Industry playbook
Solar installers & EPC companies
How solar installers automate project costing, serial tracking and GST with hisabkitab
Picture a rooftop solar installer completing 15 to 20 residential systems a month, plus the occasional commercial rooftop. Each project needs panels, inverters, structures and cabling sent to site, payments come in stages, many customers use government rooftop subsidy schemes, and completed systems often move to annual maintenance contracts.
The challenges
Why solar projects are harder to account for than they look
Every project is a mini-EPC
A rooftop job combines panels, inverter, mounting structure, cables and installation labour. Material for several sites is bought together, so without project tagging, nobody knows whether a 5 kW system was quoted at a profit or a loss.
Composite supply and GST
Solar systems supplied with installation are typically treated as a composite supply, with a notified deemed split between goods and services and different rates on each portion. Getting the split and rates wrong on the invoice is a common and costly mistake.
Serial numbers for warranty and subsidy paperwork
Panel and inverter serial numbers are needed for warranties, inspections and subsidy documentation. When they sit on loose sheets, finding them for a service call or a portal upload wastes hours.
Staged payments
Customers pay an advance, a further amount on installation, and the rest after commissioning or net-metering. Tracking which stage each customer has paid across dozens of projects becomes a spreadsheet problem.
Maintenance contracts after handover
Annual maintenance and cleaning contracts bring steady revenue, but only if they are billed on time every year and reminders actually go out.
A day in the life
A day before vs after hisabkitab
Before
Quotations are made in a spreadsheet and re-typed into an invoice after installation.
Material for several sites is issued from the store without a record of which project used what.
Serial numbers are photographed on site and saved on the engineer's phone.
AMC renewals are remembered when a customer calls with a problem.
With hisabkitab
Quotations are raised in hisabkitab and converted into invoices with the correct goods-services split.
Material goes to each site on a delivery challan tagged to the project.
Panel and inverter serials are recorded on the invoice as custom fields and searchable later.
AMCs are set up as recurring invoices, and payment reminders go out automatically.
Solutions
How hisabkitab solves it
Project profitability
Custom Field (Transaction level) for Project + Bill-wise Profit Report
Tag purchases, challans and invoices with a project ID. Bill-wise profit shows the margin on each system, so quotes for the next job are based on real costs.
System sizing on quotes
Custom Field (Item Level) + Formula
Store watt-peak per panel on the item; the formula System size (kWp) = Panels × Wp ÷ 1000 prints on the quote and invoice.
Serial numbers
Custom Field (Transaction level) + Serial No Tracking Report (Advance)
Capture panel and inverter serials on the invoice. On Advance, the Serial No Tracking Report traces each unit from supplier to customer.
Material to site
Delivery Challan
Send material to each site on a challan tagged with the project, and convert it when the invoice is raised.
Staged payments
Estimate/Quote → Invoice + Customer Outstanding
Record advances against the customer ledger, raise invoices as stages complete, and see outstanding by stage in one report.
AMC revenue
Recurring Invoice + Auto-payment reminder
Set annual maintenance contracts as recurring invoices so they are billed on time, with automatic reminders.
Inside the software
Built for your books
Custom formula example
System size (kWp) = Panels × Watt-peak per panel ÷ 1000. Example: 10 panels × 540 Wp ÷ 1000 = 5.4 kWp.
4-level grouping
Items: Solar → Panels → Mono PERC → 540 Wp. Customers: Segment (Residential / Commercial) → City → Sales executive → Customer.
Reports you’ll use
Bill-wise Profit Report · Customer Outstanding Report · Stock Summary · Serial No Tracking Report · GST Report · Dispatch Report
Compliance notes
Solar modules and many renewable energy devices moved to 5% GST in September 2025, while installation services are taxed at the services rate, and supply-and-installation contracts follow a notified deemed split between the two; confirm the current split and rates with your CA before invoicing. Subsidy schemes have their own documentation requirements outside your books. Consignments to site above ₹50,000 can need an e-way bill.
Recommended plan
The plan that fits
Boost
₹4,999/year, exclusive of 18% GST (or ₹9,999 for 3 years)
Item and transaction custom fields, Recurring Invoice for AMCs, Bill-wise Profit Report and up to 1,500 e-way bills a year on Boost suit an installer handling one site at a time. Multi-site EPC companies should choose Advance for serial tracking, AI-OCR and unlimited e-way bills.
FAQs
Frequently asked questions
How do I show the goods and services split on a solar invoice?
Set up the system with separate goods and service lines that follow the notified deemed split for composite solar supplies, each with its own HSN or SAC and rate. hisabkitab applies the tax line by line. Confirm the current split and rates with your CA, since they have been revised over time.
Can I record panel and inverter serial numbers?
Yes. Add serial number fields at transaction level and capture them on the invoice. They print on the bill and are searchable for service calls and documentation. On Advance, the Serial No Tracking Report traces each unit from the supplier's bill to the customer's invoice.
How do I know if a project made money?
Tag every purchase, challan and invoice with a project ID. The Bill-wise Profit Report then shows the margin on each system, which tells you whether a 3 kW or 5 kW package is priced right, and whether specific brands or structures are eating into profit.
Can hisabkitab bill AMCs automatically?
Yes. Recurring Invoice on Boost raises annual or quarterly maintenance invoices on schedule, and Auto-payment reminders follow up on WhatsApp and email. AMC revenue stops depending on someone remembering, and customers get a clean, regular invoice every cycle. Each AMC also shows in the customer's ledger.
Can I track customer payments by stage?
Record advances as receipts against the customer ledger and raise invoices as each stage completes. The Customer Outstanding Report shows exactly how much each customer owes and at what stage, so your team can follow up after commissioning without guessing.
Every kilowatt costed, every serial on record
Book a demo and we will set up a sample 5 kW project: quotation with kWp formula, material challan, invoice with serials and an AMC as a recurring invoice.
