In day-to-day operation, the ZEV in an apartment building stands or falls with the billing: each party pays for its metered share of solar and grid power, the internal solar price may not exceed the external standard product, and the annual statement transparently shows the solar share, grid consumption and surplus. Billing is done in-house, via the property management, or through a service provider – from around half a dozen parties upwards, the service provider is usually worth the money. (As of: July 2026)
Key points in brief
- Billing is based on actual metering per party – if you don't record the solar and grid shares properly, you create disputes instead of transparency.
- The internal solar power price is capped: never more expensive than the local utility's external standard product.
- Three billing approaches have become established: in-house, via the property management, or through a specialised service provider.
- Tenant changes are routine – the ZEV needs a standard process for this rather than case-by-case solutions.
- A transparent annual statement showing solar share, grid consumption and surplus is the best conflict prevention.
How does ZEV billing work day to day?
On the same principle as any electricity bill – except that the supplier is your own roof. For each party, how much solar power and how much grid power they've drawn is metered; both are billed at different prices. The grid share is passed on at the tariff the ZEV pays the utility, the solar share at the internally set solar price.
The basis for this is the metering within the building: for the classic ZEV, private meters (submetering); for the virtual one, the grid operator's smart meters. Who measures what and how the levels interact is explained in the article Metering, meters & monitoring. For residents, little changes day to day – they still receive an electricity bill, just from the ZEV instead of the utility, with two line items instead of one.
For the internal price, the law sets the guardrail to protect tenants: solar power from your own roof may not cost residents more than the external standard electricity product. In well-calculated associations it's noticeably lower – the owners still earn, because their generation costs are lower. The complete cash flows, including surplus remuneration, are covered in the article ZEV surplus.
Who should handle billing – yourself, property management or a service provider?
Three approaches have become established, and the right choice depends almost entirely on size:
Billing it yourself. The owners read the meters, calculate the shares and issue the invoice – realistic for small buildings with few parties and owners who enjoy working with spreadsheets. The effort is manageable, but it's recurring, and any mistake feeds directly into the relationship with tenants.
Via property management. The property management integrates the electricity billing into the service charge statement – a natural fit where professional management is already in place. It's important that the management understands the metering concept and doesn't treat the electricity item as a flat rate: the ZEV bills according to metered consumption, not floor area.
Via a service provider. Specialised providers take over metering, billing and collections for a fee. From around half a dozen parties upwards, this is usually worth the money – the effort per party falls, professionalism increases, and the owners are out of the invoicing loop.
| Route | Suits | Strength | Weakness |
|---|---|---|---|
| In-house | 2–5 parties | inexpensive, full control | effort, risk of errors |
| Property management | managed properties | single point of contact | electricity know-how needed |
| Service provider | from ~6 parties | professional, scales well | ongoing fee |
For guidance, as of: July 2026. What's decisive is the size, structure and existing management situation of the property.
What belongs in the annual statement?
Three figures that every party can follow: solar share, grid consumption and surplus. Showing these three items transparently takes the ground out from under the most common ZEV criticism from the start – «the owner is just cashing in twice». Residents see how much cheap solar power they've used and what it would have cost them compared to grid power; the owners document that the price cap has been observed.
On top of that come the formal elements of any proper statement: the price formula from the ZEV agreement, the billing period, the meter readings per party. Sounds like bookkeeping – and it is, and that's exactly the point: a ZEV whose billing looks like a proper service charge statement is perceived as normal. One whose figures nobody can trace becomes a permanent agenda item.
A proven addition is the year-on-year comparison: how high was the building's overall solar share, and how is it developing? That turns the mandatory statement into a small record of success – and at the same time gives the owners the data basis to decide on optimisations such as shared appliances or a storage system.
How does the ZEV handle tenant changes?
With a standard process – because turnover is not the exception in an apartment building, it's routine. Three things need to happen with every change: record the meter reading on the key date, prepare the final statement for the outgoing party, and add and inform the new party in the ZEV.
The last point is the one most often forgotten: new tenants need to know that they get their electricity from the ZEV and what that means for them – ideally as a short factsheet at the start of the tenancy rather than a surprise on the first statement. The entry and exit terms themselves belong in the ZEV agreement drawn up when the association is set up; in operation, this becomes routine.
For the organisation, that means: the ZEV needs a person or body responsible for these processes – the owners, the property management or a service provider. Left unregulated here is equivalent to: it will sort itself out at the first conflict.
The ZEV associations that we still find as satisfied customers years later have one thing in common: a statement that nobody needs explained. Three line items, a clear price formula, built the same way every year. The problem cases also have one thing in common – not prices that are too high, but figures nobody can trace. Our advice for every apartment-building project in the Zurich region: decide the billing question before the system goes live, and when in doubt, choose the service provider. The fee is money well spent if it means the owners never have to argue with a tenant about kilowatt-hours.
Frequently asked questions
Do tenants pay more for electricity in a ZEV?
No – the statutory price cap prevents that: internal solar power may not be more expensive than the local utility's external standard product. In well-set-up ZEV associations, residents pay less for the solar share than for grid power, without having invested themselves.
How often is billing done in a ZEV?
Annual billing with instalment payments is usual, similar to service charges – sometimes quarterly or monthly too, depending on the billing approach. More important than the frequency is traceability: meter readings, the price formula, and the three items solar share, grid consumption, surplus.
What happens if a party doesn't pay?
Then the same applies as for any claim arising from the tenancy or the agreement – reminders and, if necessary, debt collection. A service provider takes exactly this unpleasant part off the owners' hands. The ZEV cannot simply cut off the electricity of a defaulting party; the supply situation remains regulated.
Does the ZEV need its own accounting?
Traceable billing records, yes; a separate company set of accounts, usually not – the ZEV is generally not its own legal entity, but a contractual association. For larger properties, the property management or the service provider handles the accounts.
Is a ZEV worthwhile for a small apartment building too?
Often yes – precisely because many parties consume differently during the day, which makes the combined self-consumption high. For very small buildings, it's worth looking at the virtual ZEV, which reduces setup costs. The choice of model is covered in the big comparison.
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Sources: Energy Act (EnG) and Energy Ordinance (EnV) on the association for self-consumption, ElCom FAQ on the energy strategy under the Mantelerlass (as of 2026), practical experience from apartment-building projects by ecoEn GmbH, Zurich region.
Last updated: 9 July 2026 · Author: ecoEn editorial team
