An independent specification and grant navigation service for homeowners considering a chauffe-eau thermodynamique (CET). We assess your property, compare available systems for your specific installation conditions, and produce the technical documentation needed to apply for MaPrimeRénov' — without any manufacturer affiliation.
A chauffe-eau thermodynamique works on the same principle as a heat pump but is dedicated entirely to producing domestic hot water. Instead of using electrical resistance to heat water directly, it extracts heat from the ambient air in the utility room, garage, or plant room — and concentrates that heat into the water tank. The result is hot water produced at a third to a quarter of the electrical cost of a conventional immersion heater.
For the typical Dordogne household replacing an electric tank, the annual saving runs from €300 to over €800 depending on current tariff, occupancy, and how hard the existing system works. At those savings, payback after the MaPrimeRénov' grant is typically four to seven years — and the system lasts fifteen to twenty.
The assessment is not about a software calculation. It is about understanding your specific property: the installation space and its ambient temperature through the year, the existing hot water pattern, your current tariff, and which available systems suit that combination best. That judgement — independent of any manufacturer — is what the assessment delivers.
Most CET sales go through installers who supply one or two brands. The recommendation you receive reflects what they stock, not what suits your installation. An independent assessment compares available French-market systems — Atlantic, Ariston, Daikin, Thermor, Viessmann — against your specific installation conditions without any manufacturer relationship.
Unlike MVHR (which requires coupling with insulation from January 2026), a CET qualifies for MaPrimeRénov' as a single action. You can apply without doing any other works. This makes it one of the most accessible grants in the 2026 framework — particularly relevant for second-home owners who may not qualify for the wider renovation grants.
A CET with a timer or smart relay scheduled to heat water during solar production hours is one of the most effective ways to increase self-consumption from a PV system — more effective per pound than battery storage in many profiles. The assessment considers this interaction if solar is in scope.
There is no CET-specific sizing tool in the assessor toolkit yet. The assessment is a professional judgement document: a written specification based on a structured evaluation of your property, installation space, occupancy pattern, and energy use. That independence from any tool or manufacturer is the point.
A note on tooling: The MVHR Sizing Audit uses MVHRCalc to generate a compliance-checked airflow schedule. The CET assessment does not yet have an equivalent tool — it is a structured professional specification based on site conditions and assessor judgement. A dedicated CET sizing tool is in development for a future release. The assessment is no less rigorous for the absence of software; for a system of this type, professional judgement is the appropriate basis.
The Energy Independent · Dordogne
Independent · No manufacturer affiliation
Adjust the inputs to match your household. The calculator estimates annual savings, grant impact, and indicative payback based on 2026 EDF tariffs and typical CET performance figures for Dordogne (H1c climate zone).
Four steps. Fixed-price. Report delivered within five working days of the assessment visit or document review.
Short no-charge conversation to confirm the assessment is appropriate and understand your property, tariff, and renovation context.
On-site for Dordogne clients: installation space measured, ambient conditions assessed. Desktop: photographs and questionnaire.
Hot water demand modelled against current costs. Three systems compared independently. Tank size, COP, and scheduling recommendations set.
Written specification with manufacturer comparison, MaPrimeRénov' dossier, and RGE installer brief. Delivered within five working days.
No, but it matters how cold it gets. A CET extracts heat from ambient air — the colder that air, the harder the system works and the lower the COP. In a garage that drops to 5°C in January, the system is still viable but less efficient than one installed in a utility room that stays at 12–15°C. The assessment measures or estimates your ambient temperature range through the year and factors this into the system recommendation and savings estimate.
Yes, and the combined assessment is priced at a reduced rate. In some configurations — particularly where the MVHR extract passes through the utility room — the two systems can be integrated. Whether that is technically appropriate for your property is assessed as part of the combined scope. Both are separately eligible for MaPrimeRénov' grants.
A monobloc unit houses the heat pump and tank together in one cabinet, typically installed in the utility room. A split unit separates the heat pump (outside or in a less-accessible space) from the tank. Monobloc units are simpler to install and better suited to most French rural properties. Split units are relevant where installation space is constrained or where the heat pump needs to be separated from living areas for acoustic reasons. The specification recommends the appropriate type for your installation.
Yes. Separating domestic hot water production from the heating boiler is a standard upgrade path. A dedicated CET produces hot water independently of the boiler, typically at significantly lower cost. The assessment calculates the saving against your actual gas cost and considers whether a separate unvented cylinder is needed to work alongside your existing heating system.
Yes, with one important grant caveat. MaPrimeRénov' is only available for a principal residence — second homes and rental properties are not eligible for the main grant. However, TVA at 5.5% still applies on qualifying works, and the energy saving case stands regardless of grant eligibility. The assessment confirms your eligibility position clearly and calculates payback with and without the grant.
A straightforward CET installation by an RGE contractor typically takes one day. More complex installations — where a new electrical supply is needed, the existing cylinder location is difficult to access, or plumbing modifications are required — may take two days. The assessment flags any installation complexity issues and notes them in the installer brief so contractors can price accurately.
The first conversation is no-charge and without commitment. It takes fifteen minutes to establish whether a CET is the right move for your property and what grant you would be entitled to.