How to choose the right solar panel installer

Short answer

A good residential solar installer in Romania in 2026 needs to tick three boxes:

1. ANRE certification — Tarif B or C covers everything residential needs.
2. AFM-validated if you want the Casa Verde subsidy — without it, your file won't be accepted.
3. Clear warranties — minimum 2 years on workmanship, 12 years on panels (manufacturer), 5–10 years on the inverter.

Everything else (years in business, reviews, project portfolio) is "nice to have." The three above are non-negotiable.

ANRE certifications explained

ANRE (Romania's energy regulator) issues licences for companies and individuals working on electrical installations and energy production systems. For residential PV, the relevant grades are:

Grade	Covers
Tarif A1 / A2 / A3	designing electrical installations
Tarif B	low-voltage installation execution (up to ~1 MW)
Tarif C	low-voltage and medium-voltage installation

For a 3–10 kW house system, Tarif B is plenty and it's the most common grade. Tarif C is for larger firms doing commercial work too. If a company has neither Tarif B nor Tarif C, don't hire them — they can't legally sign your grid connection paperwork.

You can verify on the ANRE website: the active certifications list is public, with company tax IDs and grade. Ask for the company's tax ID (CIF) on the first call. If they refuse, that's a clear red flag.

AFM (Casa Verde) validation

For the Casa Verde subsidy (RON 20,000), the installer must be on the current AFM list — not "we used to be" but in this session. The list refreshes between sessions.

On our city pages, companies marked with the AFM badge are on the current list. Pick from outside that list and your Casa Verde application is invalid from day one.

What to verify on the first call

Ask plainly:

• Company tax ID (CIF) — you'll use this to check ANRE and AFM yourself.
• ANRE certification — grade and number. They should publish it on their site or send it to you.
• AFM validation if you're planning Casa Verde.
• Years in business — under 2 is riskier; over 5 is fine for residential. Newer companies can be excellent but require more verification.
• Workmanship warranty — minimum 2 years. If they offer less, or "no written warranty," walk away.
• Equipment warranty — quality panels carry 12+ years product warranty and 25–30 years performance warranty; inverter 5–10 years. If the brand isn't familiar, request the spec sheet.
• References — 2–3 recent local installations. Good companies let you call previous customers.
• Contract details — turn-key price, what's included, what's NOT included, delivery timeline, payment terms (typical deposit 30–50%).

Red flags (walk away)

• Price well below market — for a 5 kW system, anything under EUR 5,000 turn-key is suspicious. EUR 4,000 in 2026 means something's missing (B-grade panels, refurbished inverter, uncertified installation).
• Refuses to share tax ID or ANRE certification.
• "Cash, no invoice" — kills your warranty, kills your Casa Verde eligibility, and exposes you legally.
• "We start today" or sign-on-the-spot pressure.
• No physical address or just mobile numbers — registered office should be verifiable.
• Skips on-site roof inspection before quoting — a serious quote requires a site survey.
• Avoids the grid connection paperwork — without the ATR (avizul tehnic de racordare), your system is illegal on the grid.

Why 450 W panels, not 600+ W

You'll see online pressure to grab "the biggest panels." For residential, that's wrong. The 2026 sweet spot is 450–470 W, not 600+. Why:

• Price per kWp: 450 W is the global volume class — high competition → best price per kWp. 600+ W is still utility/commercial-oriented — equal or worse price per kWp.
• Dimensions: 600 W ≈ 2.4 m long; 450 W ≈ 2 m. Romanian residential roofs are segmented (many faces, dormers, chimneys, vents) — large panels leave usable strips unused, costing you productive area.
• Weight: 600 W ≈ 30 kg vs 450 W ≈ 22 kg. On older roofs and converted attics the extra load matters; can require structural assessment.
• Handling: two installers can lift a 450 W up a ladder. A 600 W needs a small crane or panel lift → extra logistics cost passed back to you.
• Granularity: 450 W lets you size in 0.45 kWp steps; 600 W forces 0.6 kWp jumps. For 3–7 kWp systems (Casa Verde sizing), fine granularity matters.
• Inverter compatibility: residential inverters (Huawei SUN2000, Solis, Growatt, Sungrow) are tuned for strings of 400–500 W panels. At 600+ W the string runs fewer, hotter panels — may need a different MPPT or inverter class.
• Replacement in 5–10 years: 450 W is standardised — finding compatible panels in 10 years is straightforward. 600+ W is still evolving; replacement risk is real.

Bottom line: if an installer pushes 600+ W panels for a 50–80 m² residential roof, ask why. The right answer is "you have a large flat unsegmented surface." The wrong answer is "they're newer and better."

How to compare quotes

Get three quotes and put them side by side:

Item	Quote A	Quote B	Quote C
Capacity (kWp)
Panel brand + wattage
Inverter brand + type (string/hybrid)
Turn-key price (EUR, VAT included)
With / without battery
Workmanship warranty
Inverter warranty
Delivery timeline
AFM-validated

This table surfaces the real differences — pay particular attention to "what's NOT included" (sometimes the grid connection paperwork, sometimes transport, sometimes protections).

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See also: How much does a solar system cost? · Casa Verde subsidy