You've got two or three solar quotes in your inbox, and the prices range anywhere from Rp 120 million to Rp 190 million for what sounds like the same system. Somewhere in those PDFs is the answer to why, but the scopes are written differently, the brands are vague, and one quote is just a round number with no line items. Comparing them feels like figuring out if you're buying the same car when one dealership gives you a window sticker and the other texts you a number.
This checklist is for that moment. You don't need to be an electrical engineer to use it. You just need to know which 12 items belong in every complete solar quote, which line items tend to surface "later" (often after you've signed), and how to make quotes sit side-by-side so you can actually compare them honestly.
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TL;DR
- A complete solar quote needs 12 specific items. Any quote missing panel model, inverter model, battery specs, or warranty duration is incomplete. Ask for a revision before you compare prices.
- Hidden creep adds Rp 5-15M on average: extended cabling (Rp 200-500k/m), breaker upgrade (Rp 1-3M), SLO + ESDM fees (Rp 1.5-3M), structural roof reinforcement (Rp 2-8M). Surface these at survey time, not at invoice.
- Cheapest headline price is misleading. Normalize scope first: same panel brand, same inverter model, same battery kWh, same warranty terms, same included paperwork. Then compare.
- Payment terms: 50-60% down payment on equipment order, final 40-50% at commissioning or SLO delivery. Never pay 100% before install starts.
- Workmanship warranty must explicitly cover roof waterproofing. If it doesn't, ask for a written addendum before signing.
- Post-install service, including the first-year check-up, cleaning visits, and monitoring support, is often left out of quotes even though better installers include it. Ask before you sign.
The 12 items every solar quote needs
Go through any quote you receive and check for each of these. If an item is missing, send it back and ask for it specifically before you compare prices.
1. Panel brand, model name, and Wp per panel. Not just "400 Wp Tier-1 panel." The actual model: "Jinko Tiger Neo N-type JKM430N-54HL4-V" or "Trina Vertex S+ TSM-NEG9R.28." Different models have different temperature coefficients, degradation curves, and warranty terms, and they're priced differently. Confirm total kWp as well (number of panels multiplied by Wp per panel).
2. Inverter brand, model, kW rating, 1-phase or 3-phase, and whether it's parallel-capable. A Growatt SPH 3 kW is not the same as a Deye SUN-8K-SG04LP3. If your PLN connection is 7,700 VA or higher, you likely need a 3-phase unit. Parallel-capable matters if you plan to expand the system later.
3. Battery brand, model, total kWh, chemistry, depth-of-discharge spec, and cycle warranty. "10 kWh battery" means nothing without knowing if it's LiFePO4 or lead-acid, what DoD is supported, and what the cycle warranty covers. Pylontech Force-L2, BYD B-Box Premium, HinaESS PowerGem Plus are specific answers. "Lithium battery" is not.
4. Mounting type, roof penetration method, and waterproofing material. Tile hook vs. L-bracket vs. ballast (no penetration for flat concrete roofs). Type of flashing and sealant used for penetrations on tile roofs. This is where year-3 leaks come from when it's done badly.
5. DC and AC cabling specs, run distances, and breaker ratings. DC cable cross-section (typically 4 mm² or 6 mm²), total run length from panels to inverter, AC cable from inverter to the main panel, and breaker ratings at each point. Extended runs over 15 m from panels to inverter cost Rp 200-500k per extra meter.
6. PLN paperwork scope. Whether SLO (Sertifikat Laik Operasi, the operating certificate required for grid-tied and hybrid systems) and ESDM registration are included in the quoted price. These add Rp 1.5-3M in fees and 2-4 weeks of processing time. Many first-draft quotes omit them entirely and invoice them separately at the end.
7. Workmanship warranty: duration, scope, and exclusions. How many years? What counts as workmanship defect versus product failure? Does it explicitly cover roof penetrations and water tightness? Get this in writing, because "warranty included" without specifics is worthless.
8. Manufacturer warranty pass-through documentation. Confirmation that panel, inverter, and battery warranties are enforceable through the Indonesia distributor channel, not just through the installer. Ask directly: if this installer closes in 3 years, where do I take a panel warranty claim?
9. Payment terms. Down payment percentage (standard is 50-60% to release the equipment order), and what triggers the final payment: commissioning, SLO delivery, or a simple calendar date. The trigger matters more than the percentage. Avoid final payment due on "equipment delivery" before install is even done.
10. Project timeline. Survey-to-install days, install duration, target commissioning date. "As soon as possible" is not a timeline. Ask for at minimum: survey by when, equipment ordered by when, install starts when, commissioning target when.
11. Permitting fees, itemized separately. SLO (Rp 1-3M), ESDM registration (Rp 500k-1M), building permit if structural additions are needed (Rp 2-5M depending on scope). If these aren't in the quote, ask whether they're included or will be invoiced separately.
12. Post-install service terms. Is a first-year inspection included? Are panel cleaning visits included or separately priced? Is remote monitoring support included, or is that a separate service contract? Better installer companies include at least one free inspection in the first year. It's worth asking before you assume.
A quote missing items 1 through 9 is incomplete. Ask for a revision before doing any price comparison.
The hidden-creep line items to watch
The gap between quoted price and actual invoice comes from a predictable short list. Not all of these additions are unreasonable, but they should be quoted at the start, not discovered at invoice time after you've signed.
| Item | Typical cost range | When it usually surfaces |
|---|---|---|
| Extended DC cabling (per meter over 15 m) | Rp 200-500k/m | Rooftop-to-inverter distance longer than estimated in quote |
| Breaker and MCB panel upgrade | Rp 1-3M | Old panel can't handle new loads, found at survey |
| Structural reinforcement for aging roof | Rp 2-8M | Terracotta tile, old timber joists, or undersized purlins |
| SLO + ESDM certification fees | Rp 1.5-3M | Paperwork costs not initially itemized in quote |
| Grounding and earthing system upgrade | Rp 500k-2M | Required for hybrid and battery safety compliance |
| Battery rack or wall-mount platform | Rp 1-2M | No existing flat surface for battery installation |
The best time to surface all of this is during the site survey, before you've signed anything. Ask the installer directly: "Based on what you've seen at the site, are any of these items likely to appear in a revised quote after sign-off?"
If an installer can't answer that question specifically, they haven't done a thorough enough survey. A proper site visit takes two to three hours minimum and should cover a load audit, roof condition check, inverter placement confirmation, and cable route planning. A visit based on photos alone is not a complete survey.
How to compare quotes side-by-side
Once you have quotes that each cover all 12 items, you can actually compare them. The process is four steps.
Normalize brands. If one quote lists Jinko Tiger Neo N-type and another says "400 Wp Tier-1 panel" without a model name, you're not comparing the same product. Ask the second installer for the specific model. A named model is accountable; a vague description isn't.
Normalize scope. Build a table with each quote's total kWp, inverter kW rating, battery kWh, warranty years, and included paperwork. If quote A includes SLO fees and quote B doesn't, add Rp 1.5-3M to quote B before comparing totals. If quote A includes a breaker upgrade and quote B doesn't, add the estimate there too.
Normalize warranty terms. A 1-year workmanship warranty is not the same value as a 3-year warranty. The installer offering three years is taking on more risk, which usually means higher confidence in their work quality, or a higher price for that coverage. Both are honest positions; just factor them into the comparison.
Normalize payment terms. A quote requiring 70% down with the balance due at equipment delivery (before install completes) is a worse deal for you than 50% down with balance at commissioning. You're absorbing more risk in the first structure. That belongs in your comparison, not just the headline number.
After you've done all of that, price is the last variable you compare, not the first. If the scopes are genuinely equivalent, the price difference is real cost variation and you can make a decision. If the scopes aren't equivalent, the lower number is almost always missing something you'll pay for later.
When this doesn't fit your situation
This checklist is built for residential installs in the Rp 80-400M range: villa, townhouse, larger family home. A few cases where it needs adjustment:
Very small systems under Rp 30M (under 3 kWp, no battery): some items like SLO paperwork and 3-phase decisions may not apply. But still verify panel model, inverter model, cabling spec, and workmanship warranty.
Commercial systems above Rp 1 billion: you'll want an electrical engineer involved, and the quote structure starts to look more like a contractor scope of work. The 12 items still apply, but the format is different and the payment milestones will be more granular.
Off-grid installs in remote areas (Gili islands, East Bali coast, Munduk interior): add generator backup scope, extended logistics, and crew accommodation to the comparison. Those costs are real and should be quoted, not estimated later.
We'd rather say this up front than have you apply the wrong framework to your situation.
Ready to size your home?
If you're at the stage of collecting quotes but not sure what you're looking at, send them to us. We'll tell you what's missing, flag the creep items most likely for your villa or location, and give you a sense of whether the pricing is reasonable. No commitment required, and we're not in a rush to push you toward a decision.
Or use the calculator first to get a baseline sizing, then bring that into your installer conversations.
Frequently asked questions
SLO and ESDM certification fees are missing from roughly 40% of first-draft quotes we see. They add Rp 1.5-3M to the total, and because they're buried in paperwork, buyers often get surprised at invoice. Ask up front whether those fees are included or will be invoiced separately.
