what flows through it. It does not know whether the company car, a second car or a neighbour is charging, and someone has to read it or keep it connected. A cable with a built-in meter is usually not MID-certified.

What charging losses amount to

Energy is lost between the home meter and the battery: in the car's on-board charger, in the cable and through battery cooling or heating. Depending on power and temperature, that is roughly 5 to 15 %. Reimbursing only the energy stored in the battery leaves those losses unpaid, although they appear on the employee's bill. At 2,700 kWh a year and 10 % losses, that is about 270 kWh, roughly €50 per car at the Luxembourg night price.

Is a separate meter for the wallbox worth it?

A second grid operator meter just for the wallbox gives a clean, official measurement. For a company car, it is still rarely the best choice:

• it requires work on the meter cabinet and a request to the grid operator;
• it brings a second fixed network fee based on reference power, month after month;
• it does not separate the company car from a private second car charging on the same wallbox;
• the investment is lost if the employee moves, changes car or leaves.

It makes more sense in apartment buildings with shared charging infrastructure, where one meter for all charging points splits costs between co-owners.

Solar panels: what the meter does not see

If the household has solar panels, Smarty only sees what is drawn from or fed into the grid. When the car charges at midday on solar power, the session barely shows on the meter. That kWh is not free: it is not fed in and paid for. A fair reimbursement therefore needs a measurement at the car and a clear rule in the car policy on the price of self-generated power. Luxembourg subsidises private solar through the Klimabonus Wunnen programme, extended to 2030.

Why connected boxes lose sessions

A smart charger or cable has to send its data over Wi-Fi or mobile network. In practice, sessions get lost:

• underground car park or concrete garage with no signal;
• Wi-Fi changed or router restarted, the charger goes offline without anyone noticing;
• firmware update that breaks the link with the platform;
• cable lent or swapped between two cars.

Each lost session is a reimbursement to rebuild by hand. A measurement taken from the car's data does not depend on the garage's connection.

How to justify a reimbursement without a dedicated meter

Luxembourg has no official flat rate per kWh and no specific text on home charging of company cars. In practice, on the reading of the Grand-Ducal Regulation of 23 December 2016 shared by many practitioners, a company car's electricity is a running cost covered by the flat-rate benefit in kind, provided the real cost of the kWh actually charged is reimbursed. An unjustified lump sum or an amount above real cost may be treated as salary. Have your approach confirmed by your fiduciary.

Source: Grand-Ducal Regulation of 23 December 2016, coordinated text.

Measure, do not estimate

An estimate from the odometer and the official consumption looks convenient but misses reality: consumption rises sharply in winter, motorway driving costs more than city driving, and the share of public charging varies from month to month. An estimated reimbursement is therefore almost always too high or too low, and both are a problem: too high is salary, too low is a dispute with the driver.

The records to keep

• the list of home charging sessions, with date, duration and kWh;
• the employee's electricity contract or a recent bill, for the price per kWh;
• the monthly calculation: kWh at the meter multiplied by the real price;
• the written rule in the car policy.

A dedicated meter is not required. What counts is a reliable, traceable measurement. Voltaback relies on the home's MID-certified meter, not on a standalone cable meter. The method has been audited by an independent third party, with a relative error of 1.22 %. For the paperwork itself, see our article on expense claims for EV charging.

Worked example: a resident and a cross-border worker

Two employees each drive 15,000 km a year in the same car at 18 kWh per 100 km, about 3,000 kWh at the home meter, losses included.

With a single Luxembourg price, the cross-border worker loses about 390 € a year. With a measurement taken from the car and their own tariff, each is reimbursed what they actually pay, smart meter or not.

What the car policy should say about measurement

• Which charging is reimbursed: only the kWh charged at home into the company car, not household consumption.
• How it is measured: vehicle data, wallbox meter or separate meter, with priority to a method that works for every driver.
• Which price applies: the driver's contract price; with dual-rate or dynamic tariffs, the price at the time of charging; with solar panels, a set rule.
• What happens with gaps: who reports a change of contract, how missing data is filled in.
• Which data the company sees: kWh and amounts, no load curves and no locations.

How Voltaback measures and reimburses, with or without Smarty

1. Connect the car: the driver links the car in a few minutes; data comes from the manufacturer.
2. Recognise home charging: each session at home is identified, charging losses included.
3. Apply the real tariff: the price of the employee's contract, in Luxembourg, Belgium, Germany or France.
4. Reimburse monthly: a monthly export ready to import into your payroll software.

The company never receives drivers' geolocation. The platform has been ISO 27001 certified since 2 December 2025 and is GDPR compliant. The whole set-up is described on our home charging reimbursement page, and the comparison with an employer-provided charger on our alternative to a home charger page.

Reimburse the whole fleet at real cost, Smarty or not

Whether your employees live in Luxembourg City, Arlon or Trier, Voltaback measures every home charging session and reimburses it at the real tariff of their contract, with no smart charger and no box. Box-free telematics and the Electra card complete the offer. Book a demo to see the calculation on your own fleet.