GST invoice format for a rooftop solar installer (EPC)
A rooftop solar installer's GST invoice should list module make, wattage and serial numbers, inverter model, system capacity in kWp, and DISCOM or subsidy references. Solar power generators, PV modules and solar power-based devices are in the 5% schedule. When they are supplied along with installation services, Notification 9/2025 deems 70% of the gross consideration to be goods at 5% and 30% to be the taxable service at 18%, so the invoice should show that split clearly.
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Grid-connected rooftop solar power system 5 kWp: goods portion (70% of gross consideration)
8541
1 SET
1,96,000.00
1,96,000.00
5%
Installation, commissioning and civil work for 5 kWp system: service portion (30% of gross consideration)
995468
1 OTH
84,000.00
84,000.00
18%
Solar water heater 200 LPD, ETC type
8419
1 NOS
24,000.00
24,000.00
5%
Copper earthing kit with chemical earth electrode
8544
1 SET
4,500.00
4,500.00
18%
Taxable value
₹3,08,500.00
GST (CGST + SGST, or IGST if inter-state)
₹26,930.00
Invoice total
₹3,35,430.00
Sample prices are illustrative. Check the GST rate for your exact item or service before billing.
Extra fields a solar installer invoice needs
System capacity in kWp
Clients, DISCOMs and subsidy portals all refer to capacity. Printing total kWp on the invoice ties it to the net-metering application and the sanctioned load.
Module serial numbers
Panel warranties run for decades and subsidy inspections check serials. Listing module serial numbers or attaching a serial annexure protects both you and the client.
Inverter make, model and serial
The inverter is the component most likely to need warranty service. Its model and serial on the invoice help the client claim warranty without searching for delivery papers.
70:30 valuation split
When modules and services are supplied together, the law deems 70% as goods and 30% as service. Showing the split with tax at 5% and 18% makes the computation transparent and audit-ready.
DISCOM application and net-meter number
Net-metering approval links your installation to the consumer's electricity account. Quoting the application or consumer number helps the client and the DISCOM match the paperwork.
Subsidy portal reference
Residential systems under government rooftop schemes are registered on a national portal. The registration or application ID on the invoice helps the client track subsidy release.
Standard GST invoice fields
Rule 46 of the CGST Rules applies to every tax invoice, including this one:
✓Supplier name, address and GSTIN
✓Consecutive invoice number (max 16 characters, unique for the year)
Entry 437 of Schedule I to Notification 9/2025 covers renewable energy devices and parts for their manufacture, including solar power-based devices, solar power generators and photovoltaic cells whether or not assembled in modules or made up into panels, at 5%. Solar water heaters and systems under 8419 12 are listed separately in Schedule I at 5%. Before 22 September 2025 these attracted 12%, so installers must update their invoice templates and quotations issued for later deliveries.
The deemed 70:30 split for EPC contracts
The Explanation to the same entry says that if these goods are supplied along with other goods and services, one of which is a taxable service under the works contract entry, the value of goods is deemed to be 70% of the gross consideration and the remaining 30% is deemed to be the taxable service. In practice the installer computes the gross contract price, applies 5% to 70% of it and 18% to 30% of it. The invoice should show both lines so the client and auditor can see the effective rate.
Ordinary electrical items are not solar devices
Earthing kits, AC cables, MCBs and distribution boards supplied outside the composite EPC price retain their own HSN rates, typically 18%. Inspectors look for installers who apply 5% to everything on a solar invoice. If you sell batteries, panels and wiring as separate retail items, classify each on its own rather than relying on the solar entry.
Subsidy does not reduce the taxable value
Government subsidy for residential rooftop solar is paid to the consumer after commissioning, not to the installer as part of price. GST is therefore charged on the full contract price before subsidy. Showing the subsidy as a deduction on the tax invoice would understate the taxable value; mention it only as an informational note.
E-way bills for panel consignments
Panels and inverters are bulky and valuable. Any movement of goods above ₹50,000, including stock transfers to your own site, needs an e-way bill. For a 5 kWp system, the goods portion alone generally exceeds this limit, so generate the e-way bill before the truck leaves your warehouse.
Common billing mistakes
✕Applying 5% to the entire EPC contract value instead of splitting 70% goods and 30% service.
✕Deducting the customer's expected subsidy from the taxable value on the invoice.
✕Billing AC cables, MCBs and earthing at 5% as if they were solar devices.
✕Leaving out module and inverter serial numbers, which delays subsidy inspection and warranty claims.
✕Using the old 12% rate on invoices raised after 22 September 2025 for orders booked earlier.
Solar installer GST invoice: FAQ
What is the GST rate on rooftop solar systems?
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Solar power generators, PV modules and solar power-based devices are taxed at 5%. When supplied with installation, 70% of the gross price is taxed at 5% and 30% at 18%.
What HSN code applies to solar panels?
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Photovoltaic cells and modules fall under HSN 8541. The 5% entry applies to them whether or not they are assembled in modules or made up into panels.
Is GST charged before or after subsidy?
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GST is charged on the full price agreed with the customer. Subsidy is paid separately to the consumer and does not reduce the taxable value of your supply.
What SAC code should I use for the service portion?
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Installation of a rooftop solar system is commonly billed under the works contract or installation services group; 995468, other installation services, is a typical choice. Keep it consistent across invoices.
Do solar water heaters get the same rate?
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Yes. Solar water heaters and systems under HSN 8419 12 are in Schedule I at 5%.