Why Installer Quality Matters More Than Panel Brand
Swiss homeowners often spend hours comparing panel brands and inverter models. Those decisions matter — but the quality of your installer matters more. A mediocre installation of premium Tier-1 panels will underperform a well-executed installation of mid-market modules. Poor cable management, incorrect tilt brackets, undersized wiring, or a missing DC isolator can cost you yield, create fire risk, and void warranties.
In Switzerland, this is compounded by the regulatory environment. The VSE NA/EEA-CH (Swiss grid connection standard) requires licensed electricians to sign off all grid-connected PV installations. That means the person on your roof must hold a Swiss federal electrician's licence (Elektroinstallateur EFZ) or equivalent — not just a solar training certificate.
The Solarprofi Label Explained
SwissSolar and Swissolar-affiliated bodies issue the Solarprofi quality label to installers who meet a defined set of criteria:
- Technical qualification: Lead installer holds a federal electrical or roofing qualification plus a recognised solar training certificate
- Insurance: Adequate professional liability coverage
- References: Documented completed installations
- Continuing education: Annual upskilling requirements to retain the label
The label is not legally mandatory — any licensed electrician can legally install solar — but it signals that a company has invested in dedicated solar expertise. When comparing quotes, filter first for Solarprofi-labelled contractors or equivalently verified professionals.
→ Still unsure if the maths add up? Check your personal payback period — it takes 60 seconds.
Other reputable markers include membership in Swissolar (the national solar industry association) and quality management certifications such as ISO 9001.
Polysun: Switzerland's Gold Standard for Yield Simulation
Polysun, developed by Vela Solaris in Winterthur, is the simulation software most respected by Swiss engineers for yield planning. It models:
- Site-specific solar irradiance using Meteonorm weather data calibrated for Swiss micro-climates
- Shading analysis from trees, chimneys, and neighbouring buildings
- Temperature derating — critical in alpine locations where midday summer temperatures affect panel efficiency
- Self-consumption and grid injection ratios based on household load profiles
- Battery sizing for maximised autarky
When an installer provides a quote with a Polysun simulation report, you can compare predicted yields between contractors on an equal basis. Ask for the P50 yield figure (the median expected annual generation) and the specific yield (kWh per kWp installed). A 7 kWp south-facing system in Zurich should produce 900–950 kWh/kWp; significantly lower figures warrant explanation.
| Planning tool | Used by | Strength | Limitation |
|---|---|---|---|
| Polysun | Swiss engineers, premium installers | Swiss weather data, detailed shading | Requires trained operator |
| PVsol | German-market focus, some CH installers | 3D roof modelling | Less Swiss-specific climate data |
| PVGIS (free) | DIY research | Quick estimates | No local shading, coarse data |
| Helioscope | Growing in CH | 3D layout, fast | US-centric defaults need manual correction |
Questions to Ask Every Installer
Before accepting a quote, ask the following:
Planning and design
- Can you provide a Polysun or equivalent simulation report with the P50 yield figure?
- What shading assumptions have you made?
- How did you size the inverter relative to the panel array (DC-AC ratio)?
Certification and compliance
- Who is the responsible electrician (Verantwortlicher Elektroinstallateur) and what is their licence number?
- Are you Solarprofi-labelled or a Swissolar member?
- Will you handle the Pronovo EIV registration on my behalf?
References and experience
- How many installations have you completed in the past 12 months?
- Can you provide contact details for two or three recent customers in my canton?
- Have you worked with my local grid operator before?
Warranty and service
- What is the workmanship warranty on the installation itself (separate from panel and inverter warranties)?
- Who do I call if there is a fault in year three?
- Do you offer a monitoring setup and alert service?
Red Flags to Watch For
- Quotes that arrive without a yield simulation
- Pressure to sign within 24–48 hours
- Unusually low prices that exclude grid connection costs or scaffolding
- No mention of Pronovo EIV registration in the quote
- Reluctance to provide installer references
- Vague answers about which electrician will sign the commissioning protocol
Get instant quotes from vetted Swiss installers through Comparisun — each one pre-screened for Solarprofi credentials and Swissolar membership.
Using Comparisun to Pre-Screen Installers
Comparisun's Swiss installer network includes only verified, insured professionals. When you request quotes through the platform, each installer's certification status, Swissolar membership, and recent review scores are surfaced alongside their price. This lets you compare not just the CHF figures but the quality signals behind each offer.