How to design solar layouts online?
Design a solar layout online by entering the site address, roof type and monthly electricity bill into a browser-based design engine — no CAD install needed.
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The SolvSolar Solar Encyclopedia is a searchable reference of 47 engineer-written answers on solar panels, inverters, batteries, EPC execution, subsidies and DISCOM net-metering rules.
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Last reviewed: October 2026
Recommended system
11.88 kW
Annual savings
₹1,20,166
47 answers
Design a solar layout online by entering the site address, roof type and monthly electricity bill into a browser-based design engine — no CAD install needed.
Read the full answerPayback period is turnkey system cost divided by annual electricity savings, giving the number of years until solar pays for itself.
Read the full answerYes — you can generate a complete solar proposal inside WhatsApp.
Read the full answerYes — SolvSolar charges $0 per seat, so solar design software is free to staff.
Read the full answerTopCon is more efficient than Mono PERC.
Read the full answerA 5 kW solar system needs about 10 panels of 540 Wp, or 13 panels of 400 Wp.
Read the full answerBifacial gain is the extra energy a double-sided module produces from light reflected onto its rear face.
Read the full answerPlan for 80-100 sq ft per kW of shade-free roof area.
Read the full answerOn-grid inverters export surplus power to the utility and shut down when the grid fails; off-grid inverters run entirely on batteries and work without any grid connection; hybrid inverters do both.
Read the full answerChoose a string inverter for uniform, unshaded roofs and microinverters for complex or partly shaded ones.
Read the full answerDesign for a DC/AC ratio of 1.1–1.3 in most rooftop systems.
Read the full answerNo — a battery is optional and only worth it if you need outage backup, face poor export rates, or pay high time-of-use peak tariffs.
Read the full answerRooftop solar typically pays back in 3–6 years in high-tariff, high-irradiance markets and 6–9 years in lower-irradiance ones.
Read the full answerCalculate annual solar savings as system size in kW multiplied by effective annual yield in kWh/kWp, multiplied by your electricity unit rate.
Read the full answerIndia's PM Surya Ghar scheme pays up to ₹78,000 in central assistance for a 3 kW residential system.
Read the full answerYes — solar is usually worth it for commercial buildings, with typical payback of 3–4 years.
Read the full answerSolar panels degrade roughly 0.4–0.55% per year after an initial 1–2% drop in the first year.
Read the full answerPhysical installation of a 3–10 kW residential rooftop system takes 1–3 days.
Read the full answerA solar proposal should list module, inverter, structure and workmanship warranties separately.
Read the full answerSolar needs very little maintenance — mainly panel cleaning and an annual electrical inspection.
Read the full answerA turnkey solar EPC scope covers everything from survey to handover: site survey, structural and electrical design, supply of modules, inverters, mounting structure, cables, protection devices and earthing, plus civil work, installation, testing and commissioning.
Read the full answerA 5–10 kW residential rooftop EPC project takes 7–15 working days on site, and 100 kW-plus commercial projects run 4–10 weeks.
Read the full answerBefore mounting, verify that the slab or purlins carry the dead load plus wind uplift, that waterproofing is intact, that parapets or water tanks will not shade the array, and that there is safe access for cleaning.
Read the full answerIn most turnkey contracts the EPC contractor handles liaisoning: filing the utility application, coordinating the inspection and installing the bi-directional meter.
Read the full answerLFP (LiFePO4) is the better choice for almost all solar storage today.
Read the full answerSize a backup battery by listing the loads you must keep alive, multiplying by the hours of autonomy you need, then dividing by usable depth of discharge and inverter efficiency.
Read the full answerUsually no — a battery rarely improves payback on its own.
Read the full answerRound-trip efficiency is the share of energy put into a battery that comes back out again.
Read the full answerIndian residential consumers apply on the national rooftop portal, choose an empanelled vendor, and receive the central financial assistance directly in their bank account after inspection and net-meter installation.
Read the full answerIndian commercial and industrial owners can claim accelerated depreciation on a solar asset, writing off a large share of its cost in the early years and cutting taxable income.
Read the full answerThe 30% residential credit (§25D) ended for systems placed in service after Dec 31, 2025.
Read the full answerNo — show subsidies as a separate line, not folded into the headline price.
Read the full answerNet metering credits exported units 1:1 against consumption, gross metering sells all generation to the utility at a fixed feed-in tariff, and net billing pays for surplus exports at a rate below the retail tariff.
Read the full answerYes — most Indian DISCOMs cap rooftop solar capacity at the consumer's sanctioned load, and many also cap total penetration on a distribution transformer or feeder.
Read the full answerA DISCOM rooftop application typically needs the latest electricity bill, consumer identity proof, roof ownership documents or an NOC, a single-line diagram, module and inverter datasheets with test certificates, an earthing layout and the empanelled vendor declaration.
Read the full answerGrid-tied solar must include anti-islanding protection, over- and under-voltage and frequency trip settings, DC and AC surge protection, an AC isolator the utility can access, and earthing to the applicable national standard.
Read the full answerTechnical feasibility approval for net metering typically lapses after 3–6 months if the system is not commissioned, and the application must then be refiled from scratch.
Read the full answerA realistic performance ratio for a well-designed rooftop system is 0.75–0.82 after temperature, soiling, mismatch, cable and inverter losses.
Read the full answerSoiling costs 3–8% of annual yield at dusty urban and industrial sites if panels are never cleaned, and can exceed that near construction or cement works.
Read the full answerA solar O&M contract should cover scheduled cleaning, thermal inspection of joints and combiner boxes, inverter firmware updates and fault handling, string IV curve checks, and monthly generation reporting against a guaranteed performance ratio.
Read the full answerDetect underperformance by comparing actual specific yield in kWh/kWp/day against the design irradiance baseline every week.
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Read the full answerThey are estimates based on the bill, tariff, yield and shading assumptions shown on each proposal.
Read the full answerThe 30% residential credit (§25D) ended for systems placed in service after Dec 31, 2025.
Read the full answerThird-party-owned systems may qualify under §48E, subject to deadlines.
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