Price of a
thermodynamic water heater.

We went through every “water heater” and “hot water tank” line in our quotes drawn up between 2024 and 2026. Five projects include a thermodynamic water heater, about fifteen an electric tank. The amounts are rounded and excluding tax: they are benchmarks, not a price list, and each home is priced after a visit.

All the thermodynamic water heaters in our quotes are 240-litre floor-standing models, the capacity we choose for a family house. Electric tanks range from 100 litres in an apartment to 200 litres in a house. Source: survey of our 2024-2026 quotes in Savoie and Haute-Savoie.

On the five projects where we specified a thermodynamic water heater, it came with other equipment: a heat pump, mechanical ventilation, sometimes a whole heating network. The labour there is counted in a shared lump sum, from €3,000 to €5,000 excl. VAT for the whole. We therefore cannot honestly isolate the price of fitting alone, and we prefer to say so rather than invent a line.

What a fitting includes, on the other hand, is known:

• removal of the old tank, draining it and taking it away;
• the cold and hot water connections, with a new safety unit and its discharge to a trap;
• the condensate drain, which the electric tank does not produce;
• a dedicated electrical line, which our electricians run from the panel when it is missing;
• the air ducts and their wall penetrations, if the unit takes air from outside rather than from the room.

On our projects, this work is carried out by our own salaried plumber-heating engineers and electricians, each in their own trade: a single quote, a single team responsible for the result.

At purchase, the gap is clear: about four times the price of an electric tank of similar capacity. A standard tank heats the water with a heating element; the thermodynamic water heater does the same job with a small heat pump that captures heat from the air, and keeps the element only as back-up. It therefore uses markedly less electricity for the same amount of hot water.

How long does it take to recover the difference? That depends on three things that we look at on site rather than promise a figure: the number of people in the household, the temperature of the air the unit draws from, and its efficiency as declared by the manufacturer. For a couple in a small apartment, a well-sized electric tank often remains the reasonable choice. For a family in a house, with a garage or storeroom, the thermodynamic model has its full place.

One last case deserves raising before buying anything: if you are also changing your heating, a so-called dual-service air-to-water heat pump already produces hot water. On two of our 2026 quotes, replacing a gas boiler and the electric tank with a single heat pump came to €14,400 and €16,200 excl. VAT. The detail is in our guide to air-to-water heat pump prices, and the overall choice in our guide to replacing an oil boiler.

A thermodynamic water heater working on room air needs an unheated room that is large enough: garage, storeroom, cellar, utility room. It takes heat there and discharges cooler air. In a room that is too small, or too cold, the heat pump delivers less and the back-up element takes over more often.

This is the point to watch in Savoie and Haute-Savoie. A buried basement keeps a fairly stable temperature in winter; an attached, poorly closed garage in a ski resort drops much lower. When no room is suitable, the solution is to duct the unit to the outside, at the cost of two wall penetrations, or to go back to an electric tank.

In an apartment, the question arises differently: a bathroom cupboard is not enough for a room-air model, and piercing a facade in a co-owned building requires the agreement of the general meeting. We check these constraints before pricing.

VAT at 5.5% applies to the supply and fitting of a thermodynamic water heater in a home completed more than two years ago, provided the unit reaches the minimum efficiency set by Article 30-0 D ter of Annex IV to the French General Tax Code (code général des impôts): 95% for a draw-off profile M, 100% for L, 110% for XL and above. A standard electric tank, for its part, falls under the 10% rate. The full rules are in our guide to VAT on renovation work.

The CEE premium remains open: operation sheet BAR-TH-148 “thermodynamic storage water heater” awards 14,700 kWh cumac in a detached house and 11,800 in an apartment. The premium in euros is paid by an energy supplier and varies from one to another; it cannot be combined with the sheet for an air-to-water heat pump.

MaPrimeRénov' per measure no longer funds it: since 1 September 2026, the order of 25 August 2026 has abolished this flat rate for heat pumps dedicated to domestic hot water. The thermodynamic water heater remains fundable within a major renovation, which requires at least two insulation measures. The full picture is in our MaPrimeRénov' 2026 guide.

These grants require a professional holding the corresponding quality label. Our RGE CertiRénov certification (no. CR-2026-73-0095) covers the overall renovation offer; for a water heater replacement on its own, we check with you, before signing, what is eligible.