How to select the best solar panel setup for your home
Are high electricity bills pushing you toward renewable energy?
Solar power lets homeowners lock in decades of clean, low-cost energy—and 2025 incentives make the switch easier than ever. This guide walks you through panel types (including the newest TOPCon and HJT n-type technologies), roof checks, system sizing and financing so you can pick the best solar for home with confidence.
Understanding the solar-energy basics
Photovoltaic (PV) cells—mostly silicon—convert sunlight into direct current (DC).
A solar inverter then changes DC to alternating current (AC) so your appliances (and the grid) can use it. Panels wired on the roof (or a ground array) generate power; excess flows back to the grid through net-metering or into batteries for night-time use.
Types of solar panels: which one is right for you?
P-type options
Monocrystalline PERC
- Efficiency 15–22% • ₹80–₹120 /W • Temp-co −0.40%/°C
Polycrystalline
- Efficiency 13–18% • ₹70–₹90 /W • Temp-co −0.42%/°C
Thin-film
- Efficiency 10–13% • ₹50–₹80 /W • Temp-co −0.31%/°C (but needs more roof area)
N-type technologies: TOPCon vs HJT
| Parameter | Mono PERC | TOPCon | HJT |
|---|---|---|---|
| Initial capex (module fab) | \$31–38 mn /GW | \$38–46 mn /GW | \$69–75 mn /GW |
| Cell efficiency (lab) | 23.2–23.7% | 24.5–25.2% | 24.5–25.2% |
| Module efficiency (2025) | 20.0–21.5% | 22.0–23.0% | 22.0–23.0% |
| Bifaciality | 70–75% | 80–85% | 80–90% |
| Temperature coefficient | −0.35%/°C | −0.29%/°C | −0.24–−0.26%/°C |
| Degradation (yr 1 / annual) | 2% / 0.45% | 1% / 0.25% | 1% / 0.25% |
| PID / LID risk | High | Low | None |
2025 India street pricing
TOPCon ₹95–115 /W
HJT ₹110–135 /W
Expect TOPCon prices to match PERC by 2026; HJT ~10% higher until mass-production scales.
Quick selector – 2025 update
| Situation | Recommended tech | Why |
|---|---|---|
| Maximum power per m² | HJT | Highest efficiency, lowest temperature loss |
| High ROI at slight premium | TOPCon | +5–7% energy vs PERC, moderate cost bump |
| Budget-first retrofit | Polycrystalline | Lowest ₹/W, proven supply |
| Tight roof & conservative budget | Mono-PERC | Good efficiency, wide availability |
| Metal sheds / curved surfaces | Thin-film | Flexible, excellent high-heat tolerance |
What to check before you go solar
- Roof condition & orientation – South-facing roofs harvest the most sun; east/west still work. Roof must handle 10–15 kg/m² for 25 years.
- Clear surface area – Measure usable roof after chimneys, tanks and skylights.
- Shade analysis – Use Google Project Sunroof or a local audit to see yearly sun hours.
- Future load growth – Factor an EV charger or new AC when sizing the system.
Calculating your energy needs
1 — Review your bills
Add the last 12 months of kWh and divide by 12 to get your average monthly consumption.
2 — Convert to daily kWh
Divide the monthly figure by 30.
3 — Account for growth
Add expected load increases (EV, new appliances).
4 — Estimate system size
Use PVWatts or our ROI calculator to convert kWh to required kW for your city’s sun-hours.
Typical system sizes
| Home size | Monthly use | Recommended system |
|---|---|---|
| ≤1,000 ft² | ≤400 kWh | 3 kW |
| 1,000–2,000 ft² | 500–600 kWh | 5–6 kW |
| ≥2,000 ft² | ≥700 kWh | 7–10 kW |
Step-by-step sizing example
- Average use: 540 kWh/month
- Daily: 18 kWh
- Delhi sun hours: ≈5.5 h/day
- System: 18 ÷ 5.5 ≈ 3.3 kW
- Add 15% buffer: 3.3 × 1.15 ≈ 3.8 kW → 4 kW array
Installation and maintenance costs (Delhi 2025)
| Item | Cost (₹) |
|---|---|
| Hardware + labour | 65,000–80,000 / kW |
| PM Surya Ghar CFA (up to 3 kW) | −78,000 |
| Delhi GBI bonus | ₹3/kWh (≤3 kW) |
| Cleaning (annual) | ~2,000 |
| Inverter replacement (year 12–15) | 30,000–40,000 |
Choosing a solar installer
- Certification – MNRE-empanelled or NABCEP-style credentials.
- Reviews – Check Google & SolarReviews.
- Warranties – 25-year performance, 10-year product, 5-year workmanship minimum.
Warranty and degradation — 2025 benchmarks
| Tech | Guaranteed output after 25 yrs |
|---|---|
| Poly / Mono PERC | 80–82% |
| TOPCon | 87–88% |
| HJT | 89–90% |
Lower degradation = more lifetime kWh and higher resale value.
Frequently asked questions
What size solar system do I need for a 2,000 sq ft house?
Most Indian homes that size use 500–600 kWh a month. A 5–6 kW system usually covers 80–100% of demand.
TOPCon vs HJT: which is better for Delhi heat?
Both beat PERC, but HJT edges ahead with a −0.25%/°C temp-co and higher bifacial gains. ROI depends on module price gap.
Is paying extra for TOPCon worth it?
With an 8–12% price premium, TOPCon’s ~5% energy boost plus slower degradation typically pays back within five years.
Can I mix TOPCon panels with existing PERC panels?
Yes—just keep each tech on separate MPPT strings or micro-inverters to avoid mismatch losses.
How long does it take to get my money back?
With 2025 subsidies and Delhi GBI, most systems pay back in three–five years; without incentives, five–seven years.
Do solar panels damage the roof?
Installed with proper flashing and chemical anchors, panels add only 10–15 kg/m² and actually shield the roof from UV and rain.
How much maintenance is required?
Rinse once a month in Delhi’s dry season and schedule an annual electrical inspection—usually under ₹2,000 a year.
Can I expand the system later?
Yes. Choose an inverter with spare DC input or add a micro-inverter string; your DISCOM will update the net-meter.
Internal resources
Last updated: 25 June 2025
Sources: PVEL Scorecard 2024; Trina Vertex S TOPCon datasheet Q1-2025; Meyer Burger HJT datasheet 2025; IEA PV price brief May 2025.