Businesses, churches, schools, hospitals and farms usually pay higher tariffs than homes, so rooftop solar typically pays back in 3 to 5 years. They do not receive the household subsidy, but can buy outright, borrow on a term loan, or choose a zero-upfront RESCO model. Farms can use solar pumps under PM-KUSUM.
Why non-household solar pays well
Commercial and institutional tariffs are higher, and daytime-heavy loads use most of what the roof produces. A 50 kW system generates about 72,000 units a year; at ₹8 per unit that saves roughly ₹5.8 lakh a year.
Choose your funding model
| Model | Upfront | Best for |
|---|---|---|
| CAPEX (buy) | ₹45,000–55,000/kW | Organisations with funds or taxable income |
| Term loan | Margin money | Savings above the EMI |
| RESCO / OPEX | Zero | Trusts and institutions preferring no outlay |
Model the choice with the ROI calculator and EMI calculator.
Shops, clinics and small businesses
Daytime-heavy shops and clinics are an ideal fit. See the small shop post and our Neyyattinkara shop case study.
Churches, schools and hospitals
Large roofs and daytime loads make 20–100 kW projects common, and one project can equal 20–50 homes. See the institutional guide and hospital post, or our institutional solar service.
Industry and hospitality
Cashew, ceramics, cold storage and processing units run through working hours. Hotels and homestays run AC and hot water long hours. Read our Kollam industry post, the homestay post and the industrial case study.
Farms and pumps
Solar pumps replace diesel and cut grid bills; see the farm post, the PM-KUSUM guide and the solar pump service.
How to size a commercial or institutional system
- Gather 12 months of bills to see seasonal and monthly use.
- Find the daytime share: how much runs between 8 am and 5 pm. Solar should cover that, not the night.
- Check the connection: tariff category, sanctioned load or contract demand, phase.
- Measure usable roof: about 10 sq m of shadow-free area per kW.
- Choose size: typically 60–90% of daytime consumption, and no more than your sanctioned load allows.
Worked example: a 50 kW system for a school or hospital
| Buy (CAPEX) | Pay per unit (RESCO) | |
|---|---|---|
| Upfront cost | ≈ ₹25 lakh (₹50,000/kW) | ₹0 |
| Yearly generation | ≈ 72,500 units | ≈ 72,500 units |
| Grid tariff / RESCO rate | ₹8 / unit | ₹5.5 / unit |
| Yearly saving | ≈ ₹5.8 lakh | ≈ ₹1.8 lakh |
| Payback | ≈ 4.3 years | Immediate |
| After 25 years | Own the plant | Plant may transfer or be bought out, per contract |
Illustrative, excluding depreciation and loan interest. Model yours in the ROI calculator.
Roof types and the structural audit
- RCC roofs: simplest; check waterproofing and load.
- Metal sheet roofs: need purlin strength checks and proper clamps; wind uplift matters in Kanyakumari.
- Asbestos sheet roofs: require specialist handling and an approved mounting method; do not drill casually.
- Old church and school buildings: check rafters, and consider a ground or car-park structure if the roof cannot take the load.
Procurement checklist for trusts and managements
- Appoint one decision-maker and a small committee.
- Commission an independent energy audit.
- Invite 3 quotes against the same specification.
- Compare bill of material, warranties, performance guarantee and O&M terms.
- Check installer references and visit a completed site.
- Agree a payment schedule linked to milestones.
Our institutional solar service can run the audit and the comparison.
Approvals and connection
Commercial and industrial systems connect under KSEB or TNPDCL rules that depend on connection type and size. Net metering, net billing, or captive arrangements can apply; large systems may need extra approvals. Ask the utility for the route that applies to your sanctioned load and confirm any grid-support charges for larger systems in Kerala. Start the application early; it is often the longest step.
Risks and how to manage them
| Risk | How to manage it |
|---|---|
| Roof leaks or damage | Waterproofing scope and liability in writing |
| Underperformance | Performance guarantee and monitoring access |
| Installer disappears | Warranty from manufacturers, retention of final payment |
| Tariff or rule changes | Conservative payback, flexible sizing, review annually |
| Building ownership | Lease length and consent if you rent |
Real examples
See how a Neyyattinkara shop and an industrial unit approached it, and how a large villa cut a ₹25,000 bill to about ₹250.
District guides
See local segments, funding and checks for Trivandrum, Kollam and Kanyakumari.
Sources and how we maintain this page
Reviewed on 2026-10-03 and re-checked monthly or when a rule changes. Where a figure comes from news or trade reports, the page says so.
