Yes — but only the large one.
A homeowner faced three investment decisions at once: expand the battery, add a heat pump, install a separate heat pump meter. Three quotations were on the table — and none of them answered whether the whole thing pays off. You can request the full report below.
Client: Sorin Bals · Rhine-Main region, Germany · Published with his consent; system and quotation data anonymised
“As an entrepreneur I dislike making decisions from the gut. The EYENOD Audit was my decisive filter here: it kept me from rushing into a battery expansion and gave me instead a clear price threshold against which I can measure any quotation. It revealed the real potential in the tariff structure and provided the perfect basis for constructive cooperation with the installer.”
Translated from German. The original wording is on the German page.
The PV system was working exactly as it should. What was missing was the answer to what happens to it once a heat pump and two electric cars are added. In this case self-sufficiency falls from 53.5 % to 32.9 % — and that is where every sensible measure has to start.
15.3 kWp of PV, a 12.6 kWh battery, commissioned 07/2025. One full operating year measured in daily values.
Battery expansion of 10–12 kWh, retrofit of an air-to-water heat pump, separate heat pump meter.
From April to September, 6,854 kWh went to the grid for €480. The same kilowatt-hours in the car would have been worth €2,056.
The cheaper heat pump tariff pays off — that much was quickly calculated. What appeared in none of the quotations: in the standard configuration the heat pump then sits on its own metering point and draws grid electricity only. Cheaper tariff yes, own solar power no. Only cascade metering combines both — and it has to be requested from the grid operator before the meter is ordered.
Ask first, then order. Registration under § 14a EnWG is due before commissioning anyway — so the decision is made at the latest when the contract is signed.
Every finding ends in exactly one of four actions — with a figure, the effort involved and a page reference to the evidence. The decision itself stays with the client.
€182 a year without a single additional investment. The cheapest measure in the entire project — a setting in the controller.
The monitoring portal held one fifth of the actual system. Every target-versus-actual comparison ran against the wrong value — a genuine shortfall would never have shown up.
Three questions in one email to the grid operator — before the meter is ordered. Costs nothing and decides €142 a year.
A single module yields €96 to €110 a year and carries the installation surcharge on its own. Either the full expansion in one go — or none at all.
Instead of a recommendation to buy, a rule of thumb: quoted price divided by added capacity. Below roughly €400 per kilowatt-hour the expansion pays off — above it, not. That lets any future quotation be judged in thirty seconds, entirely without us.
The installer is explicitly cleared. The measured year came in 10 % above forecast — what looked like overperformance was pure weather. Adjusted for weather, the forecast hit the expected value and was even slightly on the safe side. That belongs in an independent report just as much as a finding does.
Every figure carries its origin. Measured for everything from the real load profile, per standard for values derived from norms and reference tables, scenario for assumptions without a solid source. The vehicles’ charging demand is a scenario — and is labelled as one.
No price forecast, but tipping points. Instead of assuming a rate of electricity price growth, the report states for each measure the annual increase at which it starts to pay off. Readers apply their own expectation — the result stays verifiable even for someone who does not share it.
I will send you either version on request — one email, no form, no obligation. The two-page summary is complete in itself: it carries the verdict and all eleven recommendations. Everything beyond it is evidence. Both documents are in German.
Two pages: the verdict, the key figures and all eleven recommendations in one table. Five minutes to read.
36 pages: seven modules, a delta report against the suppliers’ figures, the register of assumptions, standards and sources. Every recommendation with a page reference.
Shared with the client’s consent. System, quotation and equipment data are anonymised; methodology, calculations and results are unchanged. The report is a basis for decision-making ahead of an investment and gives recommendations only — it does not replace detailed engineering. The decision itself stays with the client.
Send me your quotations and your yield data — you get an independent verdict with a clear recommendation.
