How much do you save on grid electricity?
Free demo · electricity cost comparison · 28-day archive
7-day charging window
Set your annual grid draw and grid connection rating — we compare electricity costs in the archive backtest: typical day-ahead-only (~48 h) planning vs. a full 7-day forecast across the week.
Battery storage
EV charging
Heat pump
PV export
Your annual grid draw & grid connection rating
Choose how much electricity you draw from the grid per year (annual consumption minus PV export). From that we estimate your typical need for the next 7 days — to time-shift battery, EV and heat pump charging.
Grid connection rating: Maximum power draw from the grid per hour — kW × 1 h = kWh. This is your fuse/main breaker limit — what your installation, EV charger, heat pump and battery may draw at once (default 11 kW). Euro savings refer to your grid draw in the 7-day window.
Added value: electricity costs — 7 days vs. day-ahead only
How we calculate this comparison — in plain language Click to expand
How savings are calculated: After signing in you will see a step-by-step breakdown of “Typical today”, “With SpotpriceAPI”, and the savings — from archived prices and selected charging hours.
Sign in — show calculationComputing live …
Evaluating your charging windows from the archive — usually just a few seconds.
What one day looks like
Which days to charge?
Did the AI spread charging across the right days? Blue = AI recommendation, green = best in hindsight.
Recommended charging hours
Hours the AI would pick for charging — plus the real exchange price in cents per kWh.
Price comparison at those hours — tap the chart on mobile or hover with the mouse.
What do the metrics mean?
- Hit rate — three levels
- We show three levels: 1) Exact hour hits — recommended slot equals one of the N cheapest in hindsight (strict). 2) Near miss — slot is in the actual top pool (2×N, max. 12). 3) Day spread — same number of charging hours per calendar day as optimal. Savings vs. day-ahead depend mainly on (2) and (3), not only exact hours.
- Savings with 7 days
- How much cheaper the 7-day forecast was in the lookback vs. day-ahead-only planning (~48 h) — using actual spot prices and your selected grid draw (kWh in 7 days) plus grid connection rating in kW. The main value shows savings in €; below that, the price advantage in ct/kWh. Positive = you save. A dash (—) means no measurable difference in the period.
- 48 h vs. 7 days
- Many systems plan with day-ahead prices only (~48 h visible). We compare: cheapest hours in that short window vs. a 7-day forecast. Costs in € for your grid draw in 7 days (adjustable) at grid connection rating in kW (1 h = kW × 1 h = kWh), billed with actual archived spot prices.
- Archive & model
- Lookback using the current model on archived inference runs (~12:00 Vienna). After a model update the archive may have been recomputed once.