Question 1

How to design solar layouts online?

Accepted Answer

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. SolvSolar's 2D/3D array engine auto-places modules on flat roofs, metal sheds or ground mounts, locks the panel count to the bill of materials, and returns a shareable proposal in about 45 seconds.

Question 2

What is payback period calculation?

Accepted Answer

Payback period is turnkey system cost divided by annual electricity savings, giving the number of years until solar pays for itself. Annual savings equal system size in kW multiplied by effective yield in kWh/kWp after shade losses, multiplied by your electricity unit rate. Typical rooftop payback runs 3–6 years in high-tariff markets and 6–9 years elsewhere.

Question 3

Can I generate solar proposals on WhatsApp?

Accepted Answer

Yes — you can generate a complete solar proposal inside WhatsApp. SolvSolar runs native WhatsApp and Telegram bots: a homeowner sends their address and monthly bill, and the bot replies with a hosted proposal URL covering system size in kW, 25-year savings and a financing link. The whole exchange takes under a minute with no manual work from the installer.

Question 4

Is there free solar design software for installers?

Accepted Answer

Yes — SolvSolar charges $0 per seat, so solar design software is free to staff. You add unlimited team members at no cost and pay only for the kilowatts you actually design, drawn from a 100 kW free trial, then a monthly subscription quota, then a pay-per-kW wallet. There are no per-user licences to renew.

Question 5

Mono PERC vs TopCon — which is more efficient?

Accepted Answer

TopCon is more efficient than Mono PERC. Mono PERC modules typically deliver 20–21% cell efficiency, while TopCon (tunnel oxide passivated contact) reaches 22–23%, with a lower temperature coefficient and better low-light performance. TopCon costs slightly more per watt but yields more kWh per kWp over a 25-year life, and the gap widens in hot climates where PERC derates faster.

Question 6

How many panels do I need for a 5 kW system?

Accepted Answer

A 5 kW solar system needs about 10 panels of 540 Wp, or 13 panels of 400 Wp. The maths is simply 5,000 W divided by the module wattage, rounded up. Plan for roughly 350–400 sq ft of shade-free roof area, or more if the array is elevated on a structure with inter-row clearance.

Question 7

What is bifacial gain?

Accepted Answer

Bifacial gain is the extra energy a double-sided module produces from light reflected onto its rear face. It typically adds 5–15% to annual generation, depending on ground albedo, mounting height and tilt. Elevated or ballasted structures over white membrane, concrete or light sand see the highest gain; dark or heavily shaded ground sees almost none.

Question 8

How much roof area does 1 kW of solar need?

Accepted Answer

One kilowatt of rooftop solar needs about 65–80 sq ft (6–7.5 m²) of shade-free area. Elevated or ground-mount layouts need 100–120 sq ft per kW because inter-row spacing must avoid self-shading. Higher-efficiency modules of 550 Wp and above pull the requirement toward the lower end of each range.

Question 9

Difference between On-Grid, Off-Grid and Hybrid inverters?

Accepted Answer

On-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. Hybrids export to the grid in normal operation and switch to a battery bank during outages, which costs more upfront but removes the need for diesel backup.

Question 10

String inverter or microinverter?

Accepted Answer

Choose a string inverter for uniform, unshaded roofs and microinverters for complex or partly shaded ones. String inverters cost less per watt and are simpler to service. Microinverters and DC optimisers perform panel-level MPPT, recovering more energy on multi-orientation roofs, and they simplify rapid-shutdown compliance in markets where that code applies.

Question 11

What DC/AC ratio should I design for?

Accepted Answer

Design for a DC/AC ratio of 1.1–1.3 in most rooftop systems. Oversizing the array relative to inverter capacity flattens the generation curve and raises annual yield, especially in cloudy or high-latitude sites. Above roughly 1.35, midday clipping losses start to outweigh the morning and evening gains, so the extra modules stop paying for themselves.

Question 12

Do I need a battery with rooftop solar?

Accepted Answer

No — 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. Where net metering credits exports 1:1, a grid-tied system without storage gives the fastest payback. Batteries add cost per kWh of usable capacity and buy resilience rather than ROI.

Question 13

What is the solar payback time?

Accepted Answer

Rooftop solar typically pays back in 3–6 years in high-tariff, high-irradiance markets and 6–9 years in lower-irradiance ones. Commercial and industrial systems usually sit at the fast end because unit rates are higher and daytime load matches generation. Modules keep producing for 25 years or more, so most of the asset life is effectively free energy.

Question 14

How to calculate solar savings?

Accepted Answer

Calculate annual solar savings as system size in kW multiplied by effective annual yield in kWh/kWp, multiplied by your electricity unit rate. Subtract any fixed charges that stay on the bill regardless of consumption. Project the figure across 25 years using a 2–5% annual tariff escalation and a 0.5% yearly panel degradation rate for a realistic lifetime number.

Question 15

What subsidies are available for rooftop solar?

Accepted Answer

Rooftop solar subsidies vary by country: India's PM Surya Ghar scheme pays up to ₹78,000 in central assistance for a 3 kW residential system, and the United States offers a 30% federal Investment Tax Credit. Many EU states, the UK, Australia and the UAE run feed-in tariffs, VAT relief or rebates. Commercial systems are usually excluded from residential schemes.

Question 16

Is solar worth it for commercial buildings?

Accepted Answer

Yes — solar is usually worth it for commercial buildings, with typical payback of 3–4 years. Commercial tariffs are higher than residential ones, daytime occupancy matches the solar generation curve almost exactly, and accelerated depreciation plus tax credits shorten payback further. After that the system delivers 20-plus years of near-free daytime electricity.

Question 17

What is the standard degradation rate of solar panels?

Accepted Answer

Solar panels degrade roughly 0.4–0.55% per year after an initial 1–2% drop in the first year. That means a Tier-1 module still delivers about 87–92% of its rated output at year 25, which is what a linear performance warranty guarantees. TopCon and heterojunction cells sit at the slower end; older polycrystalline modules degrade faster.

Question 18

How long does a rooftop solar installation take?

Accepted Answer

Physical installation of a 3–10 kW residential rooftop system takes 1–3 days. The longer wait is paperwork: utility interconnection, net-metering approval and inspection typically add 2–8 weeks depending on the DISCOM or utility. Commercial projects above 100 kW usually run 4–10 weeks on site plus the same approval cycle.

Question 19

What warranties should a solar proposal include?

Accepted Answer

A solar proposal should list module, inverter, structure and workmanship warranties separately. Expect 12–15 years product and 25–30 years linear performance warranty on modules, 5–12 years on inverters (often extendable), 10 years on mounting structures, and 1–5 years of installer workmanship cover. Anything vaguer than that is a red flag worth challenging before signing.

Question 20

How much maintenance does solar need?

Accepted Answer

Solar needs very little maintenance — mainly panel cleaning and an annual electrical inspection. Clean every 1–3 months in dusty regions and less often in rainy climates; skipping it can cost 3–8% of annual yield to soiling. Budget 0.5–1% of system value per year for O&M, and rely on remote monitoring alerts to catch faults early.

Capability	Legacy CAD tools	SolvSolar OS
Cost per seat	$99 – $250 / user / month	$0 / seat — pay per kW designed
Proposal turnaround	20 – 90 minutes of CAD work	45 seconds, end to end
Mobile speed	Desktop-first, heavy WebGL	Mobile-first PWA, sub-second loads
WhatsApp / Telegram	Not supported	Native WhatsApp + Telegram bots
DISCOM & net metering	US-centric presets	Global DISCOM & net-metering rulesets
Financing + e-signature	Bolted on or third-party	Built in, 1-click sign

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