Hot water from the sun. Directly from your balcony.

Turn the glazed surface of your balcony into a discreet source of energy.

Our system uses semi-transparent, tinted, or colored photovoltaic glass installed on the balcony to produce electricity locally. The energy is used directly to heat domestic hot water through a standard electric boiler.

Why balconies?

Because most apartments do not have real access to the roof.

Conventional photovoltaic panels are difficult to install on apartment buildings. You need space, approvals, electrical routes, agreements, and interventions in the common parts of the building.

Instead, many apartments already have an unused energy surface: the glazed balcony.

Photovoltaic glass uses this surface to produce energy exactly where it is consumed: inside the apartment.

How the system works

The photovoltaic glass produces direct current during the day, depending on light, orientation, season, and weather conditions.

During daylight hours, the energy produced by the glass is sent directly to the electric boiler, where it heats domestic hot water.

In the evening, the system automatically switches to the grid to complete the hot water demand, so that hot water remains constantly available.

In practice, the boiler becomes the “battery” of the system.

It stores the energy produced during the day as hot water, without the cost, losses, and complexity of an electric battery.

The system works locally, inside the apartment.

Why we do not use an inverter and batteries

For an apartment, a conventional photovoltaic system with an inverter and batteries can become expensive, complicated, and difficult to recover financially.

The inverter and the battery increase the initial cost of the system and reduce the net energy available to the user because of conversion losses, storage losses, and self-consumption.

We chose a simpler and more efficient solution for apartments: the energy produced by the photovoltaic glass is used directly to heat domestic hot water.

The boiler practically becomes the “battery” of the system.

It stores the energy produced during the day as hot water, without the cost, losses, and complexity of an electric battery.

This keeps the system more affordable, more robust, and better suited for apartment buildings.

What benefits do you get?

1. You reduce the cost of hot water

A significant part of the energy needed for hot water can come directly from the sun.

In the pilot system tested in an apartment in Bucharest, the photovoltaic glass covered approximately 42% of the energy required for hot water over more than 32 months of real operation.

This is not a simulation.

This is not an optimistic estimate.

These are measured data from a real apartment.

2. You reduce the heat entering through the balcony in summer

Semi-transparent, tinted, or colored photovoltaic glass reduces part of the solar radiation entering through the balcony.

This means less overheating in summer and lower air-conditioning consumption.
The glass does not only produce energy.

It also works as integrated solar protection.

3. You use a surface that already exists

The balcony is already there.

You do not need a roof.

You do not need land.

You do not need a separate structure for conventional panels.

Instead of allowing the glazed surface to only let heat in, it can produce useful energy for the apartment.

4. You get a discreet solution integrated into the balcony

The glass looks like modern tinted or colored glazing, similar to decorative or solar-control glass already used on balconies and façades.

It is not made of conventional panels mounted on the façade.

It does not take up space inside the apartment.

It does not radically change the appearance of the building.

The solution is suitable for enclosed balconies, existing frames, or new projects where the glass can be integrated directly into the window frames.

What apartments is it suitable for?

The solution is recommended for apartments with balconies facing:

The best results are obtained with southern orientation, but east and west can also be effective, especially for local hot water consumption.

The system is suitable for apartments that already have an electric boiler or where one can be installed.

What apartments is it not ideal for?

That is why each balcony must be assessed beforehand.

Orientation, glass dimensions, shading, hot water consumption, and the possibility of installing a boiler all matter.

Indicative configurations

The final configuration is defined according to each apartment, but as a general guide the systems can be grouped as follows:

How much can you save?

The savings depend on several factors:

It is not a huge amount.

But it is not insignificant either.

It is a saving that repeats every year.

Payback period

Depending on configuration, consumption, and energy prices, the payback period can be approximately 6–7 years in a favorable case.

After this period, the system continues to produce energy and reduce bills.

The goal is not to turn the apartment into an energy-independent home.

The goal is more realistic: to use an existing surface to reduce an important part of the apartment’s recurring costs.

The photovoltaic glass is integrated into the balcony area and can have a tinted or colored appearance, with a reduced visual impact compared with conventional photovoltaic panels.

For special-status buildings, historical monuments, or façades with strict rules imposed by urban planning documentation, additional conditions may apply.

For most ordinary balconies, the solution is designed to be simple, discreet, and visually low-impact.

Installation on an existing balcony or in new projects

Photovoltaic glass can be used in several ways:

For new buildings, the glass can be integrated directly into the architectural concept of the façade.

For existing apartments, the solution is adapted according to the balcony and the available structure.

Tested in a real apartment

Our pilot system has been operating in an apartment in Bucharest since October 2023.

The measured data show that photovoltaic glass can cover a significant part of the energy required for domestic hot water.

After more than 32 months of operation, the average solar contribution was approximately 42% of the energy required for hot water.

This shows that solar energy can be used practically in apartment buildings, not only on roofs or in photovoltaic parks.

See the system in operation

For those who want to see what the installed solution looks like and how it works in practice, we have prepared several video materials.

We recommend watching these materials to better understand the principle of the system and how it can be adapted for other apartments.