Pricing a 3, 5 or 10 kW Solar Job: BOM Breakdown
How to price 3, 5 and 10 kW rooftop solar jobs in India: bill of materials, cost shares, GST at 5%, 18% or 70:30, labour, margin and market check.
Short answer: price a rooftop job bottom-up: materials from today's price sheet, plus GST, labour and transport, net-metering and portal work, a maintenance reserve for the 5-year PM Surya Ghar obligation, and your margin. In our illustrative DCR bills of materials, modules are 52–59% of material cost, the inverter about 13%, structure 14–17%, and earthing plus lightning 4–10% (higher share on small jobs). Then sanity-check against the market band of roughly ₹46,000–70,000 per kW installed.
The pricing formula
Selling price = Materials + GST + Labour + Transport + Liaison + Maintenance reserve + Overheads + Margin
Keep each line visible in your own sheet, even if the customer sees one price. That is how you know which lever to pull when a competitor undercuts you.
Bill of materials: 3 kW on-grid, DCR, elevated structure
| Group | Items and quantity |
|---|---|
| Modules | 6 × 550 Wp DCR (3.3 kWp) |
| Inverter | 3 kW single-phase on-grid |
| Structure | Elevated HDG for 3.3 kWp; 24 chemical anchors M12; 2 tubes PU sealant |
| DC side | 60 m solar DC cable 4 sq mm (red + black); 4 MC4 pairs; 20 m UV conduit; DCDB with 600 V DC isolator and Type II DC SPD |
| AC side | ACDB with 20 A DP MCB, 40 A 30 mA RCCB, AC SPD (Uc 320 V), DP isolator; 15 m Cu 2C × 6 sq mm |
| Earthing and LA | 3 chemical earthing kits (2 m); 30 m Cu 6 sq mm earth wire; 6 module bonding kits; LA kit on mast; 15 m GI strip 25 × 3 mm down conductor |
| Sundries | Lugs, glands, UV ties, tape, ferrules, danger and DC signage, nameplate |
Cost shares by size (material only, illustrative)
| Group | 3 kW | 5 kW | 10 kW |
|---|---|---|---|
| Modules | 52% | 56% | 59% |
| Inverter | 13% | 13% | 13% |
| Structure, anchors, sealant | 14% | 16% | 17% |
| DC cable, connectors, DCDB | 5% | 4% | 3% |
| AC cable, ACDB | 5% | 4% | 4% |
| Earthing and lightning | 10% | 6% | 4% |
| Sundries | 1% | 1% | 1% |
Computed from Sunlectric's October 2026 sample catalogue for 6, 10 and 20 × 550 Wp DCR modules with 3 kW single-phase, 5 kW single-phase and 10 kW three-phase inverters. Shares, not prices: plug in your own price-sheet rates, which move weekly, especially for DCR modules.
What changes with size: - 5 kW: 10 modules, 5 kW inverter, 44 anchors, 10 sq mm Cu AC cable for a 20 m run (voltage drop, see cable sizing). - 10 kW: 20 modules, three-phase inverter with two MPPTs, 1,000 V DC isolators (one 4-pole isolator per input), 1,000 V DC SPD, four-pole MCB and 100 mA RCCB, Cu 4C × 6 sq mm, 10 sq mm earth conductors.
Fixed items (DCDB, ACDB, earthing pits, LA) do not scale with kW, which is why small systems cost more per kW.
GST: two ways to bill
Itemised supply: - Modules and solar power devices (including solar inverters as part of a solar system): 5% since 22 September 2025 (check current notification) - Cables, switchgear, structures, meters, earthing, batteries and services: generally 18% - In our illustrative BOMs, material GST works out to about 8.7–9.6% blended
Composite solar power generating system (SPGS) contract: - 70% of value at 5% and 30% at 18%: about 8.9% effective
Inverters sold on their own may be challenged at a higher rate. Get your CA's opinion and invoice consistently.
Labour, transport and liaison
Price these from your own costs, not from a competitor's total: - Installation crew days (structure, modules, cabling, earthing, commissioning) - Transport and unloading, including stair carry where there is no lift - Net-metering liaison: DISCOM visits, meter testing, portal uploads - Civil items: earthing pit digging, waterproofing touch-up
The 5-year maintenance obligation
PM Surya Ghar jobs include 5 years of comprehensive maintenance from the vendor. Reserve for at least yearly visits, cleaning guidance, earth-resistance tests, SPD checks and travel. Unpriced, it eats the margin in years two to five.
Margin and sanity check
Set your margin (Studio's default is 10%; change it to suit your market). Then compare your price per kW with the market band:
| Size | Typical installed band, before subsidy |
|---|---|
| 3 kW | about ₹55,000–65,000 per kW |
| 5 kW | about ₹50,000–62,000 per kW |
| 10 kW | about ₹46,000–58,000 per kW |
If you are far above the band, check module rates and structure specification. If you are far below it, check what you left out: anchors, down conductor, SPDs, cable size or maintenance.
Where installers lose money
- Quoting on an old module rate and buying a week later at a higher one
- Forgetting stair carry, extra cable runs or a longer AC route found on site
- Under-pricing net-metering visits in slow DISCOMs
- No reserve for the 5-year maintenance obligation
- Re-work after a failed inspection
Kits vs loose material
Ordering a complete kit for a standard size (modules, inverter, structure, boards, cable, earthing and LA on one truck) saves site time and missed items. Loose ordering suits odd roofs. Either way, check the kit list against your design before dispatch.
Talk to Sunlectric
Get on our daily price sheet, order complete kits for 3, 5 and 10 kW, and send any competitor's PI to Beat-my-PI: we reply within two working hours with a match, a better price or an honest no. Season Lock fixes your January–March price in October–November. WhatsApp +91 89567 89307 (wa.me/918956789307). Sunlectric Studio builds the full BOM and price from your rates, and the Academy business module covers quoting.
Sources
- BOM quantities and cost shares: Sunlectric Studio engine and sample catalogue, Oct 2026 (illustrative)
- Market installed-cost band: Sunlectric benchmarks, Oct 2026
- GST cut to 5% from 22 Sep 2025 and 70:30 effective rate: Reslink (accessed Oct 2026)
- PM Surya Ghar 5-year maintenance: pmsuryaghar.gov.in
Questions people ask
What share of a rooftop solar job is the modules?
In our illustrative on-grid DCR bills of materials, modules are about 52% of material cost at 3 kW, 56% at 5 kW and 59% at 10 kW. The inverter is about 13%, and structure 14–17%.
How should I charge GST on a rooftop solar job?
Two common approaches: itemised supply (modules and solar inverters at 5%, most BOS and services at 18%) or a composite solar power generating system contract valued 70:30, giving about 8.9% effective. Take advice from your CA and be consistent.
How many earthing pits should I price for a 3 kW home?
Three is common practice: DC (structure), AC (inverter and ACDB) and lightning arrester, with a compliant down conductor such as 25 × 3 mm GI strip.
What margin do installers add?
It varies by market and service level. Sunlectric Studio uses a 10% default that you can change. Price labour, transport, net-metering liaison and the 5-year maintenance obligation explicitly before margin.