1. Assess the site before choosing panels
Record roof condition, orientation, shading, access and planned work. Have structure, waterproofing, snow and wind assessed for the proposed layout. For balcony solar, clarify mounting, owner or condominium rights, equipment and electrical procedures before connection. Small or removable equipment does not automatically remove the need for approval or assessment.
2. Read the tariffs for your address
Identify the grid operator and tariff category. Separate energy, network, metering, taxes and fixed fees. ElCom reports a 2026 median of 27.7 ct./kWh for a typical H4 household using 4’500 kWh a year, lower than in 2025. This benchmark does not replace your tariff or the variable cost actually avoided through solar.
3. Define surplus payments and billing
Request the feed-in contract, tariff period, metering and treatment of guarantees of origin. Purchases and feed-in are different flows; clarify how each is valued and when payments occur. The new feed-in rule announced by the Federal Council applies from 1 January 2027 where producer and grid operator have no agreement. Do not treat a future price as confirmed income.
4. Compare a physical battery and a virtual contract
A battery stores energy on site within its capacity, power and loss limits. A virtual offer is a credit or billing contract; it does not keep your electrons for winter. Compare purchase cost, subscriptions, network fees, taxes, caps, expiry and exit terms. For backup, specify equipment, circuits, power and tests for the complete system.
5. Assess a business’s demand peaks
Peak shaving may be useful when the bill includes measured demand charges. Check the measurement interval, tariff and load history. Calculate what the battery and controls can reduce given power, reserve and availability. Compare the benefit with investment, losses and service; a battery does not guarantee removal of every peak.
6. Calculate roof constraints and bifacial gains
A flat roof does not require one universal tilt or ballast. Compare mounting, loads, drainage and access. Bifacial modules also use rear-side light; the gain depends on the reflecting surface, height, shading and mounting. Request a site simulation rather than turning albedo or snow into a guaranteed gain percentage.
7. Define financing and responsibilities
Compare direct purchase, borrowing and third-party investment against their commitments. For roof leasing, define rent or energy purchases, duration, indexation, access, maintenance, reroofing, building sale and contract end. Identify who pays for each intervention and carries each risk. Third-party finance does not automatically remove owner costs or responsibilities.
8. Coordinate added storage and EV charging
For an addition, record existing models, electrical limits, software and interfaces. AC or DC coupling requires a compatible configuration, not just a brand name. In shared parking, assess building demand, available current per phase and charging needs. Define metering, priorities, fault behaviour and tests with the responsible professionals.
9. Compare heating options and quotations
Solar thermal produces heat; PV produces electricity that can power a heat pump. Compare monthly demand, useful energy, auxiliary supply, maintenance and complete systems. Then assemble installed price, confirmed grants, procedures, warranties and handover terms. Distinguish electrical permissions from voluntary professional labels. Keep assumptions and records; no combination guarantees the same financial return for every building.