Indian EPCs shopping for solar design software in 2026 face a confusing landscape: six or seven tools that all claim to do “everything,” a wide spread of license costs from free to ₹5L per year, and almost no guidance on which tool is actually accepted by DISCOM, CEIG, IREDA, and SECI evaluators. Rohan — the founder scaling an India C&I EPC past ₹5 Cr/year in revenue — needs a practical tool-stack answer: which software for which deliverable, what it costs, and whether it will pass the regulatory and bankability tests that Indian projects face.
Direct answer. The working Indian solar engineer’s tool stack in 2026 is: PVsyst for bankable energy yield, AutoCAD (with PVCase or manual drafting) for IFC drawings and DISCOM/CEIG submissions, Helioscope for fast bid-stage 3D layouts, STAAD Pro for structural calculations, and HOMER Pro for hybrid or off-grid dispatch modeling. No single tool does all of this — the stack concept is the answer. The total annual license cost for this five-tool stack is approximately ₹3.5L–5.5L per designer, compared to ₹15–22L/year fully-loaded cost of a single in-house designer.
This buyer’s guide is written for Rohan — the Indian C&I EPC founder who needs to make intelligent software investments that let a small design team punch above their headcount. The guide covers what each tool does, what it costs in Indian rupees, which deliverables it produces, and which regulatory authorities in India accept its output.
Why Indian Solar Design Requires a Multi-Tool Stack
Indian solar projects face a more complex regulatory submission environment than most other markets. A typical 500 kW rooftop project requires: a 3D layout for the sales proposal (Helioscope), a PVsyst yield report for lender or DISCOM submission, an AutoCAD GA drawing for DISCOM application, an AutoCAD SLD for CEIG approval, and a STAAD Pro structural report for the structural engineer’s stamp.
No single tool produces all of these. The designer who tries to use one tool for everything — producing a DISCOM drawing from a Helioscope screenshot, for example — creates deliverables that are rejected by regulators and that create rework cost greater than the license cost of the correct tool.
Definition. The "solar design stack" refers to the combination of software tools that a design team uses across the full project lifecycle — from sales proposal (3D layout) through bid-stage yield study, IFC drawing production, structural analysis, and regulatory submission. Each tool in the stack is optimized for its specific output; no single tool replaces the stack.
₹3.5L
Minimum annual stack cost (3 tools)
Heaven Designs analysis, 2025
₹18–22L
Fully-loaded in-house designer cost
Heaven Designs internal, 2025
62%
Indian EPCs using AutoCAD for IFC
Bridge to India software survey, 2024
5
Tools in the complete Indian solar design stack
Heaven Designs stack audit, 2025
Tool 1 — PVsyst: The Non-Negotiable for Yield
PVsyst is the bankability anchor of any Indian solar design stack. Without PVsyst (or a PVsyst report from a qualified consultant), no IREDA, PFC, or SECI-appointed IE will accept your energy yield study. There is no substitute.
What PVsyst does: Simulates the annual energy output of a solar array using site-specific irradiance data, hardware-specific loss modeling, and a validated radiation transfer algorithm. Produces P50/P90/P99 yield reports accepted by lenders, IEs, and DFI project evaluators. According to PVsyst’s published validation data, the software achieves within ±2% of measured annual energy for grid-connected systems when irradiance data quality is adequate — the primary reason it has become the global standard for bankable yield simulation.
Indian regulatory acceptance: Accepted by IREDA, PFC, SBI, REC, and all major SECI-appointed IEs. MNRE guidelines for solar project DPRs reference PVsyst or an equivalent certified tool — in practice, PVsyst is the standard.
License cost in India (2025): Approximately ₹1.1L–1.2L/year (€1,250/year + GST + currency conversion). A single license can be used by multiple users sequentially; floating network licenses for concurrent use cost approximately 2.5× the base price.
Learning curve: 4–8 weeks to produce a basic bankable report; 3–6 months to master P90 uncertainty calculations, bifacial modeling, and tracker simulation for IE-level quality.
Field tip. For most Indian EPCs doing projects below 1 MW, the PVsyst license cost is justified only if you are doing 8+ bankable yield reports per year — below that frequency, outsourcing the PVsyst report to a specialist consultant like Heaven Designs is more economical than maintaining an in-house license and the expertise to use it correctly.
Tool 2 — AutoCAD Electrical / AutoCAD LT: The Regulatory Drawing Standard
AutoCAD — in its Electrical or LT variant — is the standard for every DISCOM, CEIG, and MNRE-format drawing in India. CEIG offices across every Indian state accept AutoCAD DWG format; most reject PDF-only submissions for engineering drawings.
What AutoCAD does for solar: Produces dimensioned GA drawings, SLDs, key-plan drawings, earthing layouts, and cable routing drawings — all in the DWG format required by CEIG and DISCOM offices.
AutoCAD Electrical vs AutoCAD LT: AutoCAD Electrical adds intelligent circuit design, automatic report generation (cable schedules, wire numbering), and panel layout tools. For solar SLD production, AutoCAD Electrical reduces drawing time by 30–40% compared to basic AutoCAD LT because components can be inserted from a smart library rather than drawn from scratch. AutoCAD LT is sufficient for layout drawings and basic SLDs; AutoCAD Electrical is recommended for high-volume SLD production.
License cost in India (2025): AutoCAD LT: approximately ₹43,000–48,000/year. AutoCAD Electrical (included in the AutoCAD full version): approximately ₹1.15L–1.35L/year. AutoCAD is available at a discounted rate for students and startups — check Autodesk’s India startup program for early-stage EPCs.
DISCOM acceptance: 100% — DWG format is the de facto standard for DISCOM application drawings across all Indian states. See the DISCOM net-metering guide for state-specific drawing format requirements.
Tool 3 — Helioscope: The Bid-Stage Speed Tool
Helioscope is the fastest path from a client’s site address to a 3D layout with a preliminary yield estimate. For C&I EPCs doing 20+ bids per month, Helioscope’s 2–4 hour turnaround for a bid-stage layout creates a measurable competitive advantage over firms that spend 2 days per bid in AutoCAD.
What Helioscope does: Browser-based 3D solar layout using Google Maps or satellite imagery as the base. Integrated shade analysis, preliminary yield simulation, and PDF proposal output. Module and inverter database maintained by Folsom Labs.
Indian regulatory acceptance: Helioscope PDF output is not accepted for CEIG or DISCOM submission — DWG is required. Helioscope is used for bid-stage proposals and sales visualizations in India; the design is then transferred to AutoCAD for regulatory submissions.
License cost in India (2025): Approximately ₹25,000–30,000/month (≈ $299/month) per user. Annual prepayment at approximately ₹2.5L–3L offers a discount over monthly billing.
Decision gate: Use Helioscope for the bid. Once the project is won, transition to AutoCAD + PVsyst for IFC and CEIG deliverables.
Tool 4 — STAAD Pro: The Structural Non-Negotiable
STAAD Pro (or its equivalent, SAP2000) is required for the structural engineering report that accompanies any solar project DPR, CEIG drawing, or IREDA submission. STAAD Pro is the software accepted by CEIG offices, structural engineers-of-record, and IEs for solar mounting structure analysis in India.
What STAAD Pro does: 3D structural analysis of solar mounting structures, pile foundations, and rooftop structural adequacy. Produces IS 875 Part 3 wind load calculations and IS 1893 seismic checks. The STAAD Pro report is the document that carries the structural engineer’s stamp.
License cost in India (2025): STAAD Pro: approximately ₹1.2L–1.8L/year. Structural engineers running the analysis often have existing licenses — EPCs who outsource structural design do not need to maintain this license themselves.
Who actually runs it: In most Indian EPCs below 20 MW/year project volume, structural analysis is outsourced to a specialist structural engineer or a firm like Heaven Designs rather than run in-house. The structural report is a deliverable, not an in-house activity.
Tool 5 — HOMER Pro: For Hybrid and Off-Grid Projects
HOMER Pro is the dispatch modeling tool for projects with solar + battery + diesel or grid complexity. For standard grid-connected Indian C&I projects without BESS, HOMER Pro is not part of the stack. For projects with behind-the-meter BESS, rooftop solar + hybrid inverter, or off-grid/island-mode designs, HOMER Pro becomes essential.
License cost in India (2025): Approximately ₹2.9L–3.1L/year ($3,495/year) per user. For EPCs doing fewer than 3 hybrid simulations per year, purchasing simulation as a service from Heaven Designs is more cost-effective than maintaining an in-house license.
The India Solar Design Stack Cost Matrix
| Tool | Annual Cost | Required for | Who Needs In-House |
|---|---|---|---|
| PVsyst | ₹1.1L–1.2L | IREDA/PFC/SECI bankable yield | EPCs with ≥ 8 bankable reports/year |
| AutoCAD LT | ₹43K–48K | DISCOM/CEIG drawings | All EPCs submitting regulatory drawings |
| AutoCAD Electrical | ₹1.15L–1.35L | High-volume SLD production | EPCs with ≥ 12 IFC SLD sets/year |
| Helioscope Pro | ₹2.5L–3L | Bid-stage 3D layouts | EPCs with ≥ 10 bids/month |
| STAAD Pro | ₹1.2L–1.8L | Structural reports | Structural engineering teams only |
| PVCase | ₹2.5L–5L | Sloped ground-mount IFC | EPCs with frequent ground-mount work |
| HOMER Pro | ₹2.9L–3.1L | Hybrid/off-grid dispatch | Hybrid specialists only |
The India Solar Designer Stack Selection Framework
The India Solar Designer Stack Selection Framework helps EPCs decide which tools to license in-house and which to outsource, based on project volume, project type, and design team size.
Count Your Annual Output by Deliverable Type
Count: how many bid-stage layouts per month? How many CEIG/DISCOM drawing sets per month? How many bankable PVsyst reports per year? How many structural reports per year? This inventory determines which tools pay for themselves in-house and which are more economical as outsourced services.
Apply the Break-Even Test
For each tool, calculate: (license cost + designer salary allocated to tool use) vs (per-unit outsource cost × annual volume). If in-house is cheaper, license it. If outsourcing is cheaper, use a specialist. Example: PVsyst bankable report costs approximately ₹18,000–40,000 to outsource to Heaven Designs. At ₹1.2L/year license + ₹5L/year designer time, in-house breaks even at 8 reports/year.
Build the Minimum Viable Stack First
Start with AutoCAD LT (₹43K–48K/year) + Helioscope (₹2.5L–3L/year). These two tools cover bid-stage layouts and DISCOM drawing production — the two highest-frequency deliverable types for most C&I EPCs. Add PVsyst when your bankable yield report volume justifies it. Add STAAD Pro or PVCase when structural and ground-mount volume justifies it.
Outsource the Tail
The tools that do not break even in-house — PVsyst for EPCs with < 8 reports/year, HOMER Pro for EPCs with < 3 hybrid projects/year, STAAD Pro for EPCs who do not employ a structural engineer — should be outsourced. The outsource cost is predictable, the quality is consistent, and the tool-ownership risk (license lapses, software updates, user upskilling) sits with the specialist, not the EPC.
Review the Stack Annually
As your EPC grows, the break-even thresholds shift. An EPC doing 5 bankable reports/year at ₹18,000/report outsource cost (total: ₹90,000/year) should re-evaluate when volume reaches 7 reports/year — the break-even point where in-house becomes cheaper. Review the stack every 12 months against actual volume and outsource costs.
Stack Recommendation by EPC Profile
| EPC Profile | In-House Tool Stack | Outsource |
|---|---|---|
| Early-stage C&I EPC (< ₹2 Cr/year revenue) | AutoCAD LT | PVsyst, Helioscope, Structural |
| Mid-stage C&I EPC (₹2–10 Cr/year) | AutoCAD Electrical + Helioscope | PVsyst, Structural, HOMER |
| Established C&I EPC (₹10–50 Cr/year) | AutoCAD Electrical + Helioscope + PVsyst | Structural, HOMER, PVCase (unless ground-mount heavy) |
| Utility-scale developer (> 50 Cr/year) | Full stack: AutoCAD + PVsyst + Helioscope + PVCase + STAAD Pro | HOMER (unless hybrid specialist) |
Free and Low-Cost Alternatives — Where They Fit (and Where They Do Not)
Several free or low-cost solar design tools circulate in the Indian market. They serve specific purposes but are not substitutes for the professional stack:
- PVGIS (free, EU Commission): Useful for quick irradiance checks. Not accepted by IREDA IEs as a standalone yield tool.
- SAM — System Advisor Model (free, NREL): Accepted by some lenders as a PVsyst alternative, particularly for US projects. In India, IREDA IEs prefer PVsyst. SAM is appropriate for feasibility studies.
- SketchUp (free version): Useful for 3D roof model visualization for sales proposals. Not suitable for IFC drawings or CEIG submission.
- Excel/Google Sheets: Many Indian designers run string sizing, cable sizing, and BOQ calculations in Excel. This is acceptable for the calculation layer but the outputs must be formatted into AutoCAD drawings for regulatory submission.
Watch out. Using a free PVGIS-based yield estimate as the energy production figure in an IREDA loan application is a common and costly error. IREDA's LDED team will require a PVsyst report — and the time spent rerunning the simulation (2–4 weeks including IE review) occurs while the interest meter on your pre-disbursement bridge loan is running.
Comparison — In-House Stack vs Outsourced Design Model
| Factor | In-House Stack (3–5 tools) | Outsourced to Heaven Designs |
|---|---|---|
| Annual tool cost | ₹3.5L–7L | Included in per-project pricing |
| Designer training time | 3–9 months per tool | Not the EPC’s cost |
| Tool version management | EPC’s responsibility | Managed by HD |
| Quality consistency | Varies with designer skill | Consistent — 50+ engineer bench |
| Scalability in bid peaks | Limited by in-house headcount | On-demand |
| IREDA/IE acceptance | Depends on internal quality | HD reports accepted by major IEs |
| Turnaround (PVsyst report) | 5–10 days (in-house) | 5–7 days (outsourced to HD) |
According to Bridge to India’s 2025 India Solar Annual Report, India’s installed solar capacity is expected to reach 280 GW by end-2026, driving significant growth in EPC design throughput requirements. EPCs who build a software stack that scales with project volume — and outsource the tail of low-frequency, high-complexity tools — will outpace competitors who either under-invest in tools or over-invest in in-house headcount.
The IREDA project finance guidelines explicitly require that energy yield simulations submitted as part of loan applications use recognized, validated simulation software. PVsyst is the only yield simulation tool named in IREDA’s lender technical advisory documentation as meeting this requirement — making it a non-optional element of the India solar design stack for any project seeking institutional financing.
See what the full Heaven Designs stack produces
Download a sample pack including a PVsyst yield report, AutoCAD SLD, and Helioscope bid-stage layout from a recent 2 MW C&I project — all produced using the Heaven Designs multi-tool stack.
Get the sample pack →How Heaven Designs Helps
Heaven Designs runs the full five-tool stack in-house — PVsyst, AutoCAD Electrical, Helioscope, STAAD Pro, and HOMER Pro — for EPCs who want the output of the stack without maintaining it themselves. The model is simple: you provide the site data, we deliver the drawings.
- Solar Rooftop Detailed Engineering Design — Full IFC package: PVsyst yield, AutoCAD SLD and GA, structural BOQ
- Electrical CEIG Drawings — AutoCAD Electrical-produced CEIG-ready SLDs for DISCOM and CEIG submission
- Bankable PVsyst Reports — IE-accepted P50/P90/P99 yield studies for IREDA/PFC/SECI
- Solar 3D Pre-Design — Helioscope-based bid-stage layouts with preliminary yield in 48 hours
- STAAD Pro Report & Calculations — Structural analysis reports for mounting systems, CEIG submissions, and IREDA DPRs
- Download a sample deliverable — See the stack in action on a real project
Contact us to discuss a monthly retainer that covers your bid-stage and IFC design volumes at a fixed per-MW rate.
FAQ
Which solar design software is accepted by CEIG in India?
CEIG offices across Indian states accept drawings in AutoCAD DWG format. The drawing must be signed by a licensed electrical engineer or CEIG-registered contractor. PVsyst, Helioscope, and HOMER Pro produce outputs that may inform the CEIG drawing but are not themselves submitted to CEIG. The AutoCAD SLD — drafted to CEIG specifications and signed by the responsible engineer — is the CEIG-accepted document. See the CEIG drawing approval guide for state-specific requirements.
Is PVsyst mandatory for IREDA project finance?
PVsyst is not named by name in IREDA’s project finance guidelines, but IREDA’s LDED team effectively requires it. The IE appointed by IREDA will request a bankable energy yield study that shows P50/P90/P99 exceedance levels with documented loss assumptions — and in practice, PVsyst is the tool that produces this format. SAM (NREL System Advisor Model) has been accepted as an alternative by some IREDA IEs, but PVsyst remains the standard. See the LDED checklist for exact IREDA documentation requirements.
What is the best free solar design software for Indian EPCs?
For irradiance checking, PVGIS (free, EU Commission) and NREL’s SAM (free) provide acceptable feasibility-level yield estimates. For basic SLD drafting, LibreCAD (free) can produce drawings but lacks the intelligent symbols and panel libraries of AutoCAD Electrical. For bid-stage layouts, no free tool matches Helioscope’s speed and visualization quality — though the Google Sunroof API provides rough rooftop area estimates at zero cost. None of these free tools produce IREDA-bankable output or CEIG-acceptable DWG drawings without additional work.
How long does it take to learn PVsyst well enough for IREDA submissions?
A designer with no prior PVsyst experience typically reaches “adequate” proficiency — able to produce a basic P50 yield report — in 4–6 weeks of daily use. Reaching “bankable” proficiency — producing a report that passes an IE’s technical review without major comments — takes 3–6 months of working on real projects with feedback from an experienced reviewer. For EPCs who need bankable PVsyst quality immediately, outsourcing to Heaven Designs while building in-house capability is the most effective transition strategy.
Can a designer use both Helioscope and AutoCAD on the same project?
Most efficient Indian design workflows use both Helioscope and AutoCAD on the same project. Helioscope provides the initial 3D layout for the sales proposal and bid document — fast to produce and easy to present to clients. Once the project is won, the designer transfers the module count, orientation, and row configuration to AutoCAD, where the CEIG and DISCOM drawings are produced to the required format and signature standards. The solar engineering workflow guide describes this dual-tool workflow in detail.
What is PVCase and do Indian EPCs need it?
PVCase is an AutoCAD plug-in that speeds up ground-mount solar layout design by automating row placement, shade angle calculations, and GCR optimization within the AutoCAD environment. It is most valuable for EPCs doing frequent ground-mount projects on sloped terrain, where manual AutoCAD layout is time-consuming and prone to error. For EPCs focused on rooftop C&I, PVCase is not necessary — Helioscope and basic AutoCAD are sufficient. See the Helioscope vs PVCase comparison for a detailed analysis.
Where can Indian designers get PVsyst training?
PVsyst training is available through several channels: PVsyst’s own online training modules (in English and French), TERI (The Energy and Resources Institute) in-person workshops, and several private training providers in Surat, Ahmedabad, and Pune. Heaven Designs’ engineers have completed PVsyst’s own certified training program and regularly produce IE-accepted reports for IREDA and SECI projects — the internal training program developed at Heaven Designs focuses specifically on the loss-assumption justification and P90 uncertainty methodology that Indian IEs scrutinize most closely. According to MNRE’s solar project guidelines, energy yield simulations for government-funded solar projects must be conducted by qualified engineers using recognized simulation tools.
