How to compare solar quotes in Portugal
Eight things to check when comparing solar installation quotes, plus the seven red flags that appear most often in Portuguese quotes, and what an independent review catches before you sign.
Comparing solar quotes in Portugal is harder than it looks. Installers rarely quote the same system, use the same component quality, or describe DGEG registration in the same way. The result is that a quote for €7,200 and a quote for €6,600 may not be for a comparable system at all. These eight checks let you compare on equal terms. The seven red flags below tell you when to ask more questions before you sign anything.
Eight things to check in every quote
System size in kWp, not just panel count
A quote saying '12 panels' tells you almost nothing. Panels range from 400 W to 550 W, so 12 at 400 W is 4.8 kWp and 12 at 550 W is 6.6 kWp, a 38 percent difference in output. Always compare quotes on total kWp, not panel count.
Panel brand, model, and wattage per panel
Tier 1 manufacturers (Longi, JA Solar, Jinko, Risen, Canadian Solar) use consistent quality control and honour their warranties internationally. An unfamiliar brand with no Portuguese service network is a risk that shows up years after installation, not at the point of sale.
Inverter brand, model, and type
Know whether you are getting a string inverter, a hybrid inverter, or microinverters, and whether the inverter brand has a local service partner in Portugal. A hybrid inverter is required if you want battery storage now or in the future. Check the warranty: five years is standard, ten is better.
Battery: usable kWh, not total kWh
A battery quoted as 10 kWh typically delivers 8 to 9 kWh of usable storage. Manufacturers express capacity differently. Ask for the usable kWh figure and compare on that basis, not the headline number on the datasheet.
Panel orientation and tilt angle
A south facing roof at 35 degrees will typically produce 10 to 15 percent more than an east or west facing roof at the same tilt. Your quote should state the panel orientation and tilt, and ideally include a PVGIS yield estimate for your specific setup. If it does not, the payback estimate is unreliable.
Exactly what is included in DGEG registration
Many Portuguese installers write 'DGEG included' in the quote but handle only the EDP Distribuição technical submission. The SERUP portal registration and the certificate of exploitation are separate steps. Ask the installer to list each specific step they cover and each step that falls to you.
Warranty terms for each component
The industry standard is a 25 year linear performance guarantee on panels (typically 80 percent of rated output at year 25), a 12 year product warranty on the panel itself, and a 5 to 10 year warranty on the inverter. Workmanship warranty on the installation should be at least two years. Get all of this in writing.
Who is your contact after installation
Ask who you call if the inverter throws a fault code in three years. Many installers subcontract the work and have no ongoing service capacity. A direct answer with a named contact or a service agreement is reassuring. Vague answers are not.
Seven red flags to watch for
These are the warning signs that come up most often in Portuguese solar quotes. Any one of them warrants a direct question before you sign. More than one in the same quote is a signal to get at least one more independent opinion.
- Quote does not state the price per kWp: if you cannot calculate it, you cannot compare it
- Battery capacity listed as total kWh only, with no usable kWh figure
- DGEG registration listed as included with no itemised detail of what is actually covered
- Quote valid for 24 or 48 hours with no reason: manufactured urgency to stop you getting other quotes
- Panels listed by model code with no brand name and no link to a specification sheet
- Inverter is a brand you cannot find any reviews or service information for in Portugal
- No mention of panel orientation, roof assessment, or site visit before the quote was prepared
What an independent review catches
The checklist above is a starting point. An independent advisor who has seen dozens of Northern Portugal quotes can go further:
- Whether the quoted system size actually fits your roof area given your panel dimensions and local planning rules
- Whether the price per kWp is within the current Northern Portugal market range (€1,100 to €1,400 per kWp in 2026, excluding battery)
- Whether the inverter type is right for your usage pattern: a string inverter and a hybrid inverter are very different products at very different prices
- Whether DGEG responsibility is clearly assigned in the contract, not just mentioned in the quote document
- Whether the quoted yield calculation uses your actual municipality's irradiance data rather than a national average that flatters Northern Portugal
Go deeper with the quote red flags tool
The installer quote red flags tool walks through every warning sign in a Portuguese solar quote with plain English explanations of why each one matters.
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