A buyer of a solar power system asks: is the installed price visible before a request for quote, how long is the warranty on the panels, is the survey free of charge and are the financing terms visible. These decide 50 points out of 100.
aurinkoenergiakeskus.fi · Aurinkoenergiakauppa AUKE Oy (PRH 3615418-3), over 4,600 installations, solar panel and battery package solutions for detached houses; aurinkoenergiakeskus.fi
71.8SCORE
Installed price is shown100
Longest published warranty100
Survey free of charge100
Financing terms shown0
Basic metrics · 67.6
Digital quality76
Transparency75
Reachability55
AI quality score56
+ Over 4,675 installations and business ID (Y-tunnus) 3615418-3 clearly in the footer; the combination of experience and a transparent company identity builds strong trust
Basic metrics: 67.6, rank 1 · no change
– Financing terms shown: Financing is not mentioned on the front page or the installed packages page; the sitemap has no financing page.
solarum.fi · Solarum Suomi Oy (PRH 2984708-8), solar panels and air-source heat pumps turnkey, nationwide installation, battery package solutions; solarum.fi
70.7SCORE
Installed price is shown100
Longest published warranty100
Survey free of charge100
Financing terms shown0
Basic metrics · 65.4
Digital quality65
Transparency70
Reachability45
AI quality score80
+ Three clear installed-price packages on the front page: 5 kW 5,731 €, 6 kW 7,486 €, 8 kW 8,463 €, the consumer sees the price immediately without a quotation request, which is rare in the market
Basic metrics: 65.4, rank 2 · no change
– Financing terms visible: The front page has only an Apply for financing button, behind which the terms are not visible. Front page and sitemap checked, no financing page found.
savonaurinkosahko.fi · Savon Aurinkosähkö Oy (PRH 3134925-6), solar power systems for detached houses and farms, all of Finland, battery storage; savonaurinkosahko.fi
64.5SCORE
Installed price is shown100
Longest published warranty0
Survey free of charge100
Financing terms shown100
Basic metrics · 53.0
Digital quality71
Transparency45
Reachability45
AI quality score46
+ Unique annual return guarantee: 'If the panels do not produce the yield according to our calculations, you get additional panels free of charge', this is a concrete performance guarantee that few offer
Basic metrics: 53.0, rank 4 · ▲ 1 place
– Longest published warranty: The company offers an annual yield guarantee (additional panels free of charge if the yield falls short of the calculation), but the panel warranty in years is not stated on the front page, the price page, the annual yield guarantee page or the price guide.
aurinkotekniikka.fi · Aurinkotekniikka Myynti Oy (PRH 3428090-1), over 5,000 installed systems, solar and battery solutions for consumers; aurinkotekniikka.fi
53.4SCORE
Installed price is shown0
Longest published warranty100
Survey free of charge0
Financing terms shown100
Basic metrics · 58.7
Digital quality62
Transparency40
Reachability85
AI quality score56
+ 110,000+ installed solar panels and 6,200+ satisfied customers, the largest documented installation volume in the market area creates strong trust
Basic metrics: 58.7, rank 3 · ▼ 1 place
– Installed price shown: The installed price was not found on the front page, the financing page, the warranty FAQ or the site search results; a quote is requested via a form.
1komma5.com · Solar Age Oy (PRH 2778665-6), 1Komma5 Suomi, over 5,000 installed systems in Finland, solar panel + battery + charging station packages; 1komma5.com/fi
51.2SCORE
Installed price is shown0
Longest published warranty100
Survey free of charge100
Financing terms shown100
Basic metrics · 42.5
Digital quality62
Transparency35
Reachability15
AI quality score52
+ For the 1KOMMA5° Kotiakku battery system, the following is promised 'with a warranty of up to 15 years and 11,000 charge cycles', the longest battery warranty in the market area, which shows confidence in the product's durability
Basic metrics: 42.5, rank 5 · no change
– Installed price shown: The installed price is not stated on the solar panels page; only a savings estimate and an example calculation. No price or financing page was found in the sitemap.
The buying motives of these services could not be checked; the reason is shown for each one. They are not on the list as poor performers but as unscored. The result of the basic metrics is shown for comparison.
helen.fi · Helen Oy (PRH 2630573-4), the City of Helsinki's energy company, turnkey solar panel packages for detached houses and housing companies, battery storage, monitoring; helen.fi/aurinkopaneelit
NOT MEASURABLE
Digital quality66
Transparency0
Reachability30
AI quality score40
+ Extensive FAQ section 'Frequently asked questions about solar power and small-scale generation' answers the 9 most common questions, and 'Information hub for solar power producers' offers in-depth additional information, the customer is not left in the dark
– Helen directs consumer solar power plant sales to its partner Aurinkotekniikka, so there is no offering to measure on Helen's pages.
QUESTIONCan I see the installed price before requesting a quote?
Whether the company publishes the installed price of a solar power system on its own page.
Installed price published = 100, no price published = 0.
20 p
Longest published warranty
QUESTIONHow long is the warranty on the panels?
Longest product or yield warranty for a panel stated by the company on its pages, in years.
30 years or more = 100, 0 years = 0, in between directly proportional.
12 p
Survey free of charge
QUESTIONDoes the survey visit cost anything?
Whether the company states that the survey or planning visit is free of charge.
Free of charge = 100, not stated = 0.
6 p
Financing terms shown
QUESTIONCan I pay in instalments and can I see the terms in advance?
Whether the company states the financing interest rate or instalment terms on its own page.
Interest or instalments shown = 100, not stated = 0.
12 p
Basic metrics
Digital quality, transparency, reachability and AI quality score
Basic metrics × 0.5
50 p
Notes
The comparison has 6 operators. Only what the company itself states on its pages is measured: installed price, warranty, survey price and financing.
Helen has transferred its consumer solar power plant sales to its partner Aurinkotekniikka, so Helen's pages have no measurable offering and it was not scored.
The prices are for systems of different sizes, so the price is not compared in euros but by whether the company states the installed price before a quote. Missing information receives zero points and the reason is shown.
About this comparison
We scored 6 solar power system suppliers on 19 metrics. We compared package prices, battery storage, production monitoring and warranty terms.
A solar power system consists of panels, an inverter and an optional battery storage. Choosing the right size and a reliable installer determine whether the investment pays off.
What transparency means in this category
Whether the package price or €/kWp price is published clearly on the website without a request for quote (25), whether battery storage is offered and its price or features stated (20), whether a follow-up or production monitoring system is described (20), whether the length and terms of the panel and workmanship warranty are clearly stated (15), whether the installation lead time or typical schedule is stated (10), business ID (Y-tunnus) shown on the website (10)
How to read the comparison correctly: Half of the points come from buyer's questions, i.e. things the buyer finds out before deciding. The other half measures how openly the company publishes its prices, terms and contact details. Clear differences in points indicate a genuine difference: one tells you the price immediately, another only after logging in. Close scores should not be read as a ranking order, because every measurement has a margin of variation. The measurement accuracy and the full calculation formula are open in the methodology.
Customer experience is brought into the assessment separately. We also collect customer feedback and customer experiences about companies through separate surveys. The survey results will be added to the overall assessment later.
The price varies with the size of the system. A typical 5–10 kWp detached-house system costs 5,000–15,000 euros installed. The price per kWp falls as the system grows.
Battery storage is becoming more common. A battery system combined with solar panels enables self-sufficiency in the evenings and on cloudy days too, but adds 2,000–8,000 euros to the total price.
The household tax deduction covers installation work. The household deduction for installation work is 40% in 2026–2027, at most 2,100 euros per person.
Comparison guide
What to consider in the comparison
Panel yield in Finland is 900–1,100 kWh/kWp per year depending on the region.
Selling surplus electricity to the grid is possible with Lähisähkö contracts.
How Suomen Paras assesses and scores
Every company is measured with the same public formula: half of the points come from buyer's questions and half from basic metrics, which have four pillars: technical quality, transparency, reachability and AI quality score. Ranking cannot be bought, and you can see the origin of each point on the company's profile. Read the full methodology →
Expert tips
Request at least three quotes before deciding.
Check the installer's electrical contracting licence before signing the contract.
Compare both the panel warranty and the workmanship warranty separately.
Frequently asked questions
How long does the installation take?
A typical detached house installation takes one day. Processing by permit authorities may extend the total time to 2–8 weeks.
Is it worth buying the battery right away?
A battery improves the self-sufficiency rate, but the payback period is longer than with panels alone. Many installers prepare the cabling for a battery so that one can be added later.
Are you listed and would like to rank higher?
The free pre-analysis shows every item where your company loses points and which rank fixing it is enough for. The paid analysis shows what the items are and how to fix them.
Can't find your company on the list even though it should be there? Get in touch and we will include it in the next measurement round.
