Solar panels in apartment buildings: solutions, regulations, and benefits for those who are serious

Installing solar panels in apartment buildings involves placing photovoltaic systems on shared parts of the property—usually the roof—to generate electricity from sunlight. There are two main types of configurations: centralized systems and individual private systems. In both cases, the goal is to reduce reliance on the grid and improve the building’s sustainability.

In a context of rising energy costs, producing renewable energy on-site is a smart choice. Solar in apartment buildings helps cut electricity expenses for common areas and, in the case of private systems, even for individual units. It also contributes to increasing the building's energy class, positively impacting property values.

Unlike systems installed on single-family homes, shared photovoltaic systems require the coordination of multiple owners, both in terms of space and costs. This demands more structured management, especially in terms of legal and organizational aspects—but it also offers opportunities for economies of scale, access to incentives, and innovative collective energy use.

Main solar solutions for apartment buildings

Centralized solar system for shared areas

A centralized photovoltaic system is a solution shared by multiple residents who decide to install solar panels to power only the building’s common services, such as stairway lighting, elevators, automatic gates, or communal spaces. The electricity produced cannot be used by individual apartments, but it significantly reduces shared energy expenses.

Installation requires approval from the homeowners’ association by simple majority—that is, at least 50% plus one of the attendees, representing at least one-third of the ownership shares (millesimal values). Only those who vote in favor are responsible for the costs and benefit from the savings. This allows a smaller group to fund the project without forcing the others to participate.

The system can be combined with storage batteries to save excess energy for use in the evening. Surplus energy not consumed on-site can be fed back into the grid, with the possibility of financial compensation through mechanisms like "Scambio sul Posto" or "Ritiro Dedicato," both managed by the GSE (Italian Energy Services Operator).

If properly designed and managed, a centralized system can offer a fast return on investment, stable cost reductions, and improved overall energy performance for the building.

Individual solar system for private units

In addition to the shared option, individual residents can install their own private solar system, even if it’s placed on common areas like the roof. This is permitted under article 1122-bis of the Italian Civil Code, which protects the right of each owner to improve their unit’s energy efficiency.

Installation is allowed as long as it doesn't alter the intended use of common areas or compromise the building’s safety, stability, or aesthetics. In protected historic or landscape areas, special permits or notices to the local authorities (CILA or SCIA) may be required.

No vote is needed from the homeowners’ assembly, but the resident must notify the building administrator. The law thus safeguards individual rights while respecting collective rules.

This right has been reaffirmed by Italy’s Supreme Court (ruling no. 1337/2023), which confirmed that owners can install solar systems on shared spaces, provided they do not infringe on others' rights or violate current regulations.

Regulations and paperwork for shared solar systems

Documentation, permits, and notices for installation

In addition to the assembly resolution, the system must meet CEI technical standards, be connected to the grid with approval from the local utility, and in some cases, require building permits.

Systems under 20 kW typically follow a simplified procedure: activity start declaration, communication to ENEA (National Agency for Energy Efficiency), and direct access to incentives.

Use of shared spaces under civil law

Article 1102 of the Italian Civil Code states that all residents may use common areas, provided they do not prevent others from doing the same. This principle also governs the use of the roof for solar panels.

When and how to update building regulations

If the existing condominium rules don’t cover solar panel installations, it’s advisable to update them, clarifying criteria for space allocation, power limits, and technical requirements.

Costs, tax deductions, and financial incentives

How much does a shared solar system cost?

The average cost of a 7 kWp solar system for a building is around €10,000, including design, installation, and paperwork. Adding battery storage increases energy independence but also affects the overall budget.

50% tax deduction and other benefits

Installation costs are eligible for a 50% tax deduction over 10 annual installments, as part of Italy’s renovation incentives.

To access the incentive, you must:

• use traceable payment methods (e.g., bank transfers with appropriate codes),

• keep all invoices and receipts,

• submit a declaration to ENEA within 90 days of work completion,

• register the system with the GSE.
  
  

Local incentives and energy-efficiency grants

In addition to national tax breaks, many regions, municipalities, and chambers of commerce offer local grants or low-interest loans—sometimes even non-repayable—to support energy upgrades in apartment buildings. Check official websites regularly to avoid missing out.

Mandatory notifications and payment tracking

The ENEA notification must be submitted online within 90 days after the project is completed. Failure to do so can void the tax deduction. Payment traceability is also a strict requirement for claiming the benefit.

Managing rooftop access and panel space allocation

Who can install panels on the shared rooftop?

Any resident can propose a project, but it must respect the rights of others. If multiple requests arise, allocation should be based on fair criteria, such as ownership shares or equal roof surface.

Rules for using shared spaces for solar generation

Installations must be planned to allow future residents to add their own systems. A shared agreement helps prevent conflicts and promotes fairness.

Agreements between residents and conflict resolution

A written agreement—filed with the building administrator if needed—should outline usage rights and maintenance responsibilities. It can also include clauses for selling the apartment.

In case of disputes, civil mediation is recommended to avoid lengthy and costly legal proceedings.

Estimating environmental and financial benefits

GSE simulator to assess investment returns

The GSE provides an online simulator that estimates the convenience of a solar installation. By entering basic technical data, you can view annual production, self-consumption, and savings.

Every kilowatt-hour of solar energy avoids about 0.5 kg of CO₂ emissions. In a condominium, this can have a significant impact and help meet EU climate goals.

Payback time: how long before it pays for itself

The average payback period ranges from 5 to 9 years, depending on system cost, energy usage, and battery presence. Incentives can significantly speed up the return.

Centralized systems benefit from economies of scale but require coordination. Individual systems are easier to manage but may be less cost-effective on a small scale.

Shared self-consumption and energy communities

What is shared self-consumption?

It’s a model where energy produced by a shared system is distributed among multiple users based on predefined shares. It is regulated by the “Milleproroghe” decree and supported by national incentives.

Financial and organizational advantages

Residents can greatly reduce energy bills while improving the building’s energy resilience. It also encourages collaboration and trust among neighbors.

Shared system configurations

Within a building, all participants must be connected to the same transformer station.
Energy communities (CERs) allow multiple buildings to share energy locally and benefit from GSE-incentivized rates.

Management and governance of shared energy

Management can be entrusted to a third party such as an ESCo or cooperative. A shared agreement should cover energy distribution, maintenance, and decision-making.

Key benefits of solar in apartment buildings

• Lower shared expenses and energy bills: Self-generated electricity can reduce or eliminate costs for lighting and common services, lowering monthly fees over time.

• Environmental sustainability and reduced emissions: Installing solar panels helps the ecological transition, cutting CO₂ and encouraging responsible lifestyles.

• Increased property value and energy efficiency: A building with solar power is more attractive in the real estate market, and a better energy class means easier resale.

• Stronger community ties and collaboration: A shared project can strengthen relationships among neighbors and foster a more cooperative building culture.

• Opportunities to evolve toward shared energy models: Solar is the first step toward a more inclusive and decentralized energy future, with smart grids, peer-to-peer exchanges, and resilient local networks.
  
  
  

FAQ – Frequently Asked Questions

How is the rooftop divided for solar installations?

The division can follow ownership shares (millesimals) or be agreed upon by residents. In the case of individual systems, installations must not prevent future use by others.

What majority is needed to install a centralized solar system?

A simple majority of the assembly is required: 50% + 1 of attendees, representing at least one-third of ownership shares. Individual systems don’t need a vote, but residents must notify the administrator.

A shared opportunity to save and look ahead

Solar in apartment buildings is one of the smartest and most sustainable ways to reduce energy costs, boost property value, and actively contribute to the green transition. With tax incentives, shared consumption models, and increasingly accessible technology, turning your rooftop into a valuable resource has never been easier. Whether centralized or private, shared solar brings real benefits to everyone.