A complete solar quote consists of around ten cost blocks – from the modules through scaffolding and electrical work to the registrations. Anyone who knows them can read any quote in minutes: the prices may differ, the line items shouldn't. Because what's missing from the quote isn't saved – it comes later as a supplementary bill. (As of: July 2026)
Key points in brief
- The quote has two halves: the material (modules, inverter, mounting system) and the work around it (installation, scaffolding, electrics, administration) – the second half is where the differences lie.
- Missing line items are the biggest risk: not mentioned almost never means included, but almost always means a supplementary bill.
- Lump-sum quotes are allowed and common – but the scope of work still has to be named item by item.
- The edge-case items determine the surprises: meter box, crane instead of scaffolding, core drilling, road closure.
- The fair comparison runs via the line-item list, not the total sum – the same discipline as with the technical comparison.
The two halves of every quote
The biggest reading mistake with solar quotes is jumping straight to the total sum. Because the total sum only compares something if the same scope of work is behind it – and that's exactly where quotes differ. A simple mental model helps: every quote consists of material and work around it.
The material – modules, inverter, mounting system, cables – is surprisingly similarly priced between reputable providers; here, the type specification including power class ensures you're comparing like with like. The work around it – installation, scaffolding, electrical installation, registrations, the edges of the site – is the part where quotes really differ: in price, but above all in scope. Anyone who only puts the total sums side by side is therefore often comparing a complete service with half of one – and is later surprised by supplementary bills.
The line items in detail: the walkthrough
Modules. The most prominent line item – with type, power class and quantity. What the key figures mean has its own guide; for reading costs, what counts is: verifiable specification instead of «brand-name modules».
Inverter (and optionally optimisers). The active centrepiece, also with type specification. A switch point with future impact is hidden here: hybrid-capable or not – the small extra cost now versus a system rebuild if you want storage later.
Mounting system and roof work. Substructure, fixing, roof penetrations including sealing. With in-roof solutions this item grows significantly, but replaces roof covering in return. Important: who's responsible for the watertightness of the penetrations – the interface question needs to be answered before it starts dripping.
Scaffolding and fall protection. The item most likely to be missing from cut-price quotes. It belongs in there – including the edge cases: on narrow neighbourhood streets, a road closure requiring a permit can be added, and for difficult access, a crane replaces the scaffolding. Both are normal; both need a price attached.
Electrical installation. DC cabling, AC connection, protection technology, work on the house distribution board – the path of the electricity as a cost block. This is where the most common honest extra cost for older houses sits: the meter box, which has to be adapted or replaced. A quote made after a site visit names this item; one made from an aerial photo discovers it on site.
Registrations and administration. Connection request, notification procedure, Pronovo registration including the one-off feed-in incentive, guarantee of origin, incentive applications. An inconspicuous line item that several thousand francs of your remuneration hang on – «do you handle all the registrations?» is one of the most important consulting questions of all.
Commissioning, documentation, instruction. Acceptance, safety certificate, system file, monitoring setup. Small in price, large in value – in a warranty case, the file is your lawyer.
Options: storage, wallbox, preparations. Cleanly shown as separate blocks so the core system stays comparable – including the cheap groundwork decisions (empty conduit, reserve space) that cost little now and a lot later.
Lump sum or itemised: which is better?
Both are legitimate – something else is decisive. The lump-sum quote («system fully installed: CHF X») is clear and common for standard roofs; it works if the scope of work is still named item by item – what's included has to be legible, even without individual prices. The itemised quote makes comparison and checking supplementary bills easier, but appears more complex.
The warning signs cut across both formats: a lump sum without a description of services («all-inclusive complete price» – including what?), conspicuously round sums with no recognisable derivation, and exclusions in the small print that hollow out the scope of work from behind. The comparison methodology stays the same in any case: line items side by side, mark the gaps, ask about the gaps.
The checklist: is this quote complete?
| Item | Must be identifiable | Missing: ask! |
|---|---|---|
| Modules | Type, power class, quantity | «brand-name modules» without a type |
| Inverter | Type, hybrid yes/no | Device «subject to availability» |
| Mounting system/roof work | System, penetrations, watertightness | Roof work not mentioned |
| Scaffolding/safety | included and priced | «by others» in the small print |
| Electrical installation | Scope incl. meter-box assessment | Electrics «time and materials» with no cap |
| Registrations | which ones, by whom | no mention |
| Commissioning/documentation | Acceptance, SiNa, file, monitoring | frequently missing silently |
| Options | shown separately | mixed into the core sum |
Reading checklist, as of: July 2026 – the technical counterpart to this (sizing, yield assumptions, warranties) is provided by the list of minimum technical specifications.
What line items reveal about the provider
The quote is more than a price – it's the first work sample. A line-item list that mentions the meter box reveals the site visit; a priced scaffolding item with an access note reveals the planner who stood on the street; the listed Pronovo registration reveals the company that knows the paperwork. The reverse is equally true: the quote produced from an aerial photo in an hour looks just the same – smooth, round and silent at exactly the points where your specific house would have raised questions.
That's why reading the line items pays off twice: it protects against supplementary bills – and it's the fastest character test of the provider, long before references and the works contract.
When prospective clients bring us competing quotes to assess, we don't need prices for the first diagnosis – we read the line-item list from the bottom up: registrations there? Scaffolding priced? Meter box mentioned? Documentation listed? These four lines separate the quote made after a site visit from the estimated one more reliably than any franc figure. The most common finding here isn't malice but optimism: items aren't missing because someone wants to deceive, but because nobody was on site and the edges of the project are simply unknown. The only problem is that in the end, optimism doesn't pay the supplementary bill. Our advice, in one sentence: compare quotes like shopping lists, not like price tags – the cheapest list that's missing the milk is suddenly no longer the cheapest one at the shop.
Frequently asked questions
Which line item is most often missing from solar quotes?
From experience, the edge cases: scaffolding («by others»), meter-box adaptation (unknown for lack of a site visit) and the registrations (not mentioned). All three are more expensive later than in the package – and all three can be asked about in two minutes: «Is that included, and where does it say so?»
Is a lump-sum quote less trustworthy than an itemised one?
No – the lump sum is common and entirely legitimate for a standard project. It only becomes untrustworthy without a description of services: what's included has to be named item by item even in a lump sum. «All inclusive» without a list is not a commitment, but a matter of interpretation.
Is the provider allowed to submit supplementary bills after the contract is signed?
For genuine surprises (hidden defects, unforeseeable extra work) yes – but that needs to be regulated in advance: what applies for extra effort, who decides what was «unforeseen»? That's works-contract material. Supplementary bills for items that were simply forgotten, on the other hand, are a matter for negotiation, not something to be taken for granted.
Why do quotes for the same system differ so much?
Mostly not because of the material, but because of the scope: one quote includes scaffolding, electrical adaptations and administration, the other outsources them – making it look cheaper as a result. Only the side-by-side comparison of line items shows whether the same thing is really being offered.
Do I have to understand every line item individually?
Understanding, yes – checking, no – that's what the checklist and, in case of doubt, asking are for. Your job as a client isn't the calculation, but the completeness check: are all the blocks there, are exclusions priced, is the rest explainable?
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Our quotes can be read from the bottom up.
Site visit before the price, every line item named, exclusions priced – and the registrations are included, not left dangling. Feel free to bring comparison quotes along.
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Swissolar-certified specialist company · ESTI installation authorisation (Art. 14 NIV) · in Zurich since 2017 · over 150 systems completed · a personal answer from the specialist company, no call centre
Sources: Quote and project practice of ecoEn GmbH, Zurich region (as of July 2026).
Last updated: 9 July 2026 · Author: ecoEn editorial team
