How to Compare Two Solar Quotes in Singapore, Line by Line
Two quotes for the same roof rarely describe the same thing, even at a similar headline price. Here is a real worked example showing what actually explains the gap, line by line, and which quote comes out ahead once it is accounted for.
Quick answer
Two Singapore solar quotes rarely describe the same thing, even at a similar headline price. Normalise both to price per kWp first, then compare warranty depth, scaffolding inclusion, generation estimate basis, and payment structure line by line, since these usually explain a price gap that looks confusing at a glance. The cheaper quote on paper is not automatically the better deal once they are accounted for.
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Line items that usually explain most of the price gap between two Singapore solar quotes: price per kWp, scaffolding inclusion, warranty depth, generation estimate basis, and deposit structure
Two quotes for the same roof rarely look alike. One states a single lump sum; the other itemises ten lines. One guarantees a specific generation figure; the other doesn't say how its number was calculated.
Comparing the two headline prices alone hides more than it shows. A lower number can mean a genuinely better deal, or it can mean a thinner warranty and bundled corner-cutting, and the price alone doesn't tell you which.
- Normalise both quotes to price per kWp before comparing anything else, since system sizes rarely match exactly.
- Warranty depth, scaffolding inclusion, generation estimate basis, and deposit structure usually explain more of a price gap than panel brand does.
- A cheaper quote's true 25-year cost can still come out lower even after every gap is accounted for, but the gap itself is what deserves a direct follow-up question, not an assumption either way.
- Reject both quotes and get a third if neither states a BCA ME03 license number, a Defects Liability Period, or a clear generation estimate basis.
What's the first number to normalise before comparing anything else?
Price per kWp: total quoted price divided by system size in kWp. A typical Singapore landed home installation runs roughly S$1,000 to S$1,600 per kWp installed, so converting two quotes to this figure first is what makes them comparable at all. See solar panel cost by system size for the full pricing breakdown this band is drawn from.
Do both quotes actually describe the same system?
Confirm the kWp figure itself first, since installers sometimes round to the nearest panel count differently for the same roof. Then check panel brand and tier, inverter brand, and whether both quotes were built from an actual site survey of your specific roof rather than a generic estimate based on property type alone. Two quotes for genuinely different systems are not directly comparable no matter how close their prices land.
What does a real side-by-side comparison actually look like?
Take a composite, illustrative example built from Sunnify's own reference figures, not two real companies: two quotes for the same 15kWp terrace house roof.
| Line item | Quote A | Quote B |
|---|---|---|
| Total price | S$19,500 | S$17,250 |
| Price per kWp | S$1,300 | S$1,150 |
| GST treatment | Stated inclusive | Not stated |
| Scaffolding | Itemised separately | Folded into "installation" |
| Panel product warranty | 12 years | 10 years |
| Panel performance warranty | 25 years, 87% at year 25 | 25 years, 84.8% at year 25 |
| Workmanship warranty | 5 years | 12 months |
| Defects Liability Period | Stated, 12 months | Not stated in the quote |
| Inverter | Hybrid-ready string, 10-year warranty | Standard string, 10-year warranty |
| Generation estimate | 14,900 kWh/year, stated P90 | 18,000 kWh/year, basis not stated |
| Deposit structure | 20% on signing | 40% on signing, before survey |
| SP Group paperwork | Installer handles, stated | Not mentioned |
Why does the generation estimate gap matter more than it looks?
Run each figure back through Singapore's reference yield of roughly 1,106 kWh per kWp installed. Quote A's 14,900 kWh implies about 993 kWh/kWp, close to 90% of the reference yield and consistent with a genuinely conservative P90 figure. Quote B's 18,000 kWh implies about 1,200 kWh/kWp, above the reference yield with no stated basis.
That's not automatically wrong. An exceptionally clean, unshaded, well-oriented roof can outperform the reference, but a quote claiming above-reference generation should say why, and whether the figure is a P50 or P90 estimate.
See the P50/P90 estimates guide for what these terms actually mean and why the gap between them matters for a savings projection.
How do you turn this into one real number, a 25-year comparison?
Apply the same total cost of ownership framework to both: upfront price, plus one inverter replacement around S$2,500, plus roughly S$400 a year in maintenance across 25 years. Quote A's nominal 25-year cost comes to roughly S$19,500 plus S$2,500 plus S$10,000, about S$32,000.
Quote B's comes to roughly S$17,250 plus S$2,500 plus S$10,000, about S$29,750. See the total cost of ownership framework for the full four-component breakdown this comparison is built from.
Does the GST question actually change the comparison?
Yes, and it's worth resolving before treating this gap as final. Singapore's GST rate is 9%.
If Quote A's S$19,500 is genuinely GST-inclusive as stated, and Quote B's S$17,250 turns out to be GST-exclusive once you ask directly, the real comparable price for Quote B becomes roughly S$18,800 after GST. That alone shrinks the 25-year gap from roughly S$2,250 to well under S$1,000, before the warranty or Defects Liability Period gaps above are even weighed in.
This is exactly the kind of question a vague quote leaves for you to ask, rather than answering upfront. See GST and solar panels in Singapore for how this applies more generally.
So which quote is actually better?
On the cost framework alone, Quote B looks cheaper over 25 years, using its own uncorroborated generation figure and before the GST question above is actually resolved. That headline gap doesn't include what a shorter workmanship warranty, an unstated Defects Liability Period, or an unverified generation estimate are actually worth if any one of them becomes a real problem later.
Once GST is actually resolved, the real gap is likely well under S$1,000, not large enough to treat as decisive on its own. It's more useful as the reason to go back to Quote B's installer with specific questions, using the 25-point buyer checklist, than as a reason to pick either quote outright before those gaps are closed.
When should you reject both quotes and start over with a third?
When neither quote names a specific BCA ME03 license number you can verify on BCA's own contractor registry, when neither states a Defects Liability Period at all, when both apply pressure to decide within 24 to 48 hours, or when either quote's price per kWp sits meaningfully outside the S$1,000 to S$1,600 band with no explanation offered once you ask directly. Two flawed quotes don't average out to one good decision.
What's the actual next step?
Run the Sunnify solar estimate before requesting quotes, so you already know what a fair system size and price range look like. Once you have two or more real quotes, work through the solar buyer's checklist against whichever one comes out ahead here, since a strong line-by-line comparison narrows the choice, it doesn't replace the full pre-signing check.
See is solar worth it in Singapore for the broader economics this comparison sits inside, and how to evaluate a savings guarantee if either quote includes one.
FAQ
Frequently asked questions
No. A lower price can just as easily mean leaner overhead or a smaller margin as it can mean a corner cut somewhere. The point of comparing line by line is finding out which explanation actually fits a specific quote, not assuming either one by default.
Price per kWp first. Two quotes are rarely for the exact same system size, so comparing total price alone can make a smaller, well-priced system look more expensive than a larger one that costs more overall but less per kWp installed.
Normalise both to price per kWp and to a common annual generation figure, using the same reference yield for both, before comparing anything else. Comparing a 12kWp quote against a 15kWp quote on total price alone is comparing two different products.
At least two, ideally three. A single quote gives no comparison point at all, and two quotes that land close together on price and terms is itself a useful confirmation that neither is a pricing outlier.
No, and it's worth asking about directly if either quote states a projected annual saving rather than just a generation figure. A higher assumed self-consumption percentage produces a higher projected saving from the same system, even though real self-consumption depends on your household's own usage pattern, not on which installer you choose. Sunnify's own estimate uses a reference 25% split for comparability across system sizes; a quote assuming a meaningfully higher figure without asking about your actual usage is projecting a more optimistic saving than your real habits may support.
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