Dimora storica Montecretese

The Building

Building pre-intervention

Building post-intervention

The building is under protection being within the perimeter of ancient cores of specific historical and architectural interest.

The Solution

Solution post-intervention

What is the Solution?

A building-integrated photovoltaic roof made of small-format glass-glass monocrystalline silicon tiles by Gruppo STG was installed on the south- and east-facing slopes. The frameless tiles act as both weatherproof covering and solar generator, aimlessly replacing the original stone slabs. Cabling, DC optimisers and an accompanying battery storage unit are hidden beneath the roof structure for a clean historic appearance.

Why Does it work?

It works because the glass-glass monocrystalline tiles form a watertight, ventilated roof that is optimally tilted toward the sun, allowing high photovoltaic efficiency with passive cooling. At the same time, their frameless dark finish convincingly replicates the historic stone slabs, satisfying heritage-protection rules and enabling renewable generation without aesthetic compromise.

PROS

Heritage-compatible BIPV roof tiles on the south and east slopes—out of public view and colour-matched—preserved the listed building’s morphological and chromatic character; optical-cone analysis indicated no perceptible change to the façade. A bespoke mounting solution hides cabling and provides under-tile ventilation, while module-level optimizers improve performance and enable monitoring—an approach that proved procedurally straightforward even in a protected context.

CONS

The bespoke glass-glass tiles are considerably more expensive per kWp than standard modules and require specialist installers, raising the project’s upfront cost. Because each tile is part of the weatherproof envelope, any failure or upgrade demands careful dismantling of the roof section, complicating maintenance.

Type of installation

Replacement (building integrated - BIPV)

Part of the building

Roof only

Mounting system

aluminium frame

Orientation

South, East

Slope

Area (m²)

37.5

Availability

Yes, available on the market

Manufacturer

GruppoSTG

Model

Tegola Fotovoltaica® (nero)

PV module format

Customized modules

PV module format max

1000 × 750 × 9 mm

PV module type

Glass-Glass

PV cells technology

c-silicon

PV module efficiency

15,84%

Total PV power

6.5 kW

Surface PV power (W/m²)

information not available

PV energy production

information not available

Weight

17,3 kg per pezzo

Dummy modules used?

Frame

Overlapping

Colorization

No (black modules)

Colorization technology

Other

Glass structure

Shiny (with antireflection)

Additional documentation

Brochure-Tegola-FV-ITA.pdf

Before retrofit

After retrofit

Assessment

PV installation type

Replacement (building integrated - BIPV)

PV position

Roof only

Coloured PV

Module efficiency

15% < Efficiency <= 20%

Building alteration

Yes but the process was done reversibly ensuring that the original components of the building could be restored if needed

Investment cost

Medium High

Investment cost (Additional info)

Custom photovoltaic tiles are generally more expensive per kWp compared to traditional photovoltaic modules, both in terms of materials and manufacturing.

Circular approach

Circular approach (Additional info)

The solution is designed for durability and partial reversibility: the tiles can be repaired or replaced individually