PM Surya Ghar Existing Solar Upgrade 2026: Additional Subsidy, Expansion and Reuse Guide

Official Rule for a Pre-Existing Rooftop Solar Plant

The residential CFA operational guideline states that a rooftop solar installation of a residential consumer or RWA that has availed CFA under a prior or current MNRE rooftop-solar scheme and subsequently increases the installation size is eligible for additional CFA only for the balance capacity up to three kW of the overall rooftop plant size.

Which Type of Upgrade Are You Planning?

For society projects, use the PM Surya Ghar RWA subsidy guide .

Additional CFA Examples for Existing Solar

How Previous Subsidy Affects the New CFA Claim

Preserve the earlier plant and subsidy history even when the old CFA rate was lower. In the guideline example, a one-kW Phase II system that received ₹14,588 and later expands to four kW receives ₹48,000 on the supported two-kW balance. The example does not provide another three-kW full subsidy merely because the earlier amount was lower.

• Old scheme or programme name
• Old application and sanction number
• Old installed DC capacity
• Old subsidy amount and payment date
• Old module and inverter records
• Existing meter and commissioning date
• New added module capacity
• New total cumulative plant capacity
• Balance supported capacity up to three kWp overall

What If the Existing Solar Plant Never Received CFA?

The explicit pre-existing-RTS clause describes a plant that already availed CFA under a prior or current MNRE scheme. It does not state a universal automatic CFA method for every privately installed or unregistered old system that never received subsidy. An already completed plant may also predate the required National Portal application, registered-vendor and inspection workflow.

1. Record when and how the old plant was installed.
2. Check whether it was approved by the DISCOM and linked to the same consumer connection.
3. Check whether any Central or State subsidy was received.
4. Check module DCR, model and serial records.
5. Ask the National Portal or DISCOM how the base capacity will be recorded.
6. Obtain written confirmation of eligible added capacity before ordering modules.
7. Do not use the calculator as proof of entitlement when no prior CFA record exists.

Relocation Does Not Create Fresh CFA

The operational guideline states that a rooftop solar installation is eligible for CFA only once after installation. When an already installed system is shifted or relocated to a new location, the relocated system is not eligible for CFA under the scheme.

Complete an Existing-System Audit Before Buying Anything

• Confirm old physical module quantity and wattage.
• Confirm old total DC capacity.
• Confirm inverter model, AC rating, phase and unused input capacity.
• Export at least 12 months of generation data.
• Check old module output and visible defects.
• Test insulation, polarity, earthing and protection through qualified personnel.
• Check roof leakage and structural corrosion.
• Check current sanctioned load, meter and billing mechanism.
• Check remaining OEM and CMC warranties.
• Identify all documents missing from the old project.

Assess maintenance history with the rooftop solar maintenance and warranty guide .

Should You Increase Solar Capacity?

More capacity is not automatically better. Compare the old system’s actual generation with present consumption, daytime load, export credit, roof area, tariff and future appliances such as an EV, heat pump or air conditioner.

Estimate the right total capacity through the home solar system-size guide and value through the PM Surya Ghar savings calculator .

Can the Old Mounting Structure Be Reused?

Reuse is possible only after a structural and condition audit. Newer modules may differ in length, width, frame thickness, clamp zone, weight and wind loading.

• Member dimensions and material grade
• Foundation, anchor, ballast and roof interface
• Corrosion and coating loss
• Loose fasteners and weld quality
• Original wind design and new module dimensions
• Clamp position and manufacturer requirements
• Drainage, waterproofing and maintenance access
• Added row wind interaction and shading
• Remaining design life
• Responsibility and warranty after modification

Review usable space using the solar-panel rooftop-area guide .

Can Old and New Solar Modules Work Together?

• Open-circuit voltage and temperature correction
• Maximum-power voltage
• Short-circuit and operating current
• Module degradation and condition
• Bypass-diode and connector compatibility
• String module count
• MPPT operating window
• Maximum inverter input current
• Roof orientation and shade pattern

DCR and ALMM Checks for the Expanded Plant

The guideline says modules used in the installation must be domestically manufactured from domestically manufactured cells and that use of non-DCR modules in any form makes the installation ineligible for CFA. For an expansion, verify the old and new module records and obtain written portal or DISCOM guidance if an old section creates uncertainty.

• Old module manufacturer, model and serial register
• Old DCR or prior-scheme compliance record
• New module domestic-cell and domestic-module evidence
• Current applicable ALMM module and cell records
• New invoice and delivery batch
• No undocumented module substitution
• Physical label, portal, PCR and invoice consistency

Use the PM Surya Ghar DCR module verification guide .

Can the Existing Solar Inverter Be Reused?

An inverter can be reused when the expanded module design remains within every manufacturer limit and the unit meets current scheme and DISCOM requirements.

Follow the solar-inverter selection guide .

When Should the Inverter Be Replaced?

• The old inverter cannot accept the new DC voltage or current.
• There are not enough independent MPPT inputs.
• The old unit has repeated faults or poor service support.
• The connection changes from single phase to three phase.
• The planned battery requires a compatible hybrid architecture.
• The old inverter lacks required protection or certification.
• Monitoring and data cannot distinguish old and new arrays.
• Expected clipping or derating makes reuse uneconomic.

Redesign Strings and MPPTs for the Expansion

• Keep different orientations on separate MPPTs where practical.
• Avoid mixing materially different operating currents in one series string.
• Check parallel-string current and input connector limits.
• Use matched approved connectors; avoid improvised connector pairs.
• Update string labels, layout and single-line diagram.
• Retest polarity, insulation and open-circuit voltage.
• Record MPPT values at commissioning.

Adding Battery Storage or Converting to Hybrid

The guideline allows additional technology components such as battery storage, but CFA calculation remains based on eligible solar-module capacity. Grid-connected behind-the-meter or hybrid systems are subject to approval by the respective Electricity Regulatory Commission and DISCOM inspection of reverse-power protection. Fully off-grid installations are not eligible for CFA.

• Confirm the State regulator permits the proposed configuration.
• Confirm whether the existing inverter can support battery operation.
• Separate backed-up circuits from non-backed-up high loads.
• Check battery chemistry, usable capacity, cycle life and warranty.
• Check fire safety, ventilation and enclosure location.
• Check reverse-power relay or zero-export settings where required.
• Update SLD, protection and portal records.
• Do not describe standard on-grid solar as outage backup.

Compare configurations using the on-grid, hybrid and off-grid guide .

Sanctioned Load, Connection Phase and Feasibility

An expansion changes cumulative generation capacity and may require a new or updated utility record even when the old plant was approved. Current scheme measures simplify rooftop approval and provide automatic load enhancement up to 10 kW, but the live DISCOM workflow, phase and metering still must be correct.

• Old approved solar capacity
• New proposed total capacity
• Current sanctioned load or contract demand
• Single- or three-phase connection
• Existing and proposed inverter phase
• Service cable and distribution board capacity
• Transformer or local interconnection condition
• Updated feasibility or auto-load record

Use the PM Surya Ghar feasibility and load guide .

Does the Existing Net Meter Need Replacement?

The current meter may remain suitable, require reprogramming or need replacement, depending on phase, current rating, approved metering arrangement, cumulative capacity and State/DISCOM specifications.

Follow the PM Surya Ghar net-meter process guide .

Documents Required for an Existing-Solar Upgrade

Organise the file with the PM Surya Ghar documents checklist .

Existing Solar Upgrade Application Process

1. Collect the old application, subsidy, commissioning and equipment records.
2. Confirm the old subsidised DC capacity and current consumer connection.
3. Audit generation, roof, structure, inverter, strings, meter and protection.
4. Calculate the required new total capacity and possible CFA balance.
5. Check the current National Portal workflow for pre-existing RTS or capacity enhancement.
6. Confirm feasibility, load, phase and meter treatment with the DISCOM.
7. Select a registered vendor and freeze a compliant technical design.
8. Verify DCR and current applicable module/cell records before purchase.
9. Install and test the added system without compromising the old plant.
10. Update actual cumulative capacity, modules, inverter and photographs in the portal.
11. Complete DISCOM inspection, metering and commissioning updates.
12. Verify the e-token or eligible CFA amount reflects only supported balance capacity.
13. Preserve old and new warranties, serial maps, monitoring and CMC records.

Review registration in the PM Surya Ghar online application guide and track progress with the application-status guide .

Select a Registered Vendor Experienced in Expansion Work

• Current National Portal registration
• Experience with brownfield or existing-plant expansion
• Written audit of old equipment
• Clear separation of old and new work
• Exact DCR modules and inverter design
• String and MPPT calculations
• Structure and roof responsibility
• Portal and DISCOM capacity-update support
• Warranty treatment of inherited equipment
• Five-year CMC for the new work and complete-system responsibility
• Itemised price and milestone payments

Compare companies through the PM Surya Ghar registered-vendor guide .

Installation-Day Rules for a Solar Expansion

• Record the old system’s final pre-work generation and alarms.
• Photograph old module and inverter serials.
• Use a documented shutdown and isolation process.
• Protect old modules, cables and roof waterproofing.
• Keep old and new component batches identifiable.
• Use approved matched connectors and cable.
• Update structure and wind calculations.
• Label new strings, isolators and protection.
• Retest the whole cumulative system.
• Update monitoring capacity and ownership.
• Capture geo-tagged completion photographs.

Follow the PM Surya Ghar solar-installation process guide .

What the DISCOM May Verify After Expansion

• Consumer account and old approved plant
• Old and new cumulative module DC capacity
• Prior subsidy and eligible balance capacity
• DCR compliance and all module serials
• Inverter model, rating, phase and MPPT design
• Structure, cabling, isolation and labels
• Earthing, surge and anti-islanding protection
• Updated meter and agreement
• Invoice, PCR, SLD, tests and photographs
• Portal and physical-plant consistency

Prepare with the PM Surya Ghar DISCOM inspection guide .

Warranty and CMC After Capacity Expansion

Old and new components can have different warranty dates. The new vendor must define whether it accepts responsibility only for the added work or for the integrated system. Under the scheme, registered vendors provide five years of free repair and maintenance from commissioning for their covered installation, but the expansion’s commissioning and responsibility should be written clearly.

Calculate Upgrade Cost and Savings Correctly

An expansion can cost more per added kWp than a new clean installation because it may require audit, rewiring, structure modification, phase conversion, meter work or inverter replacement. Compare the net cost after only the eligible balance CFA.

• Separate essential repair from optional expansion cost.
• Do not apply CFA to capacity above the supported balance.
• Include the cost of new inverter only when technically necessary.
• Include roof restoration and meter work.
• Use the current household tariff and export credit.
• Include downtime during modification.
• Include post-CMC maintenance and future inverter reserve.

Compare household scale through the 1kW , 2kW and 3kW cost guides .

Where finance is needed, review the PM Surya Ghar solar-loan guide and track CFA using the subsidy-payment status guide .

Correction, Approval Delay or Rejection During an Upgrade

Use the application-correction guide , approval-delay guide and rejected-application guide .

If a new installer must take over, follow the PM Surya Ghar change-vendor guide .

Existing-Solar Upgrade Scams and Red Flags

• Use the consumer’s own official login.
• Verify the old subsidy history before signing.
• Demand the cumulative capacity calculation.
• Verify DCR, module and inverter models physically.
• Keep OTP, password and bank credentials private.
• Report suspected false invoices, forged labels or bribery to appropriate authorities.

Frequently Asked Questions

Upgrade One Cumulative System, Not Two Unrelated Plants

A safe expansion connects the old scheme history and new work into one consistent record: consumer account, old CFA, old capacity, new added capacity, cumulative modules, inverter, strings, structure, meter, invoice, inspection, token, warranty and maintenance. Calculate the supported balance before ordering equipment.

Begin with the complete PM Surya Ghar guide and verify the upgrade’s general eligibility using the eligibility guide .