Solar Energy for Apartment Buildings

You don't need a detached house to benefit from solar. Apartment buildings have unique opportunities — and challenges.

Building-Wide Systems

The most efficient approach: a single solar system on the building's roof that serves all residents.

How it works:

• Panels are installed on the shared roof
• A common inverter feeds electricity to shared areas (hallways, elevators, lighting) and/or individual units
• Costs and savings are split among participating residents

Pros: Economies of scale — cost per watt is lower for larger systems. Shared maintenance burden.

Cons: Requires agreement from the majority of owners. Organizing and managing the system can be complex.

Tenant Association Solar

In many countries, the homeowners' association or tenant association can vote to install a shared system:

1. A majority vote (usually 51% or 67%, depending on the country) approves the project
2. An installer designs a system for the available roof space
3. Costs are split proportionally (by apartment size or equal shares)
4. Savings are distributed according to the agreed formula

This model is growing across Europe and beyond, as regulations increasingly support multi-apartment prosumers.

Balcony Solar (Plug-In Systems)

A newer option for individual apartment residents:

• Small 1–2 panel systems (300–800 Wp) that mount on a balcony railing or wall
• Plug into a standard outlet with a micro-inverter
• Generate 300–800 kWh/year — enough to cover standby loads and small appliances
• Cost: €400–€900

Legal status varies: Germany and Austria have legalized them, and many other countries are developing regulations. Check local rules before installing.

Limitations: Low output, can't fully offset electricity costs, may void your rental agreement.

Flat Roof Opportunities

Many apartment buildings have unused flat roofs. Compared to pitched residential roofs:

• More surface area
• No orientation constraints (tilt frames set the optimal angle)
• Easier access for maintenance

A well-utilized apartment building roof can generate significant electricity for all residents.

Getting Started

1. Talk to your neighbors — gauge interest among building residents
2. Get a professional assessment — an installer evaluates roof capacity and structural suitability
3. Propose at the next building meeting — present the assessment and potential savings
4. Apply for subsidies — many country programs specifically target multi-apartment buildings

Check our calculator to estimate what your building's roof could produce, and find installers experienced with apartment buildings in our directory.