Solar vs Gold vs Fixed Deposits vs Mutual Funds: Comparing Return on Investment

A ₹3 lakh rooftop solar system can generate ~₹5.39 lakh in gross electricity savings over 10 years. Even after allowing for maintenance and an inverter replacement, the system recovers its initial cost and delivers ~₹1.76 lakh in additional economic benefit over the period. It also continues generating electricity beyond Year 10.

But how does that compare with putting the same ₹3 lakh into a fixed deposit, gold, or a mutual fund? The answer is not as simple as comparing four return percentages.

Rooftop solar reduces a recurring household expense and leaves you with an operating energy-producing asset, whereas FDs, gold, and mutual funds create financial assets that can generally be sold or redeemed.

To make the comparison meaningful, we will use the same ₹3 lakh starting amount and 10-year period for all four options and account for relevant costs and taxes. This blog shows how their returns differ, along with the trade-offs in risk, liquidity, inflation protection, and the purpose each investment serves.

Solar vs Gold vs FD vs Mutual Funds Returns at a Glance 

Rooftop solar creates value through bill savings, while fixed deposits, gold, and mutual funds produce direct financial returns. This difference affects how they should be compared.

Here’s a snapshot of the key differences we’ve explained across this blog:

Are Rooftop Solar and Financial Investments Directly Comparable? 

No. Rooftop solar and financial investments are not directly comparable because they create value in different ways. Solar reduces a recurring household expense through electricity savings, while fixed deposits, gold, and mutual funds create financial assets that can generally be redeemed or sold.

They can still be compared on a common basis by looking at how much financial value the same investment creates over the same period, while accounting for the different forms of returns, costs, taxes, liquidity, and residual value.

• Rooftop solar creates value through electricity savings: It reduces the amount of grid electricity a household needs to purchase and may also earn credits for surplus electricity exported to the grid. Even after the comparison period ends, a rooftop solar system continues generating electricity and producing savings.
• Fixed deposits, gold, and mutual funds create direct financial value: FDs earn interest, gold may appreciate in price, and mutual funds may grow with the performance of their underlying investments.
• Each option requires a suitable return metric: Solar can be assessed using ROI (return on investment), payback period, and IRR (Internal Rate of Return), which is the annualized rate of return that accounts for the timing of cash flows over the investment period. An FD, by contrast, is compared using its interest rate and post-tax maturity value. Gold and mutual funds are commonly compared using CAGR (Compound Annual Growth Rate) and their net value after costs and taxes.

Therefore, the comparison between solar vs gold vs FD vs mutual funds should examine the total value created after costs and taxes rather than placing solar’s annual bill savings directly against the advertised return percentage of a financial product.

How Should Returns Be Compared Fairly? 

A fair comparison of solar vs gold vs FD vs mutual funds must use the same initial amount and period. It must consider expenses and taxes instead of comparing gross solar savings with advertised financial returns.

For the comparison of the four in this blog, we will use the following assumptions:

• Investment of ₹3 lakh in each option.
• Using a 10-year evaluation period.
• Comparing benefits after the stated costs and taxes.
• Keeping the original investment and the return separate.

An FD, gold investment, or mutual fund retains redeemable value. Solar converts money into a system that reduces electricity expenses.

How Do Solar, FDs, Gold, and Mutual Funds Generate Returns? 

These four options generate value differently.

• Solar reduces electricity expenses by up to 90% or more
• Fixed deposits pay interest
• Gold benefits from price appreciation
• Mutual funds gain or lose value according to the performance of their underlying investments.

Let’s understand each of the four in detail.

Returns From Rooftop Solar 

Rooftop solar generates returns through electricity bill savings. The photovoltaic (PV) system reduces grid purchases, while surplus generation may earn credits under applicable DISCOM regulations.

Here’s a simple formula that can be used to calculate returns from rooftop solar:

The payback period shows how long savings take to recover the installation cost. Long-term solar panel investment return (ROI) also considers maintenance, panel degradation, and component replacement.

Returns from Fixed Deposits 

A fixed deposit generates returns through bank interest. The maturity amount depends on the initial deposit, interest rate, tenure, and compounding frequency.

Here’s a simple formula that can be used to calculate returns from FDs:

The advertised rate is not the final return. Interest is generally taxable at the applicable slab, while inflation can reduce the maturity amount’s purchasing power.

Returns From Gold 

Gold produces a return when its selling price exceeds its total purchase cost. It does not ordinarily generate regular interest or monthly income.

Here’s a simple formula that can be used to calculate returns from gold:

Physical gold may involve purchase, storage, and selling costs, while market-linked gold products may have other charges.

Returns from Mutual Funds

Mutual funds produce returns when the value of their underlying investments rises. Their performance is market-linked, which means the value can also fall.

Here’s a simple formula that can be used to calculate returns from mutual funds:

The outcome depends on the fund category, period, market performance, expenses, and tax. Historical returns do not guarantee future performance.

Worked Example: Investing ₹3 Lakh for 10 Years in Solar, Gold, FDs, and Mutual Funds 

This example compares ₹3 lakh over 10 years. The figures are illustrative, not guaranteed returns.

Rooftop Solar Outcome

For solar, the ₹3 lakh investment becomes a rooftop asset that generates electricity savings.

The calculation below considers increasing electricity tariffs, declining panel output, annual maintenance, and an inverter replacement in Year 8.

The calculation is:

Net economic benefit = ₹5.39 lakh gross savings − ₹3 lakh initial investment − ₹63,000 maintenance and inverter costs = ~₹1.76 lakh

Please note: No resale value has been assigned to the solar system after Year 10. However, the system will continue generating electricity and producing savings after the comparison period.

Fixed Deposit Outcome

For the FD comparison, the same ₹3 lakh is invested for 10 years at an assumed annual interest rate of 7%, compounded annually. Tax is then applied to the interest income.

Here’s a snapshot of the approximate outcome based on these assumptions:

Important: The exact post-tax amount will depend on the investor’s tax slab and how tax is paid during the investment period.

Gold Outcome

For gold, the calculation assumes that the ₹3 lakh investment appreciates by an average of 8% per year for 10 years. Purchase, selling, and other costs are deducted before arriving at the final value.

Mutual Fund Outcome

For the mutual fund calculation, ₹3 lakh is invested in an equity-oriented mutual fund for 10 years. The assumed 10% Compound Annual Growth Rate (CAGR) already accounts for the expense ratio, so it is not deducted separately.

Final 10-Year Comparison Between Solar vs Gold vs Fixed Deposits vs Mutual Funds

Solar, gold, FDs, and mutual funds generate returns in different ways. Solar primarily delivers returns through electricity bill savings, while gold, FDs, and mutual funds retain a financial value that can be realised later. So, instead of comparing them on a single percentage, it makes more sense to compare their overall returns, payback period, and long-term value.

Here’s a side-by-side comparison across relevant factors:

Rooftop Solar System vs Fixed Deposit Returns

In a solar vs fixed deposit comparison, solar may generate greater long-term economic savings for a homeowner with high electricity consumption and a suitable roof. An FD may be preferable when predictable returns and access to the invested money matter more.

Solar may offer better value when:

• The homeowner has a suitable, largely shade-free roof.
• Electricity consumption and the applicable tariff are high.
• The grid-tied solar system offsets a substantial share of grid purchases.
• Emergency savings are already available elsewhere.

An FD may be more suitable when:

• The money may be required within a few years.
• The home is rented, or the roof is unsuitable.
• Electricity consumption is too low to produce high savings.

Rooftop Solar System vs Gold Investment 

Solar and gold serve different purposes.

• Solar uses an owned rooftop to reduce a recurring household expense.
• Gold is a transferable financial asset whose return depends on future market prices.

Solar provides monthly bill reductions and direct protection against tariff increases. Its output can be estimated, although actual generation may vary.

Gold is easier to sell, requires no suitable roof, and supports diversification. However, it produces no electricity savings or interest, and its value can fall.

Rooftop Solar System vs Mutual Funds 

A solar vs mutual fund comparison involves two very different assets.

• Solar creates household savings through free solar electricity generation.
• A mutual fund creates a liquid, market-linked financial corpus that you can partially or fully redeem.

Solar has limited direct exposure to stock market movements and reduces electricity expenses. Mutual funds offer diversification, liquidity, and potential long-term wealth creation without requiring property ownership.

How Does Inflation Affect the Four Options? 

Inflation affects each option differently. Solar can benefit when electricity tariffs rise, while tax and inflation can weaken the real return from an FD. Gold and equity-oriented mutual funds may outpace inflation, but their market-linked performance is uncertain.

• Solar: Rising electricity tariffs increase the value of every unit consumed at home. In most Indian states, tariffs rise by 3-6% annually.
• Fixed deposit: The principal and interest may grow, but tax and inflation can reduce the real purchasing power of the maturity amount.
• Gold: Gold can support diversification during inflation or economic uncertainty, but it does not increase consistently every year.
• Mutual funds: Equity-oriented funds may outperform inflation over long periods, but short-term losses remain possible.

Which Option Is Better for Your Financial Goal? 

The right option depends on what the money must achieve. Solar suits a homeowner seeking long-term electricity savings, while FDs, gold, and mutual funds address liquidity, predictability, diversification, and wealth-building needs.

Here’s how you can decide which is the better option in which situation:

Needless to say, the solar ROI in India can be very attractive for a homeowner with sufficient consumption, a suitable roof, and a long ownership period. Book a free consultation with SolarSquare to assess your roof, consumption, applicable subsidy, expected generation, savings, and payback.

Frequently Asked Questions

Can solar, FDs, gold, and mutual funds be used together? 

Yes. Solar can reduce electricity expenses, FDs can support short-term goals, gold can diversify a portfolio, and mutual funds can build long-term wealth. The mix should reflect the household’s goals, liquidity needs, income stability, and risk tolerance.

How to check whether solar will deliver good returns for your home?

Review one year of electricity bills, roof conditions, estimated generation, self-consumption, tariff slabs, export-credit rules, maintenance, and financing costs. A reliable estimate should use your actual consumption rather than a generic percentage for rooftop solar return on investment. You can also check the estimated savings and ROI using SolarSquare’s free solar savings calculator.

Is solar better than a fixed deposit in India? 

In most scenarios, yes. Solar offers greater economic value when it offsets a high electricity bill for many years. A fixed deposit, on the other hand, may be better when the investor needs liquidity and predictable maturity proceeds.

What is the average return on rooftop solar? 

The rooftop solar return on investment may be approximately 15% to 18% per year. Actual returns vary with installation cost, generation, electricity tariff, self-consumption, maintenance, degradation, financing, and applicable export-credit rules.

How long does rooftop solar take to recover its cost? 

Rooftop solar may recover its cost in two to five years. The actual payback period depends on the net installation cost, available subsidy, annual electricity generation, household consumption, electricity tariff, and maintenance expenses.

Is solar safer than a mutual fund investment? 

Yes, this is true in the sense that returns from solar are not related to market risks. Solar avoids direct stock market volatility. Mutual funds, on the other hand, are liquid and diversified, but their value can fall with the market.

Which is easier to convert into cash: gold or rooftop solar? 

Gold can usually be sold, subject to its form and applicable costs. Rooftop solar is attached to a property and cannot generally be liquidated separately. Its financial value is realized gradually through electricity savings.

Does the PM Surya Ghar Muft Bijli Yojana subsidy increase solar ROI?

Yes. The PM Surya Ghar Muft Bijli Yojana Subsidy reduces the homeowner’s net installation cost, which can shorten the payback period and improve ROI. Eligibility, system requirements, vendor selection, installation, verification, and disbursal remain subject to the applicable rules.

Should inverter replacement be included in solar ROI?

Yes. A long-term calculation should include foreseeable system expenses, including maintenance and possible inverter replacement. Excluding these costs can overstate lifetime savings.