The Molleaumètre is a connected water meter fitted to every shower in the hotel. It displays the litres used during the shower and cuts hot water use by 23% per shower on average, measured across 3,140 showers. The Molleau team installs it in a few minutes per room, with no building work and no change to guest comfort.
For guests, the cost of water is invisible: they see neither the litres used nor the energy needed to heat them. In a hotel, showers run longer, and the bill is very real.
Fewer litres→Less energy→Lower costs
* Assumptions: 150 L of domestic water per occupied night, water and sewerage at €4.69/m³ (French national average, SISPEA 2025), heating from 15 °C to 41 °C (around 0.030 kWh/L) at an electricity price of €0.1940/kWh (French regulated tariff, June 2026). For context: 240 to 323 L across all uses depending on the segment (French DGE, 2024). Every parameter can be adjusted in the calculator.
The Molleaumètre is a connected water meter that screws onto the mixer tap or the shower head. No aerator, no restrictor: comfort stays exactly the same, only behaviour changes.
Room by room, onto the mixer tap or the shower head, with no tools and no water shut-off. The rollout follows the housekeeping or maintenance rounds, so no room is taken out of service.
Green, amber, red: guests see their consumption in real time during the shower. A behavioural boost, with no guilt-inducing message and nothing imposed.
Data is sent automatically (self-powered by micro-turbine, battery-free). Consumption by room, changes over time, euros and CO₂, and exports ready for your audits. What a good dashboard should show →
The Molleau team fits the meters in your rooms. No plumbing work and no room taken out of service.
We review the number of rooms and how the showers are set up, then send you a quote.
The meter screws onto the mixer tap or the shower hose, in a few minutes per room, with no water shut-off.
Data flows to the dashboard. The meter is self-powered by a micro-turbine, with no battery to replace, and comes with a 2-year warranty.
Data from every shower is sent automatically over a Wi-Fi connection.
Consumption for each room, so you can spot differences and compare periods.
Savings converted into euros and CO₂, ready for your reports and certification work.
A challenges page, which you can switch on if you wish, to engage guests around water-saving habits.
The price depends on the number of rooms equipped and is quoted on request. On the savings side, here is the projection for a 40-room hotel, calculated with the same constants as the calculator and the rate measured in the Hénéo pilot: 23% less hot water per shower.
| Per year | Projection · −23% hot water per shower |
|---|---|
| Hot water saved | 285 m³23 L per night |
| Savings (water + heating) | ≈ €3,100 *€0.25 per night |
| CO₂ avoided | ≈ 1.8 t≈ 9,200 kWh of heating avoided |
* Indicative estimate calculated with the assumptions used in the Molleau calculator: water and sewerage at €4.69/m³ (French national average, SISPEA 2025), heating from 15 °C to 41 °C (around 0.030 kWh/L), electricity at €0.1940/kWh (French regulated tariff, June 2026), CO₂ at roughly 0.06 kg/kWh (French electricity mix) plus 0.30 kg/m³ (water treatment and distribution). Your property is different? Adjust every parameter in the calculator. Method: 0.0321 kWh per litre of hot water (38 °C from 15 °C, network losses 1.2), heat network emission factor 0.183 kgCO₂/kWh, water and sewerage 0.35 kgCO₂/m³, ADEME Base Carbone 2025. Water and sewerage €4.69/m³ (SISPEA 2025), electricity €0.1940/kWh (French regulated tariff, June 2026).
The dashboard identifies the lowest consumption room by room. You can then recognise those guests: a complimentary coffee at the bar, a drink at reception, a small gesture at breakfast. At minimal cost, you bring people into your food and drink areas and turn restraint into a positive part of the guest experience.
The principle is always reward, never penalty: frugal guests are recognised and no individual consumption is ever displayed. Only room-by-room measurement makes this possible, and no aerator or flow restrictor can do it.
The Hénéo pilot (RIVP group) measured every shower over several months, in two phases: first silently, to establish the baseline, then with the light ring switched on. Same shower, same occupants: only the visibility changed.
The result: 23% less hot water per shower and 15.5% less on the building's main meter, with reductions of up to 61% observed among the heaviest users. Read the full protocol and results →
Water management is a central criterion in sustainable tourism labels and regulatory obligations. The Molleaumètre supplies both the measurement and the evidence.
Green Key, Green Globe and equivalent standards require water consumption monitoring and measurable reduction measures. The dashboard documents both, room by room.
The Éco Énergie Tertiaire scheme requires consumption reductions in French buildings over 1,000 m². Cutting hot water use acts on two fronts at once: the water itself and the energy that heats it.
Savings converted into euros and tonnes of CO₂, period-by-period trends, and exports ready to drop into your non-financial reports and tender responses.
Something else on your mind? Write to us, we reply within 48 hours.
According to the 2024 study by the French Directorate General for Enterprise on water management in tourism, a hotel uses 240 L of water per person per night in the one to three star segment and 323 L in four and five star hotels, across all uses. For the water used by the guest in the room, we apply a conservative assumption of 150 litres per night, of which at least 100 L for the shower. Crucially, this is heated water: every litre avoided saves the water and around 0.03 kWh of heating energy. For the full benchmarks, read How much water does a hotel room use per night?
By making consumption visible rather than restricting the flow. The Molleaumètre's light ring naturally guides behaviour during the shower. Unlike aerators and restrictors, pressure and flow are unchanged: guests do not feel the difference, they see it. See also our comparison of shower water-saving devices.
Using Molleau assumptions of 25% average savings and 40% for the heaviest users, a 40-room hotel at 85% occupancy saves 285 m³ of hot water, roughly €3,100 and 1.8 t of CO₂ a year. The calculator recalculates everything with your own figures.
No. Each Molleaumètre screws onto the mixer tap or the shower head in a few minutes, with no tools and no water shut-off. The rollout follows the housekeeping or maintenance rounds, room by room.
Yes. Data is sent automatically to your dashboard: tracking by room, trends over time, conversion into euros and CO₂, and exports ready for audits. Enough to document the water criteria of sustainable tourism labels and to feed your Éco Énergie Tertiaire and CSRD obligations.
Hot water combines the cost of the water itself with the cost of the energy. With savings of around a quarter, the equipment generally pays for itself in under two years across a significant number of showers.
Our published results come from a sensor-measured pilot in a residence (Hénéo, RIVP group): 23% less hot water per shower across 3,140 showers. The protocol transfers directly to hotels, where use per shower is higher. Since it is the heaviest users who cut back the most, up to 61% observed, the savings expected in hotels are greater. We are currently opening our first hotel pilots. Get in touch to take part.
The price depends on the number of rooms equipped and is quoted on request. To estimate the expected savings, the online calculator works out the water, money and CO₂ saved from your own figures.
No. Flow and pressure stay exactly the same. Guests simply see their consumption during the shower, with no cut-off and no limit.
Nothing in particular. The meter is self-powered by a micro-turbine, so there is no battery to replace. It is fitted by the Molleau team and comes with a 2-year warranty.
Has your water bill gone up and you are not sure where to start? Read High water bill at your hotel: what to do?
Thirty minutes to estimate the savings potential of your property and see whether Molleau fits your situation.