Renewable energy from your own roof with solar panels

The result of the solar calculator is based on data compiled by Sun Energia and a simulation of the solar power potential of a building’s roof, taking into account the alignment, inclinations, structures and shading factors of the roof as well as the local weather data.

The building at the address entered into the calculator may not be viable for solar panels as the roof is subject to significant shading. The calculator may also give a zero result if the building cannot be found in the database.

New buildings, in particular, may not always be found in the map database, or there may be an error in the data. In some cases, the solar power potential cannot be calculated due to inaccuracies in the map database.

You can also roughly estimate your roof’s viability for solar panel by checking how much sunshine the south-facing roof of the building gets.

1. A three-phase system will distribute the production across all the electricity-consuming phases in your home, which means that a larger share of your production goes to your own use. In the future, air-source heat pumps and electric vehicle charging points may increase your home’s electricity consumption. Because of this, a single-phase system is not a cost-effective option in the long term.
2. High-quality components guarantee ease of use. In the long run, cheap parts will cost you more. High-quality manufacturers also provide better and faster service in the event of faults or breakage.
3. We recommend acquiring your panels from a reliable company that is sure to remain in business for the entire lifecycle of your solar power system. A good salesperson will answer any use-phase questions you may have, handle your warranty issues, if necessary, and enable you to expand your system and add new products to it.

In southern Finland, the annual output of a 1,100 Wp solar power system at a 30–45-degree angle amounts to about 900 kWh per year. The total annual output in the southern parts of Finland is about the same as in northern Germany. Use our calculator to see your output potential.

Annual amount of solar radiation (click to open the picture)

Wp refers to the system’s maximum capacity in watts and kWp in kilowatts.

In the solar power survey, we will scale the system to meet your needs. The most beneficial way to use a solar power system is to set it up in a way that all the energy produced goes to your own use. Because of this, the survey is carried out on the basis of your home’s electricity consumption during a summer day.

A three-phase system will distribute the production across all the electricity-consuming phases in your home, which means that a larger share of your production goes to your own use. Moreover, air-source heat pumps and electric vehicle charging points may increase your home’s electricity consumption in the future. Because of this, a single-phase system, in other words a system that only provides electricity for one phase in your home, is not a cost-effective option in the long term.

Solar panels come with an inverter. This is a device that transforms the DC power produced by solar power into AC power so that it can be used at home and fed into the grid.

HJT stands for Heterojunction Technology. In HJT solar panels, the silicon cells are surrounded by a layer of amorphous silicon. HJT is new-generation technology that started to gain in popularity in 2023. The technology offers more reliable performance, better and improved heat resistance in solar panels.

In a solar power inspection, the most suitable solar photovoltaic system for the customer is designed and an offer on the installation work and equipment, including installation accessories, is made according to the specifications of the installation site.

You can deduct the share of your solar power package’s installation in your taxes. In 2023, the maximum tax credit for household expenses is EUR 2,250. In our invoice, you will see the share deductible as tax credit for household expenses, itemised for your convenience. The tax-deductible part is 40% of the installation costs of the solar power system’s total price, while your own contribution is EUR 100. For more information, please visit www.vero.fi.

Generally speaking, an action permit is not required when the panels are mounted in line with the slope of the roof and the building is not a protected structure. However, municipalities have not harmonised their policies regarding this matter, which is why we recommend that you contact the building supervision authorities and check the building regulations of your municipality before ordering a solar power system. Helsinki, Espoo and Vantaa, for example, do not require permits as long as the building is not an important site in terms of protected built heritage, historical value or cityscape and the system is mounted in line with the slope of the roof. Various other municipalities require an action permit from the building supervision authorities.

Helen will offer assistance in any building and action permit issues. However, the customer is ultimately responsible for handling the permits.

Helen will fill in the grid integration permit application delivered to the grid company on behalf of the customer.

You can use Helen’s solar power calculator to find out how much solar energy you could produce by mounting panels on your roof. The calculator takes into account any shade hitting your roof, such as other buildings and trees. For a detailed estimate of the best solar panel solution for you, please order a survey.

Solar panels do not require full sunshine; they will also produce electricity on cloudy days. At night, solar energy cannot be produced and any electricity needed must be taken from the grid. The best benefits and savings come from consuming electricity when the solar panels are producing it.

Solar panels should always be placed away from shade. Any shading trees or structures will affect the output of the system. It is better to build a solar power system that is smaller in terms of nominal output than a larger system that will be party in the shade.

Solar panels are practically maintenance-free and do not need any particular cleaning. Pollen is usually rinsed off by rain.

If you do not use all of the solar power you produce, you can store it in a physical electricity storage system provided by Helen. Alternatively, you can sell your overproduction to us at market prices, with the best contract on the market as we do not charge commission or other fees. Contact us and we will find the best solution for you.

The solar power systems provided by Helen cannot be used at summerhouses that are not connected to the grid. The installation site needs to have an electricity connection as our solar power systems and electricity storages must be connected to the grid.

A solar power system connected to the grid cannot be used as a backup system as the solar power system is automatically switched off in the event of any malfunctions in the grid to ensure the safety of the repair crew. The electricity storage can be used during blackouts.