Solar Installation Quotation Format

What a solar quotation must explain

• System size and type: total capacity in kWp, and whether it is on-grid, off-grid or hybrid. On-grid systems need net metering; off-grid and hybrid need batteries.
• Panels: wattage per panel, number of panels, technology (mono PERC, TOPCon, bifacial), brand, and whether they are DCR panels if the customer wants the government subsidy.
• Inverter: capacity, brand, phase (single or three phase) and warranty.
• Mounting structure: GI or aluminium, height of the elevated structure, and whether it is designed for the local wind speed.
• Balance of system: DC and AC cables, ACDB and DCDB with surge protection, earthing and lightning arrester.
• Net metering and approvals: who handles the DISCOM application, meter change and inspection, and whether the fee is included.
• Generation and savings: an estimated units per day or per year, and what that means for the electricity bill.
• Subsidy: what subsidy the customer may get and how it is paid. Keep it separate from your price.
• Warranty and service: panel product and performance warranty, inverter warranty, workmanship warranty, and any free cleaning or service visits.

Show subsidy separately, not as a discount

Under the PM Surya Ghar Muft Bijli Yojana for homes, the central subsidy is credited to the customer's bank account after the system is installed, inspected and commissioned. It is not something the installer deducts from the bill. If you reduce your quotation by the subsidy amount, the customer expects to pay that lower figure upfront, and you end up in an argument at handover.

The clean way is to show the full system price, then a separate note: "Expected central subsidy for 3 kW residential: up to Rs. 78,000, credited by the government to your account after commissioning. Effective cost after subsidy: Rs. X." Subsidy amounts and rules change, so ask the customer to check the national portal and mention that the subsidy needs DCR panels and a registered vendor.

Generation estimate: keep it honest

Customers buy solar for the bill saving, so they will ask how many units the system makes. In most of India, a well-placed rooftop system produces roughly 4 units per kWp per day on average across the year, more in summer and less in the monsoon. A 3.27 kWp system therefore gives about 12 to 14 units a day, or around 4,000 to 4,700 units a year, depending on location, shading and orientation.

Write the estimate as a range, mention shading if there is any, and avoid promising a "zero bill". Fixed charges on the electricity bill continue even with solar. An honest estimate protects your reputation when the customer compares bills six months later.

GST on solar: the 70:30 rule for combined contracts

When you supply the solar system and install it under one contract, GST is usually not worked out line by line. Under the GST rules for solar power generating systems supplied with installation, 70% of the total contract value is treated as goods and 30% as services. The goods part is taxed at 5% and the services part at 18%. That works out to an effective rate of about 8.9% on the whole contract (70% x 5% + 30% x 18% = 3.5% + 5.4%).

A simple worked example: a rooftop system is quoted at Rs. 2,00,000 before tax for supply plus installation. The goods portion is 70%, or Rs. 1,40,000, and GST at 5% on it is Rs. 7,000. The services portion is 30%, or Rs. 60,000, and GST at 18% on it is Rs. 10,800. Total GST is Rs. 17,800, which is 8.9% of Rs. 2,00,000, and the customer pays Rs. 2,17,800.

Show this split clearly in the totals of your quotation, as in the sample above, so the customer understands why the GST is not a single round rate. If you only supply panels without installation, or only do installation for material the customer bought, the 70:30 split does not apply in the same way. GST rates on solar have changed more than once in recent years, so confirm the current treatment with your accountant before you quote.

Payment terms that work for solar

Solar jobs involve a large material purchase before installation, so stage-wise payment is normal. A common pattern is an advance at order, a major payment when material reaches the site, and the balance after installation, with a small part held until net meter installation if the customer insists. Write the stages and percentages in the quotation so there are no doubts later.

Preparing solar quotations faster

Most residential solar quotations differ only in system size: the number of panels, the inverter rating and the structure. In Quotely Pro you save your panels, inverters and BOS items with your rates, copy a previous 3 kW quotation to make a 5 kW one, change the quantities, and download a branded PDF to send on WhatsApp. When a customer pays the booking amount, you can give an advance receipt from the same app. After commissioning, issue a warranty certificate listing the panels and inverter with their warranty periods and expiry dates, and see in Reports when each warranty ends so you can offer a cleaning or maintenance contract.

For the wiring side of a solar job, see the electrical work quotation format. For the general layout of any quotation, see the quotation format checklist.

Frequently asked questions