Solar thermal installation in Bulle: A comprehensive guide for homeowners

1 °C and about 108 frost days per year. These conditions underline the importance of a robust thermal installation to meet heating and domestic hot water needs, especially with 3,544 heating degree days.

Solar thermal energy proves particularly relevant for supplementing your heating system, especially during periods when global solar irradiation reaches 1,362 kWh/m²/year.

The best time to undertake this work is ideally during the replacement of your boiler or during a comprehensive renovation of the building's thermal envelope.6 °C, optimizing hot water production during the summer months helps preserve your main heating systems.

As a 'Gold Energy City' since 2020, renewed in 2024, Bulle actively encourages such energy transitions, making every project a direct contribution to local sustainability.

The sizing of your solar thermal installation depends directly on your actual hot water consumption and the type of heating system in place.

There are mainly two types of collectors : flat plate collectors, which are robust and well-suited to summer needs, and evacuated tube collectors, which perform better when sunlight is lower.

Solar thermal collectors generally cover a large part of the hot water demand in summer, thus reducing the use of your boiler over several months.

To ensure the success of your project, it is essential to consider the aesthetic and functional integration with the roof. Combining collectors and a heat pump requires a rigorous sizing study to ensure that both systems communicate effectively.

The choice of storage tank must also be adjusted : too small a volume will limit your autonomy, while an excessive volume may lead to unnecessary heat losses.

Carefully analyze the intelligent control options that allow for optimizing output according to the weather conditions specific to Bulle, where irradiation varies significantly throughout the seasons.

The building stock in Bulle is diverse, mixing old stone structures with more recent dwellings. Before any intervention, it is crucial to carry out a diagnosis of the state of your roof and the supporting structure.

For buildings constructed before 1990, testing for hazardous substances, particularly asbestos, is a mandatory step during any renovation project or installation of equipment on the roof.

Older roofs may require reinforcement work or repair of insulation before the installation of solar collectors to prevent any subsequent thermal bridges.

Verifying the tightness of existing piping networks is also essential. In the case of comprehensive energy renovation, solar thermal should not be thought of in isolation but integrated into a global energy management approach.

Older buildings may present constraints regarding the routing of pipes between the attic and the technical room.

A local professional will be able to identify these specifics and advise you on the best connection techniques to minimize impact on the interior structure, while ensuring optimal system performance in the long term.

In Bulle, as in any municipality, the installation of solar collectors is subject to certain planning and heritage protection rules.

Although federal law largely facilitates the installation of solar systems, it is imperative to consult the technical department or urban planning office of the municipality of Bulle before signing any quote.

Certain protected areas or listed buildings may impose restrictions on the appearance of the collectors or their integration method into the roof (roof integration rather than on-roof mounting).

Submitting an authorization request is an indispensable step to validate the conformity of your project with the Local Planning Scheme (PAL). Never start the work before receiving official validation.

Also, check requirements concerning neighbors, especially if your collectors risk causing glare or if their installation significantly changes the exterior appearance of a protected neighborhood.

A proactive approach with municipal authorities ensures the serenity of your construction site and avoids any risk of appeal or the obligation to dismantle after installation.

The energy transition is supported by concrete incentive schemes in Fribourg. For solar thermal, you can benefit from specific cantonal grants, detailed according to a current scale.

The golden rule is to always submit the grant application before starting the work; any invoice issued or work started before the validation of the request may lead to the refusal of financial aid.

Consult official platforms like 'Le programme Bâtiments' to know the forms and exact conditions applicable to your project.

Regarding taxation, investments in renewable energy and the improvement of energy efficiency are deductible from your taxable income. If you own a property older than 10 years, you can deduct the actual costs or opt for a flat rate of 20% of the rental value (20% of the rental status or gross income of the properties).

For buildings less than 10 years old, this flat rate is 10%. A very advantageous point is the possibility of carrying forward the excess of investment costs to the following two tax periods if your expenses exceed the income of the property for the current year.

Planning a solar thermal installation in Bulle must integrate local weather conditions. With 108 frost days per year, it is recommended to favor temperate seasons, spring or autumn, to avoid extreme conditions that complicate work on the roof.

The project generally begins with the installation of anchors on the roof structure, followed by the installation of solar collectors. Once the collectors are fixed, technicians proceed with the hydraulic connection to the technical room located inside the house.

A critical step then occurs : connection to the storage system (tank) and commissioning of the hydraulic circuit. This phase includes filling the heat transfer fluid, a meticulous operation that requires perfect sealing. Finally, the control system is configured according to your specific needs.

Although the overall duration depends on the complexity of your roof and the accessibility of the technical room, rigorous administrative preparation beforehand allows these steps to be completed without major interruption once the material is delivered to the site.

Before contacting companies, check the condition of your roof to avoid unforeseen repairs. Ensure you have your hot water and heating consumption invoices from the last three years in hand. Contact the Bulle urban planning department to confirm constraints related to your zone.

Check if roof insulation is necessary to optimize the overall performance of your house. List all available technical access points between your roof and the current boiler room. Prepare a document summarizing the characteristics of your current heating system to facilitate sizing.

Do not forget to check the Fribourg cantonal grants and verify the grant conditions before committing. Finally, request at least three detailed quotes to compare the technical solutions offered.

By following this preparation, you will save valuable time during discussions with installers. Good knowledge of your actual needs will avoid oversizing, which is often a source of efficiency losses.

Be particularly vigilant about the quality of the materials offered in relation to the snow and wind characteristic of the region. A structured approach guarantees not only a durable installation but also tax and budgetary optimization in line with the city's objectives.