The price of a single panel does not tell you what it will cost to produce electricity at home. A useful decision needs a quotation for the complete installation and estimates based on your consumption, roof and electricity contract.
Update: we have removed the earlier price ranges and seller ranking. They were not dated, verifiable quotations for a particular installation. We have also withdrawn blanket savings promises and assumptions that grants are available to everyone.
Panel types: separate the material from the design
The US Department of Energy distinguishes crystalline-silicon cells from thin-film cells, made by depositing photovoltaic material on a supporting surface. Monocrystalline and polycrystalline refer to the silicon structure. Thin film does not mean every product is flexible: different supporting materials are used.
Bifacial refers to capturing light on both sides, including light reflected from nearby surfaces. It is therefore not necessarily an alternative to monocrystalline silicon. Ask the installer what that design would contribute on your roof, rather than assuming a fixed gain.
Understand the proposed savings
Spain’s IDAE relates savings to location, production and consumption during generating hours. It also distinguishes using your electricity, receiving surplus compensation and selling electricity. Simplified compensation offsets a monetary value against the energy component of the bill, subject to limits; it does not mean every bill will become zero.
Request a worksheet separating predicted generation, direct consumption and surplus. Ask which inputs come from your bills and which are assumptions. If the result depends on changing household routines, consider whether those changes are realistic in winter and during holidays too.
Compare six parts of the quotation
- Equipment: exact panel and inverter models, quantities and proposed capacity.
- Installation work: mounting, cabling, electrical protection, roof access and additional building work.
- Administration: who handles each permission, registration and notification, and any excluded costs.
- Battery: comparable proposals with and without storage, usable capacity and warranty terms.
- Total price: taxes, payment stages, financing and the complete amount payable.
- After-sales support: separate product, performance and installation warranties, and who handles a fault.
Send the same checklist to each supplier. Ask them to fill gaps before comparing totals. A lower headline figure may exclude work already covered by another quotation.
Where to start looking
IDAE’s guide identifies specialist installers, electricity suppliers and energy-service companies among the possible starting points. Consult its updated guidance and request several proposals, identifying who will carry out and register the work. Buying equipment online is not a substitute for the required design and checks.
Common questions
Should the calculation depend on a grant?
Compare the options without grants that have not been awarded. If a quotation assumes support, request the scheme, responsible authority, eligibility requirements and dates, plus who bears the cost if the application fails.
Is a battery always worthwhile?
Its inclusion in a package cannot answer that. Request comparable scenarios with and without storage, then examine the additional investment and expected use.
This guide helps compare proposals; it does not calculate a return for your home. Archive panel photograph: it identifies no recommended installer and does not demonstrate an installation procedure.
Sources consulted
Sources checked: 23 September 2026.
