Rooftop Solar Planning: What DPRs and Quotes Really Tell You

Thinking of installing a rooftop solar (RTS) system?

Before you go ahead, take a closer look at two essential documents: the solar DPR and the solar panel quote. These aren’t just formalities. They define how your system will perform, what it will cost, and how soon you’ll start saving money.

If you skip the fine print, you may lose more than you gain. This blog will show you what to look for and what to avoid.

What Is a Solar DPR?

A Detailed Project Report (DPR) is the backbone of your solar project. It combines site insights, technical design, cost projections, and financial returns, all in one place.

A good solar DPR should cover:

• System capacity (kWp)
• Estimated energy generation per year
• Equipment list (panels, inverters, structures)
• Site conditions and shadow analysis
• Roof layout and load capacity
• Total system cost (CapEx)
• Projected ROI, IRR, and payback period

DPRs are usually prepared by the EPC company or a solar consultant. They guide major decisions, from vendor selection to loan approvals.

What Should a Solar Panel Quote Include?

A solar panel quote outlines what you're paying for and what you’re getting in return. It’s more than a price tag.

Your quote should clearly list:

• Cost per kWp
• Total RTS cost
• Detailed Bill of Materials
• Brands of key components
• Warranties (panel, inverter, workmanship)
• AMC (Annual Maintenance Contract) details
• Payment terms and timelines

Don’t just compare totals. A lower quote might exclude critical services like net metering or AMC. Break down the cost before making a decision.

Key Technical Details That Matter

Not all components are equal. The quality of materials used impacts generation, maintenance, and lifespan. Here's what to focus on:

Panels

Go for Tier-1 monocrystalline panels, 500 Wp or higher. They should carry a 25-year performance warranty.

Inverters

Choose a trusted brand with at least a 5-year warranty. For complex roofs, ask for multi-MPPT models. IoT-enabled monitoring is a bonus.

Cables and Connectors

Insist on quality. Weak cabling leads to efficiency losses and future costs.

Layout and Shadow Analysis

The solar DPR should include a detailed layout with shadow mapping. Even partial shade on one panel can reduce the output of the entire string.

Understanding Cost and Long-Term Savings

Your upfront RTS cost depends on:

• System size
• Component specs
• Roof type and accessibility
• Mounting or civil work needed

On average, 1 kWp of solar generates around 4 units/day in India. Over a year, that's about 1500 kWh. For a 100 kWp plant, that’s 1.5 lakh units, translating to ₹15 lakh in annual savings at ₹10/unit.

But performance degrades by 0.5% each year. A reliable solar DPR factors this into your long-term savings.

Payback Period and ROI

The payback period tells you how long it will take to recover your investment from your energy savings.

Say your RTS cost is ₹45 lakh. If you're saving ₹15 lakh/year, your payback is just 3 years.

But this number changes based on:

• Your current electricity rate
• Net metering policies
• Seasonal variations in generation
• System efficiency and downtime

A well-designed system can offer a yearly ROI of 18–25%. Check if the DPR includes calculations for both ROI and IRR (Internal Rate of Return).

How to Compare Solar Quotes the Right Way

Don’t just go with the cheapest quote. Compare the full picture. Ask each vendor to provide details for the following:

• Total RTS cost – Final number, including all taxes and fees
• Energy output – Annual kWh generation expected
• Panel brand and warranty – Tier-1 panels with a 25-year warranty?
• Inverter details – Is it suitable for your site and layout?
• AMC – Is post-installation service included? How often?
• Payback period – Years to recover your investment
• ROI – Projected return over 10–25 years

This checklist helps you evaluate proposals side by side. A well-priced system should balance quality, service, and returns.

Mistakes That Could Cost You

Many businesses make these errors when reviewing a quote:

• Choosing the lowest price without checking component quality
• Ignoring hidden charges (transport, CEIG, net metering)
• Overlooking AMC details or exclusions
• Skipping site visits and feasibility checks
• Assuming all warranties are equal
• Not confirming who handles DISCOM approvals and grid tie-up

Always ask for every inclusion in writing.

Final Thoughts

Installing rooftop solar is a smart business move when backed by the right plan.

A clear solar panel quote and a solid solar DPR help you make informed, long-term decisions. Don’t focus only on cost. Look at savings, service, and performance over time. Done right, you're securing 25 years of energy stability.

To support this transition, Svakarma offers SuryaKiran Loan, a rooftop solar loan for commercial and industrial buildings. It covers both purchase and installation, with flexible terms, quick approvals, and no upfront burden.

This is one way we help you lower energy costs, protect cash flow, and invest in a cleaner future.