Unpopular opinion: Rooftop solar is a better post-tax investment than most mutual funds
UPDATE ALL CALCULATION IS WRONG
THANK YOU FOR REVIEWING MY WRONGDOING
The more I look into rooftop solar numbers properly, the more I realize people completely underestimate how good of an asset it actually is.
Everyone is chasing the next small-cap mutual fund or momentum stock hoping for a clean 12–14% CAGR, but barely anyone treats a rooftop solar installation as a core part of their financial portfolio.
Unlike the stock market, solar returns are literally actual cash staying in your pocket every single month from day one.
There are no market crashes, no red portfolio screenshots, no fund manager drama, and no checking your portfolio every morning like your life depends on it.
But here’s the catch — almost all solar calculations you see online from installers are absolute garbage.
They are aggressively optimistic because they assume:
Every single unit you generate directly offsets your bill at retail price.
Exported power gets paid at the same rate you buy it.
Zero maintenance cost and zero panel degradation.
Your solar inverter lives forever.
Real life doesn't work that way.
I decided to run a brutal, zero-BS financial model for a premium ~₹10L residential Waaree setup in Gujarat (DGVCL area) to find the real XIRR.
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The Setup & The Real Constraints
* System Size: ~20kW (Fits a large independent house/bungalow).
* Net Capital Outflow: ~₹9.22L (Gross ₹10L minus the max ₹78k PM Surya Ghar subsidy cap).
* Generation: A solid 20kW system realistically generates around 28,000 units/year in Gujarat.
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The Consumption Trap (The Edge Case)
Even a massive bungalow running multiple ACs is realistically only going to consume about 14,000 units a year.
This means half of your generated electricity gets exported back to the grid.
Here is where the math gets ugly for most people:
DGVCL charges you /₹8/unit (highest slab + fuel surcharge) when you consume, but they only buy back your surplus exported units at the APPC rate of **/₹2.25/unit**.
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The Year 1 Economics
* Savings from self-consumption (14k units × ₹8): ₹1.12L
* Export earnings (14k units × ₹2.25): ₹31.5k
* Minus Operations & Maintenance (Cleaning/Electricals): -₹12k
Actual Year 1 Net Profit: ~₹1.31L
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The 25-Year Long-Term Model
I factored in:
* 3% annual grid tariff inflation
* 0.4% annual panel degradation
* 5% yearly O&M inflation
* A massive ₹1,00,000 hit around Year 11–12 for a full inverter replacement (because inverters do not last 25 years, period)
After running the internal rate of return on these exact, unforgiving cash flows:
* True Payback Period: ~6.8 Years (You break even in Year 7)
* Total Net Profit over 25 years: ~₹29.8L
* Real-Life XIRR: 13.2%
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My Takeaway
A 13.2% post-tax, virtually risk-free XIRR from a physical asset sitting on your roof is absolutely insane.
It’s pegged to inflation (as grid prices rise, your savings increase), it’s completely un-correlated to Nifty fluctuations, and it has zero capital gains tax because it’s technically "saved expense."
Solar only becomes a bad investment if you completely oversize your system relative to your own base consumption — forcing you to dump most of your power into the grid for a measly ₹2.25.
But if your household or business already has a naturally high electricity bill, rooftop solar genuinely feels like one of the most underrated, asymmetric risk-reward investments in India right now.
Change my mind.
What am I missing here?
UPDATE ALL CALCULATION WRONG SORRY