Solar cost in Mumbai for a 3 kW rooftop system works out to ₹1,02,000-₹1,47,000 after the ₹78,000 PM Suryaghar subsidy in 2026. A 5 kW system lands at ₹2,22,000-₹2,97,000, and a 10 kW system at ₹5,22,000-₹6,72,000. Those are the numbers every Mumbai homeowner quotes back to us, but the real question is which size matches your electricity bill, because Mumbai is the only major Indian city where your DISCOM, Adani Electricity in the western suburbs, BEST in South Mumbai, or MSEDCL in the extended suburbs, changes your payback by 2 full years for the identical system. This guide gives you size-by-size price tables, the Adani Electricity and BEST tariff slabs your savings are calculated against, and the payback maths for each combination.
Direct answer. In 2026, a fully installed on-grid rooftop system in Mumbai costs ₹60,000-₹75,000 per kW before subsidy. After the PM Suryaghar subsidy of ₹78,000 (fixed for any system of 3 kW or more, per MNRE), a 3 kW system costs ₹1,02,000-₹1,47,000, a 5 kW system ₹2,22,000-₹2,97,000, and a 10 kW system ₹5,22,000-₹6,72,000. Payback runs 3-4 years in BEST territory and 4.5-6 years in Adani Electricity territory for high-consumption homes.
This post is the size-by-size companion to our solar installation cost Mumbai guide, which covers who can install in Mumbai and the three-DISCOM structure. Here we go deeper on the three sizes homeowners actually shortlist: 3 kW, 5 kW, and 10 kW.
Mumbai Solar Cost at a Glance: 3 kW, 5 kW, 10 kW
Every price in this article assumes a complete on-grid system: ALMM-listed panels, a BIS-certified string inverter, hot-dip galvanised mounting (marine grade for coastal Mumbai), wiring, earthing, net metering application, and documentation. Gross cost in Mumbai runs ₹60,000-₹75,000 per kW, roughly 8-12% above Gujarat cities because of higher labour rates, high-rise access logistics, and marine-grade hardware.
The master table for the three sizes, with Mumbai-specific generation estimates:
| System Size | Gross Price | Subsidy | Net Price | Monthly Generation | Roof Area Needed |
|---|---|---|---|---|---|
| 3 kW | ₹1,80,000-₹2,25,000 | ₹78,000 | ₹1,02,000-₹1,47,000 | 390-450 kWh | 250-300 sq ft |
| 5 kW | ₹3,00,000-₹3,75,000 | ₹78,000 | ₹2,22,000-₹2,97,000 | 650-750 kWh | 400-500 sq ft |
| 10 kW | ₹6,00,000-₹7,50,000 | ₹78,000 | ₹5,22,000-₹6,72,000 | 1,300-1,500 kWh | 800-1,000 sq ft |
Source: Heaven Green Energy benchmark pricing 2026; subsidy structure per MNRE PM Suryaghar guidelines, 2026. Generation assumes 5.0-5.4 kWh/m²/day irradiation and Mumbai’s 4 month monsoon.
Notice the asymmetry: the subsidy does not scale. Going from 3 kW to 10 kW adds ₹4.2-₹5.25 lakh in gross cost but zero additional subsidy. The ₹78,000 covers 35-43% of a 3 kW system but only 10-13% of a 10 kW system. This is the single most important fact in Mumbai solar pricing, and the sections below show what it does to each size’s payback.
3 kW Solar System Price in Mumbai
A 3 kW system is Mumbai’s most installed residential size, and the subsidy maths explains why. At ₹1,80,000-₹2,25,000 gross and ₹1,02,000-₹1,47,000 net, the PM Suryaghar subsidy covers the highest share of the ticket at this size. It is also the largest size where the subsidy formula (₹30,000 per kW for the first 2 kW, ₹18,000 for the third) pays out in full.
Who a 3 kW system fits in Mumbai:
- 2 to 3 BHK homes consuming 350-500 units per month. Monthly generation of 390-450 kWh covers 80-95% of that load in the non-monsoon months.
- Row houses and bungalows in Borivali, Kandivali, Malad, Powai, and Chembur with 250-300 sq ft of shadow-free roof.
- Low-rise society flats with an allotted terrace portion, which is the realistic ceiling for most society NOC approvals anyway.
What the bills look like: an Adani Electricity household using 450 units a month pays roughly ₹3,400-₹3,800 across slabs. A 3 kW system generating 420 kWh cuts that to the fixed charges plus a small residual, saving ₹3,000-₹3,400 per month from October to May, and ₹1,500-₹2,000 in the monsoon months. Annual saving: ₹30,000-₹34,000. That puts 3 kW payback at 3.5-4.5 years in AEML territory and 2.5-3.5 years for a BEST consumer on the higher slabs.
💰 Real numbers
A Maharashtra homeowner on X reported a 5 kW on-grid install at ₹3.6 lakh gross with the ₹78,000 subsidy credited within a month, and noted the Maharashtra process ran smoothly end to end. Another reported a 3.78 kW system at ₹2.05 lakh gross generating 650 kWh per month with a 3 year payback. These match our own Mumbai install economics closely.
If your monthly bill is under ₹2,000, a 3 kW system is oversized for your load. The 3kW vs 5kW vs 10kW comparison walks through the national sizing logic; the Mumbai-specific twist is that lower consumption pushes you into Adani’s and MSEDCL’s cheapest slabs, where each solar unit saves only ₹3.45-₹5.55, and payback stretches past 6 years.
5 kW Solar System Price in Mumbai
The 5 kW bracket is where Mumbai’s economics get interesting, and where most bad sizing decisions happen. Gross cost is ₹3,00,000-₹3,75,000; after the same flat ₹78,000 subsidy, you pay ₹2,22,000-₹2,97,000. Effective post-subsidy cost per kW rises from ₹34,000-₹49,000 (3 kW) to ₹44,400-₹59,400 (5 kW), so you are paying more per unit of capacity and the subsidy does not help you.
A 5 kW system makes sense for:
- 3 to 4 BHK homes with 2 or more ACs, monthly consumption of 600-800 units, and bills of ₹5,000-₹8,000.
- BEST territory homes in South Mumbai. This is the one Mumbai segment where 5 kW economics beat 3 kW economics, because every unit you self-consume replaces power billed at ₹10.85-₹13.05. Annual savings at 700 kWh/month generation: ₹75,000-₹85,000, giving payback of 3-3.5 years even at the higher per-kW cost.
- Bungalows planning an EV within 2 years. An EV adds 250-350 units per month; sizing at 5 kW today avoids a costly capacity addition later, since a second subsidy claim on the same connection is not allowed.
Where 5 kW goes wrong: homes consuming under 500 units per month. Generation of 650-750 kWh against a 450-unit load means 200-300 units exported monthly, and exports are settled at the MERC Average Power Purchase Cost of roughly ₹4.10-₹4.40 per kWh, not your retail rate. You effectively donate the difference. On Adani Electricity, where the top slab is ₹8.55, oversized 5 kW systems push payback from 4.5 years to 7+ years.
Curious what solar would cost for your home? Use our free solar calculator, enter your Adani or BEST bill amount and get your subsidy, savings, and payback in 60 seconds.
For the application route by DISCOM, see our PM Suryaghar Adani Electricity guide and the PM Suryaghar BEST Mumbai process.
10 kW Solar System Price in Mumbai
A 10 kW system in Mumbai costs ₹6,00,000-₹7,50,000 gross and ₹5,22,000-₹6,72,000 after subsidy. This is a different product category from 3 kW and 5 kW: it is a villa, bungalow, or society-common-area system, not a flat system. You need 800-1,000 sq ft of shadow-free roof, which almost no individual Mumbai apartment can offer.
Three realities define 10 kW economics in Mumbai:
- The subsidy is nearly irrelevant. ₹78,000 against a ₹6-7.5 lakh ticket is 10-13%. Buy a 10 kW system because the savings maths works, not because of the scheme.
- It is the MERC net metering ceiling. Residential net metering in Maharashtra caps at 10 kW under the MERC (Distributed Renewable Energy) Regulations, 2024. Larger residential loads must move to a different metering arrangement.
- Payback is the longest of the three sizes, unless the load justifies it. Generation of 1,300-1,500 kWh per month against consumption below 1,000 units means heavy export at ₹4.10-₹4.40 APPC. For a genuinely large consumer (1,200+ units monthly, bills of ₹12,000-₹18,000), annual savings of ₹1,10,000-₹1,30,000 give payback of 4.5-5.5 years. For everyone else, 6-8 years.
The exception that works well: housing society common-area systems. A 10 kW array on the society meter offsets lift, pump, and corridor lighting loads at commercial tariffs, and group housing gets a separate ₹18,000 per kW subsidy slab. Our solar for housing societies guide covers that structure in detail.
Adani Electricity and BEST Tariffs: What Your Solar Units Are Actually Worth
Your savings per solar unit equal the retail tariff you avoid, so the DISCOM slab table matters more than the system price table. Here are the two residential tariff schedules that decide Mumbai paybacks.
Adani Electricity Mumbai (AEML) domestic slabs (energy charges, per the MERC-approved schedule on adanielectricity.com, 2026):
| Monthly Consumption | Energy Charge (approx.) |
|---|---|
| 0-100 units | ₹3.45/kWh |
| 101-300 units | ₹5.55/kWh |
| 301-500 units | ₹7.45/kWh |
| 501 units and above | ₹8.55/kWh |
AEML has also introduced time-of-day smart meter rebates: consumption during solar hours (9 AM to 5 PM) earns a rebate of 55 paise per unit, rising to 70 paise over the tariff period, per MERC’s MYT order. That slightly reduces daytime grid purchases, but your own solar generation at ₹7.45-₹8.55 avoided cost still beats the rebate by a wide margin.
BEST domestic slabs (South Mumbai island city, per the MERC tariff order, 2024 amendment; BEST consumers received a tariff reduction effective April 2026, as reported by Hindustan Times):
| Monthly Consumption | Energy Charge (approx.) |
|---|---|
| 0-100 units | ₹4.85/kWh |
| 101-300 units | ₹7.45/kWh |
| 301-500 units | ₹10.85/kWh |
| 501-700 units | ₹12.40/kWh |
| Above 700 units | ₹13.05+/kWh |
Wheeling charges, fuel adjustment, and electricity duty sit on top of both schedules. Even after the April 2026 reduction, BEST’s upper slabs remain India’s most expensive residential electricity, which is why South Mumbai paybacks are the fastest in the city despite identical system prices.
📘 Regulation note
Both AEML and BEST follow MERC's net metering framework: systems up to 10 kW qualify, rooftop capacity cannot exceed your sanctioned load, and annual surplus settles at APPC. The shared state process is documented in this Maharashtra DISCOM net metering guide. MSEDCL suburban consumers follow the same MERC rules with a different slab table; see our PM Suryaghar MSEDCL guide.
Savings and Payback per Size, per DISCOM
Putting the price tables and the tariff tables together, this is what each size delivers for a well-matched Mumbai household (consumption roughly equal to generation, so exports stay minimal):
| Size | Net Cost | Annual Savings, AEML (₹7-8.5/unit) | Annual Savings, BEST (₹10.8-13/unit) | Payback, AEML | Payback, BEST |
|---|---|---|---|---|---|
| 3 kW | ₹1,02,000-₹1,47,000 | ₹33,000-₹38,000 | ₹48,000-₹55,000 | 3.5-4.5 yrs | 2.5-3.5 yrs |
| 5 kW | ₹2,22,000-₹2,97,000 | ₹55,000-₹65,000 | ₹75,000-₹85,000 | 4.5-6 yrs | 3-3.5 yrs |
| 10 kW | ₹5,22,000-₹6,72,000 | ₹1,00,000-₹1,20,000 | ₹1,35,000-₹1,55,000 | 5.5-7 yrs | 4-5 yrs |
Savings figures are Heaven Green Energy calculations from 2026 install data, using Mumbai generation of 130-150 kWh per kW per month (annual average, monsoon-adjusted) and slab-matched avoided tariffs. They assume 85%+ self-consumption.
Three caveats before you trust any payback quote, ours included:
- Monsoon honesty. June to September cuts generation 35-40%. Any payback calculated on December output is fiction. Our figures above use annual averages.
- The subsidy is DBT, not a discount. You pay the gross price first; ₹78,000 arrives in your bank within about 30 days of net meter commissioning, per pmsuryaghar.gov.in. Budget the full gross amount. Maharashtra homeowners on X report subsidy credits ranging from 3 weeks to over a month, with MSEDCL areas seeing the longest waits.
- Tariff cuts work against savings. MERC approved a multi-year tariff reduction for Maharashtra distribution licensees (about 10% in FY 2026, per Moneycontrol reporting of the 2025 MYT order). Lower tariffs mean slightly lower savings per unit in future years; we have used current rates, so treat year 3+ savings as mildly optimistic.
The Mumbai Size-to-Slab Matching Rule
This is the framework we apply on every Mumbai site survey, and it is the reason our payback numbers hold up: the Mumbai Size-to-Slab Matching Rule. The rule: size your system so monthly generation covers only the units you actually buy above ₹7 per kWh, and no more.
How to apply it:
- Pull your last 12 bills and note the units in each slab, not just the total. Every DISCOM bill shows the slab split.
- Add up the units billed above ₹7/kWh. On Adani, that is everything above 300 units. On BEST, everything above 300 units (the ₹10.85 slab starts there). On MSEDCL, everything above 300 units (₹7.26 slab).
- Divide that monthly figure by 140 (Mumbai’s average monthly generation per kW). The result is your target kW.
- Cap the result at your sanctioned load and your available shadow-free roof area, whichever is lower.
Worked example, Andheri bungalow on Adani Electricity, 700 units per month: units above ₹7 = 700 minus 300 = 400. 400 ÷ 140 = 2.9 kW, so a 3 kW system. A 5 kW system here would export 250+ units monthly at ₹4.10-₹4.40, and payback would stretch from 4 years to over 6. This is the single most common sizing mistake we correct in Mumbai quotes.
The nuance worth admitting: the rule assumes your consumption stays flat. If you are adding an EV, a second AC, or converting a gas geyser to electric within 2 years, add that projected load in step 2 before dividing.
Hidden Costs and Quote Red Flags in Mumbai
Across the Mumbai quotes we audit for homeowners, these five items account for almost every case of a final bill exceeding the quote by 15-30%:
-
1
Marine-grade mounting quoted as an "extra" after signing. Coastal salt air corrodes standard structures within 3 to 5 years. Marine-grade hot-dip galvanised or stainless hardware adds Rs 8,000 to Rs 12,000 and belongs in the base quote, not a variation.
-
2
No shading analysis on a high-rise-shadowed roof. Adjacent towers can cut Mumbai rooftop yield 20 to 50 percent. A quote without a shadow study is a guess. Ask for the PVsyst or equivalent report.
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3
Non-ALMM panels priced in. Panels not on the ALMM list fail DISCOM inspection and forfeit the entire Rs 78,000 subsidy. Verify the exact panel model against the current ALMM list before paying an advance.
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4
Society NOC and net-metering charges missing. Society documentation support, DISCOM application fees, and the bi-directional meter cost Rs 5,000 to Rs 15,000 combined depending on DISCOM. These are routinely left out of the headline price.
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5
Payback quoted on peak-month generation. December output is 40 percent above the annual average. Demand the annual, monsoon-adjusted figure in writing.
⚠️ Watch out
Maharashtra homeowners on X report subsidy and net-metering friction: exports not recording on bills, commissioning stuck at the portal inspection step, and DBT delayed past 45 days, mostly in MSEDCL areas. AEML and BEST specific complaint threads are scarce, but the protection is the same everywhere: get every component, charge, and timeline in the written quote, and keep your application reference number for escalations.
For the full taxonomy of application failures, read our PM Suryaghar rejection reasons guide. Inverter compliance is its own trap; the current BIS and IEC requirements are summarised in this solar inverter regulations guide for India.
How Heaven Green Energy Helps
Heaven Green Energy is an MNRE-empanelled installer operating across Mumbai’s three DISCOM territories, with 10,000+ installations nationally and a dedicated Mumbai team that handles the parts of a Mumbai project that actually cause delays: society NOC drafting and resolution support, shading analysis for high-rise-shadowed terraces, DISCOM portal applications for AEML, BEST, and MSEDCL, and net-metering follow-up through commissioning. Every Mumbai quote we issue is built on the Size-to-Slab Matching Rule above, so the payback figure you sign is the payback figure you get.
- Residential Solar: 3 kW to 10 kW rooftop systems with PM Suryaghar subsidy handled end-to-end across AEML, BEST, and MSEDCL territories.
- Solar Calculator: enter your Adani or BEST bill and see size-by-size savings in 60 seconds.
- Solar cost Mumbai parent guide: who can install in Mumbai, and the three-DISCOM structure explained.
- Contact our Mumbai team: free site assessment with shadow analysis, proposal within 48 hours.
Ready for exact numbers for your roof? Our engineer visits within 24 hours, applies the Size-to-Slab Matching Rule to your last 12 bills, and sends a written proposal with annual, monsoon-adjusted savings. Get your free quote →
Frequently Asked Questions
What is the cost of a 3 kW solar system in Mumbai after subsidy?
A 3 kW on-grid rooftop system in Mumbai costs ₹1,80,000-₹2,25,000 before subsidy and ₹1,02,000-₹1,47,000 after the ₹78,000 PM Suryaghar subsidy (MNRE, 2026). The price includes ALMM-listed panels, a BIS-certified inverter, marine-grade mounting, net metering application, and documentation. Monthly generation is 390-450 kWh, which suits homes consuming 350-500 units per month. Payback runs 3.5-4.5 years on Adani Electricity tariffs and 2.5-3.5 years on BEST tariffs for well-matched loads.
How much does a 5 kW solar system cost in Mumbai in 2026?
A 5 kW system costs ₹3,00,000-₹3,75,000 gross and ₹2,22,000-₹2,97,000 after the ₹78,000 subsidy. Because the subsidy is capped at 3 kW, the effective post-subsidy cost per kW rises to ₹44,400-₹59,400, higher than a 3 kW system. A 5 kW system pays back fastest for BEST consumers with bills above ₹6,000 per month (3-3.5 years) and slowest for low-consumption Adani Electricity homes that would export most of the extra generation at the ₹4.10-₹4.40 APPC rate.
Does the ₹78,000 subsidy apply to 5 kW and 10 kW systems too?
Yes, but as a flat cap, not a scaled amount. PM Suryaghar pays ₹30,000 for 1 kW, ₹60,000 for 2 kW, and ₹78,000 for any system of 3 kW or larger, per MNRE 2026 guidelines. A 10 kW system receives the same ₹78,000 as a 3 kW system, so the subsidy covers only 10-13% of a 10 kW project cost. Housing societies installing for common-area loads use a separate slab of ₹18,000 per kW. The subsidy arrives by Direct Benefit Transfer within about 30 days of net meter commissioning.
Is Adani Electricity or BEST better for rooftop solar payback?
BEST, by a clear margin, for high-consumption homes. BEST’s upper residential slabs of ₹10.85-₹13.05 per kWh are the highest in India, so every self-consumed solar unit saves more than on Adani Electricity’s ₹7.45-₹8.55 top slabs. A 5 kW system pays back in 3-3.5 years in BEST territory versus 4.5-6 years in Adani territory for equivalent loads. The tradeoff: BEST feasibility approval runs slower (15-22 working days versus AEML’s 10-18) because BEST processes applications manually.
How many units does a 3 kW solar system generate per month in Mumbai?
A 3 kW system generates 390-450 kWh per month on an annual average in Mumbai, based on 5.0-5.4 kWh/m²/day irradiation (MNRE Solar Atlas, 2026). December to May output runs 480-540 kWh; the monsoon months of June to September drop to 250-320 kWh. Always size and calculate savings on the annual average of roughly 140 kWh per kW per month, not on peak-month figures, and have shading from adjacent towers assessed before finalising capacity.
Can I install a 10 kW solar system on my Mumbai housing society terrace?
As an individual flat owner, almost never: 10 kW needs 800-1,000 sq ft of shadow-free roof, and society terraces are common property. As a society, yes. Under PM Suryaghar’s group net metering provision, the society applies as a single consumer, installs on the shared roof, and offsets common-area loads like lifts and pumps at commercial tariffs, with a subsidy of ₹18,000 per kW. Individual bungalow and villa owners with sufficient roof area can install 10 kW under standard net metering, which MERC caps at 10 kW for residential connections.
What extra costs should I budget beyond the quoted system price in Mumbai?
Budget for five items routinely excluded from headline quotes: marine-grade mounting hardware (₹8,000-₹12,000, essential for coastal salt air), society NOC documentation support, DISCOM application and bi-directional meter charges (₹5,000-₹15,000 combined), any structural waterproofing or roof strengthening for older buildings, and a load-enhancement request with your DISCOM if your sanctioned load is below the system size. A transparent quote lists all five upfront; if yours does not, ask for the all-in figure in writing before paying an advance.
