Frequently asked questions

The Virte Solar panels are made of  a copper-indium-gallium-diselenide (CIGS) semiconductor. They are thus neither single nor multi crystal solutions. These terms refer to various silicon-based solar panels.

These panels do not circulate water, but they produce electricity. This is why the panels are connected to an inverter that converts direct current electricity to 230 V mains electricity. The inverter is coupled to an electrical cabinet / fuse board, where all the household appliances and devices are supplied. The electricity generated by the Virte Aurinkokatto solar roof can be used in all the electricity needs of a property.

The panels produce direct current that the inverter converts to 230 V alternate current. When the inverter is connected to an electrical board / fuse board, all the produced solar energy is directly available to all electrical appliances in the household. If solar power is produced more than needed, the excess power is automatically fed to the mains network. And should the power requirement of the household appliances exceed the output of the panels, the required amount of electricity is automatically taken from the mains.

The technology of the CIGS solar film panels, imported by Miasolé, is extremely powerful. Their efficiency is 16.5 %, representing an average value of the single and multi crystal panels in the market. The CIGS technology is also very powerful to generate electricity from indirect light, the amount of which is somewhat higher in Finland than in Central Europe, as the sunset lasts longer here.

The angle and direction of the roof does not have any high impact on the overall output today, thanks to the advanced technology. However, it is not sensible to install panels on very steep panes facing north-west, north or north-east. With regard to the maximum output, the optimum orientation is towards the south with about 1:2 roof. The output starts to fall as the angle or the direction changes. With panes facing east and west, gently sloping roofs are clearly better than steeply sloping ones, as the panels are able to obtain light in a very broad angle.

The shades created by trees have quite a high impact on the output. With certain arrangements (a module-specific power electronics), this problem can be minimized, but not entirely removed.

The bonding is highly durable. The practical experience on butyl glues, used on the bottom of the panel, dates back over 30 years. The protection film is manufactured by 3M and chosen amongst over 100 different products after comprehensive tests. The operating life of the protection film has been several dozens of years, in salt fog test and demanding sunny conditions, among other circumstances, in the climate chamber tests conducted in a laboratory environment. After 25 years, the output of the panels is at least 80% of the original level. The actual product guarantee against breakdown is 5 years.

Yes, on all of the above mentioned roofs. If the installation surface is not smooth, as in strip metal roofs, a bottom plate is installed beneath the film panel and screwed to the roofing or to the ribs. The system is still considerably light (about 30 % of the weight of the normal system), being exceptionally quick to install and easy to reuse. The bottom plate increases the overall price of the system by less than 10 %.

A “6 kW system” refers to the nominal power, i.e., output of the panels in standard conditions (corresponds to a somewhat cool and sunny spring day in Southern Finland with a solar power of 1,000 W/m2). Over one hour, this kind of system generates 6 kWh (six kilowatt hours). In ideal circumstances, the system outputs over 6 kWh. A typical energy consumption of a detached house is about 15,000 kWh per year. A 6 kW system, optimally installed in the south-western coast of Finland, can generate max. 5,500 kWh per year.

The size of the system is influenced by the properties of the house. In electrically-heated detached houses, it is sensible to aim for 30 % output of the overall consumption. That is, with an annual consumption of 15,000 kWh, the optimum size for a solar energy system is probably about 6 kWh, which generates about 5,000 – 5,500 kWh per year in Southern Finland. If there is a separate heating system in the house, such as district heating, oil heating and/or cooling air conditioning, over 50% output of the overall consumption of electricity can be reached for. Enlargening the size of the system does not make the household self-sufficient, as the production peak is during the summer and from November to January, the output is close to zero, anyway. If the system is over-dimensioned, it creates excess production in the summer and still, in the winter, almost all of the electricity must be bought from an electrical network company.

Should the solar energy be produced over one’s own need, the rest is bought by a power company, if an appropriate agreement has been signed. The excess electricity can be sold to any power company. It should be noted that the power company only pays for the electricity; not for the taxes or transfers, that is, it pays for about 30 % of the overall costs of the electricity procurement. With the current purchase prices, the production of excess electricity is not currently profitable, so it is important to dimension the system to suit the needs of the property.

The price is influenced by

  • installation costs - the location of the site and other things related to the installation, such as the steepness and height of the  roof
  • the size of the procured system
  • additional properties, such as batteries, battery-readiness etc.
  • the need for bottom plates

The panels are not sold separately, but as an overall delivery.

We will calculate an offer, when you send us an invitation for tenders to

The solar energy system has a very long payback time. The real savings/yield depend on the development of the electricity price and can thus fluctuate substantially, which one cannot be aware of during the time of investment. At the present level, the payback time is much over 20 years, in general. An annual return of 3 – 6 % can be expected for the investment. The return on the forthcoming years depends on the price development of the electricity.