In condominium ownership, the roof belongs to the community – a solar system therefore needs a resolution from the condominium owners' assembly. Which majority is necessary depends on the legal classification of the measure and on the regulations. Successful projects are rarely decided by the technology, but by the preparation: clean variants, clear cost distribution according to value quotas and a well-thought-out model for electricity distribution – mostly ZEV or vZEV. (As of: July 2026)
Key points in brief
- The roof is a communal part – no condominium owner can build a system on it alone.
- An assembly resolution is required; the required majority depends on the classification and regulations.
- Costs and revenues usually follow the value quotas – or a specially resolved regulation.
- For the distribution of electricity to the parties, the vZEV is often the door opener: no measurement modification, low entry barrier.
- Incentives exist as for any roof – one-off feed-in incentive of the federal government, in the City of Zurich additionally the municipal contribution since August 2026; the community submits the application.
- The renewal fund can bear the financing – if the resolution provides for it.
Who owns the roof – and who decides?
The starting point in condominium ownership is always the same: you own your apartment under exclusive rights – but the roof, facade and building envelope are communal parts. No one can build a solar system alone on the shared roof, not even «only above their own apartment». The path necessarily leads through the community: an agenda item, a discussion, a resolution by the assembly.
Which majority is required is the core legal question – and it depends on how the measure is classified. The law grades structural measures according to their nature (from necessary to useful to luxurious), with different quorums; in addition, the regulations of one's own community may contain their own rules. A solar system is regularly discussed as a useful measure here – but the specific classification and the required majority must be clarified individually for each community, ideally with the administration and, in case of doubt, with legal assistance. Do not rely on blanket statements from the internet – not even on this one: the classification is a case-by-case matter.
More important for practice than the theory of quorums is the experience: Well-prepared projects find their majority. The modules are rarely controversial – what is controversial are unresolved questions of cost and benefit.
How are costs, revenues and electricity distributed?
Three distribution questions that must be answered before the assembly – not after:
The costs
Communal investments basically follow the value quotas, unless regulations or the resolution provide otherwise. An attractive source of financing is the renewal fund – the system is an investment in the communal building envelope, and where the fund is well-endowed, the project can be managed without additional contributions. Whether the fund may and should be used for this is part of the resolution.
The revenues
Feed-in tariff and electricity revenues flow to the community and are distributed according to the same key as the costs – the logic corresponds to what the article on ZEV surplus remuneration describes: whoever invests receives the revenues; cleanly regulated in the agreement before the system is running.
The electricity: ZEV or vZEV in condominium ownership
So that the parties can use the solar electricity directly, a distribution model is needed – in a multi-party building, this is called ZEV or vZEV. For condominium owners' communities, the vZEV is often the door opener: it does not need a measurement modification, i.e. no structural intervention that would have to be co-resolved – the grid operator bills virtually. This noticeably lowers the entry barrier of the assembly; the vZEV article explains the details. If a shared battery storage is added later, the considerations from the article battery storage in the apartment building apply.
| Distribution question | Principle | Where regulated |
|---|---|---|
| Investment costs | according to value quotas (or resolution) | Regulations + resolution |
| Revenues (feed-in) | analogous to cost distribution | ZEV/usage agreement |
| Electricity to the parties | ZEV or vZEV | Model choice + agreement |
| Financing | Renewal fund or levy | Resolution |
Orientation, As of: July 2026 – no legal advice. The law, your regulations and the resolutions of your community are authoritative.
What incentives are there for a STWEG system?
The same incentive sources apply to a communal system as to any other roof – with one difference: the applications run via the community, in practice via the administration, and therefore belong in the resolution. The contribution flows to the community and reduces the jointly borne investment.
- One-off feed-in incentive of the federal government: Systems under 100 kWp fall under the KLEIV. The capacity contribution is around CHF 360 per kWp up to 30 kWp and around CHF 300 per kWp for the system part above that (on-roof; in-roof around CHF 400 per kWp), in each case plus the base contribution; the application is submitted via Pronovo after commissioning. Details: One-off feed-in incentive and KLEIV or GREIV?.
- City of Zurich: Since 1 August 2026, a base contribution of CHF 5,000 applies plus CHF 450 per kWp up to 30 kWp (staggered lower above that), plus a CHF 3,000 flat rate for systems requiring a permit – and for the first time a contribution towards battery storage (CHF 1,000 plus CHF 100 per kWh). Details: City of Zurich incentives and City of Zurich battery storage incentives.
- Canton and municipality: The Canton of Zurich does not pay any blanket PV incentives – nor do Aargau, Thurgau, Schaffhausen and Schwyz; individual municipalities add something, which can be checked precisely by address via the municipal incentives guide. The city of Zug incentivises roof systems analogous to the one-off feed-in incentive (maximum CHF 5,000) and battery storage from 6 kWh with 20 percent of the costs.
Guideline values, As of: August 2026 – the rates are adjusted annually; the current publications from Pronovo, city and canton are binding.
How does the project get through the assembly?
With preparation worthy of the name – the always identical success factors from practice:
1. Inform early instead of taking by surprise. A project that appears for the first time as a proposed resolution arouses resistance. Better: an information round before the assembly – pick up on interests, collect questions, take sceptics seriously. 2. Variants instead of all-or-nothing. A small and a full layout, with and without a distribution model, each with costs per party according to value quota. Those who can choose are more likely to agree. 3. Answer the money question per party. Not «the system costs X», but «for your 82/1000 value quota this means Y, financed from the fund» – this is the figure every owner wants to know. 4. Administration and numbers dossier. An administration that understands and supports the project, plus a quote that withstands assembly questions: yield forecast, maintenance, responsibilities, model comparison ZEV/vZEV. 5. Formulate the resolution cleanly. What exactly is being resolved – system, financing, distribution model, agreement? A precise motion prevents the assembly from failing over formal questions.
That the effort is worth it is shown by the counter-calculation: the shared roof is often large, the shared consumption is high due to the mix of households – condominium ownership properties are often economically better solar locations than single-family homes. The hurdle is not the technology and not the money – it is the path to the resolution. And that can be planned.
Which provider is right for a solar system in condominium ownership?
In a single-family home, a provider has to convince one person. In condominium ownership, they convince a whole assembly – and the administration that looks after the project afterwards. That is why other points than the price per module count in the choice:
- Assembly-ready documents: Variants with costs per value quota, a proposal for financing and a draft for the proposed resolution – prepared in such a way that the administration can put the matter on the agenda.
- Experience with ZEV and vZEV: Measurement concept, clarification with the grid operator and the subsequent billing among the parties. Ask whether the provider has already implemented a distribution model and not just planned one.
- Electrical installation in the multi-party building: Connection to the existing meter distribution, if necessary modification of the measurement. For this, the executing company needs an ESTI installation authorisation (Art. 14 NIV) – verifiable in the public register.
- A contact person beyond the construction: Who is responsible for faults, monitoring and questions from the administration after commissioning? In communal systems, unresolved responsibility is the most common weak point.
- References in condominium ownership: A system on a single-family home says little about whether a provider can accompany a resolution process. Ask them to name a comparable communal system.
From our projects in the Zurich region: In Fällanden, we realised two systems in condominium ownership in 2023 and 2024 – 74.5 kWp at Sagiwäg and 36.5 kWp at Toktergasse, both with ZEV and self-consumption optimisation (more on this: Solar system in Fällanden). In Uitikon, a 26.9 kWp system with bifacial modules went into operation in 2026 on the flat roof of an apartment building belonging to a co-ownership community. Key data and pictures are available under Projects. As an executing specialist company, we take over planning, installation and electrical connection ourselves; the page Photovoltaics for apartment buildings and businesses describes how we accompany apartment buildings and communities.
STWEG projects almost never fail in our experience because of a no from the assembly – they fail beforehand because nobody prepares the motion properly. Our proven approach in the Zurich region: We deliver an assembly-ready dossier to the initiating party or the administration – two variants, costs per value quota, vZEV enquiry already made to the grid operator, sample resolution for formulation. At the assembly itself, we answer the technical questions so that the discussion stays on the real topics: money, distribution, responsibility. With this preparation, we have experienced assemblies that reached a unanimous resolution after twenty minutes – and that in communities that previously wanted to «talk about it sometime» for years.
Frequently asked questions
Can I, as an individual condominium owner, build a system «only for me»?
Not on the communal roof without a resolution – the roof belongs to everyone, even the part above your apartment. Special cases via an exclusive assignment of use are conceivable, but that also requires the community. The realistic way is the communal project – it is also usually the more economical one.
What majority does the solar resolution need?
That depends on the legal classification of the measure and your regulations – blanket answers are unprofessional here. Clarify the quorum with the administration before the assembly, in case of doubt with legal support, and formulate the motion accordingly. Experience shows that well-prepared projects find their majority.
Are we allowed to use the renewal fund for the solar system?
The fund serves the renewal and maintenance of the communal parts – a system on the shared roof can fall within this purpose, but its use expressly belongs in the resolution. The administration will check whether your regulations provide for anything special. Cleanly resolved, the fund is often the most elegant financing route.
What about owners who do not want to participate?
In the resolution, the majority principle applies – a resolved communal measure is borne by all according to value quota. With electricity procurement, more flexibility is possible: models like the vZEV can regulate participation without every party having to purchase solar electricity. Exactly such questions belong in the agreement.
Who operates the system afterwards?
The community – in practice delegated to the administration or a service provider, analogous to the rest of the building technology. Monitoring, billing of the distribution model and maintenance need to be assigned; the billing routes are described in the article on the ZEV in the apartment building. Unresolved responsibility is the most common operational weakness – and the most easily avoidable.
Free initial consultation
STWEG project? We deliver the assembly-ready dossier.
Variants with costs per value quota, vZEV clarification with the grid operator, sample resolution – and on request we answer the technical questions directly at your assembly. You can go through the structure of such a dossier yourself beforehand: our resolution folder for the owners' assembly is free of charge and can be filled out directly.
Want to calculate yourself first? Solar calculator with official roof data →
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Solar systems for apartment buildings, condominiums & businesses – from the specialist →
Swissolar-certified specialist company · ESTI installation authorisation (Art. 14 NIV) · in Zurich since 2017 · over 150 systems completed · a personal answer from the specialist company, no call centre
Sources: Pronovo/EnFV Annex 2.1 (One-off feed-in incentive, As of: August 2026), incentive programme of the City of Zurich (since 1.8.2026), cantonal incentive programmes 2026, ZGB (condominium ownership, structural measures), regulations and assembly practice, empirical values from STWEG projects of ecoEn GmbH, Zurich region. No legal advice – the law, your regulations and the legal assessment in the individual case are authoritative.
Last updated: 9 July 2026 · Author: ecoEn editorial team
