The end of saldering — net metering — is the largest single change in Dutch residential energy in a decade. The headline is widely understood: from January 2027, the kWh you export will no longer cancel one-for-one against the kWh you import. The consequences are less widely understood. This piece is a worked example for a typical household — a 4.5 kWp roof, four panels facing south, two facing east — and a walk through what changes, and what does not.
The system, as it stands today
A 4.5 kWp installation on a Dutch roof produces, in a representative year, around 3,950 kWh. A household with that system and an annual import need of 3,400 kWh sees, on the bill, the following arithmetic:
- Imported from grid: 3,400 kWh
- Exported to grid: 2,300 kWh
- Self-consumed at the moment of generation: 1,650 kWh
- Net billed (under saldering): 3,400 − 2,300 = 1,100 kWh
At a contract rate of €0.30/kWh — a reasonable 2026 fixed tariff — the import bill is €330 per year for energy, before fixed charges. The household effectively earns €0.30 for every exported kWh, because each one cancels one imported kWh at the same price. The system pays back in around eight years and is, financially speaking, a savings account that compounds tax-free.
The system, after 2027
From January 2027, the cancellation rule disappears. Each exported kWh is now compensated at the supplier's feed-in tariff — a number the supplier publishes, typically between €0.04 and €0.08/kWh in the dynamic market and €0.06 to €0.10 on fixed contracts. Some suppliers additionally levy a terugleverkosten — a feed-in charge — on customers whose annual export exceeds their import. Same household, same panels, same year of weather:
- Imported from grid: 3,400 kWh at €0.30 = €1,020
- Exported to grid: 2,300 kWh at €0.07 (representative feed-in) = €161 credit
- Net energy bill: €859
The increase against the saldering baseline is €529 per year. The system still saves money against the no-solar counterfactual (which would be 5,050 kWh imported at €0.30 = €1,515). The new saving is €656 per year, against €1,185 under saldering. The payback period extends from eight years to roughly thirteen.
Where the lever moves
The new arithmetic rewards self-consumption — kilowatt-hours used at the moment they are generated — far more than it rewards generation itself. Under saldering, a kWh exported and a kWh self-consumed are economically identical; both save €0.30. After saldering, the exported kWh saves €0.07 and the self-consumed kWh saves €0.30, a 4.3-fold gap. Everything in residential solar economics, post-2027, follows from that ratio.
For our 4.5 kWp household, the self-consumption fraction today is 1,650 / 3,950 = 42 per cent. Three habits, none of which require new hardware, can raise it:
- Move the dishwasher to noon. A 1.5 kWh cycle, run between 12:00 and 14:00 instead of after dinner, shifts 1.5 kWh of self-consumption per cycle. Over a year, that is roughly 400 kWh.
- Run the EV charger during peak generation. A 2.4 kW (10A) charge between 11:00 and 15:00 captures 9.6 kWh of solar that would otherwise have been exported. If the household drives 12,000 km/year, that habit alone moves 1,200–1,500 kWh from export to self-consumption.
- Set the heat pump to pre-heat at noon in shoulder seasons. A house with reasonable insulation will hold the temperature into the evening at a fraction of the import cost.
None of these requires a battery. All three move the self-consumption fraction from 42 per cent toward 55 to 60 per cent. The €529/year penalty above shrinks to closer to €280.
Where a battery changes the maths
A 5 kWh home battery, cycled once per day on average, shifts roughly 1,500 kWh per year from export to self-consumption — closing nearly the whole gap. Whether the maths works depends, as always, on the spread between the import price (what each shifted kWh saves) and the feed-in tariff (what it would otherwise have earned). A spread of €0.23/kWh and 1,500 kWh shifted is €345/year in additional savings — enough to bring battery payback to roughly nine years on a system that costs €3,000 to €4,000 today. We have a separate piece on the battery worksheet that walks the spread calculation in detail.
What this is not
It is not a reason to delay solar. The 2027-onwards household with no panels imports 5,050 kWh per year at €0.30 — a €1,515 bill, before any future tariff increase. The household with 4.5 kWp pays €859. The savings have shrunk, the payback has stretched, but the sign on the bottom line has not changed.
It is also not a reason to oversize a new installation. Pre-2027, an 8 kWp roof made sense because every excess kWh was monetised one-for-one. Post-2027, every excess kWh is monetised at one-quarter of its old value. The right sizing for a new system is the one that approximately matches your annual consumption — not the one that maxes out the roof.
What the wizard does with this
The comparator above runs your household's actual or projected hourly consumption shape against each supplier's 2026 tariffs and their published 2027 feed-in policies. The output is not a single number; it is the same household's expected bill under each tariff after the rule change. That, more than any general rule, is the figure on which the new solar decision should turn.
