Is solar actually worth it for your property?
Solar is a capital investment that pays back through avoided electricity purchases. Whether it is a good one depends on numbers specific to your property, so here is how the arithmetic actually works.
The four numbers that decide it
Most solar marketing leads with a savings percentage. That figure is meaningless without the inputs behind it, and the inputs vary enormously between two houses on the same street. There are four that matter:
01
Net cost after subsidy
What you actually pay once PM Surya Ghar assistance is credited, which is available only when a DISCOM-registered vendor installs the system. Without it, payback is measured against the full system price.02
Annual generation
How many units your system produces per year, which depends on local irradiance, roof orientation, tilt and shading. Two identical systems on different roofs do not generate the same amount.03
Your marginal tariff
Solar displaces the most expensive units on your bill first. A household in a high consumption slab avoids a much higher rate per unit than one in a low slab.04
Self-consumption ratio
Units you consume as you generate them are worth your full retail tariff. Exported units are credited at the net-metering rate, which is generally lower.
Multiply generation by the blend of those two rates and you have annual savings. Divide net cost by annual savings and you have a payback period in years. Everything else (degradation, inverter replacement, tariff inflation) adjusts that figure rather than replacing the method.
Those tariff slabs are set by TGERC in Telangana and APERC in Andhra Pradesh, and are revised periodically — which state you and your DISCOM (TGSPDCL, TGNPDCL, APSPDCL, APEPDCL or APCPDCL) fall under determines which order actually governs your bill.
When solar is a poor investment
We would rather tell you this before a site visit than after an installation. Solar is usually a weak proposition when:
- Your bill is genuinely low. Little consumption means little to displace, at a low marginal rate.
- Your roof is significantly shaded during peak hours. Shading between roughly 10am and 3pm removes the majority of the generation.
- You do not expect to stay. Payback runs over years, and while a system adds value, it rarely returns its full cost on resale.
- Your roof needs work. Panels last decades. Installing them over a roof that needs replacing means paying to remove and refit them.
- You are almost entirely away during the day and have no storage. With a low self-consumption ratio, most generation is exported at the lower credited rate.
What solar does well
Against those cases, the situations where it is genuinely strong are equally specific: a high bill in an upper tariff slab, an unshaded roof with reasonable orientation, daytime occupancy or daytime industrial load, and an intention to keep the property.
There is also a component that does not appear in a payback calculation: a generation cost fixed at commissioning, against a grid tariff that only ever moves upward at the next TGERC or APERC order. For a business budgeting years ahead, that predictability has a value the payback number alone does not capture.
Next steps
If the case looks reasonable for your property, the sequence is: check what the PM Surya Ghar subsidy reduces your net cost to, estimate your generation and savings with the savings calculator, and read how on-grid systems work, since that is the configuration nearly all of this applies to.
Then book a survey. Nobody can tell you what your roof will generate without seeing it.
Common questions
What is the payback period for rooftop solar?
Payback is the time taken for cumulative savings to equal the net cost after subsidy. It is driven by four things: what the system costs you after subsidy, how much it generates where you live, what you currently pay per unit, and how much of the generation you use yourself rather than export. Because the tariff you avoid is your top slab rate, a high bill pays back faster than a low one.
Is solar worth it if my electricity bill is small?
Often not, and we will say so. Solar displaces units at your marginal tariff, so a household in a low consumption slab is avoiding a low rate, which stretches payback considerably. If your bill is modest and your supply is reliable, the honest answer may be that solar is not your best use of that capital.
How long do solar panels last?
Panels are typically warranted for performance over 25 years, degrading slowly rather than failing outright. The inverter has a shorter life than the panels and should be expected to need replacement once during that period, a cost worth including in any payback calculation that claims to be realistic.
Does solar increase property value?
A commissioned, well-documented system with transferable warranties is an asset a buyer can value, because it comes with a lower running cost. An undocumented installation of unknown provenance is harder to price and may be treated as a liability. Keeping the commissioning paperwork matters.
What ongoing costs does solar have?
Cleaning and periodic inspection, an eventual inverter replacement, and battery replacement if you have storage. These are modest against the savings but they are not zero, and a payback figure that ignores them is not a payback figure.
Find out whether it stacks up for your property
A free site survey gives you real numbers for your roof, your consumption and your tariff, not a national average.