RSK Solar Energy

Solar calculator for Punjab

Size, PM Surya Ghar subsidy, cost after subsidy and payback, worked out from your PSPCL bill with the FY 2026-27 tariff and Punjab's free-units rules. No phone number needed to see the result.

What do you want to enter?
Home bills from PSPCL usually cover two months. Enter the figure as printed.
The bill covers
Printed on your bill. A subsidised system cannot be larger than this — we need it to size correctly.
System type
Not sure? Choose on-grid. How the three differ
Free-units category
Above 300 units a month, general-category homes pay for every unit. The other categories pay only for units above 300.
More details (optional)
Shade-free area. About 100 sq ft per kW.

Example: a home using 900 units on a two-month bill. Enter your own figures above.

How the calculator works it out

  1. Your units. If you enter a rupee amount, it walks the PSPCL tariff backwards, taking off fixed charges and duty, to find the units. Entering the units from your bill is more accurate.
  2. The free-units test. A home at or under 300 units a month already pays nothing. You get an honest answer instead of a savings figure.
  3. The size. For homes over the line, it finds the smallest system that brings your net units under 250 a month, leaving headroom for summer, and compares it with the size that would cover all your use. Businesses are sized to cover their use.
  4. The limits. The system is capped at your sanctioned load, which the calculator asks for directly, and at your roof area if you enter it.
  5. The subsidy. PM Surya Ghar applies to homes and housing societies with on-grid systems. If a rule rules you out, it tells you which one.
  6. The saving. Your bill before and after solar, from the same tariff, including the free-units cliff, fixed charges and duty. Payback is the cost after subsidy divided by the yearly saving.

Assumptions, shown rather than hidden

  • 1,530 units per kW per year, less a 20% allowance for heat, dust, wiring and inverter losses: 1,224 units per kW per year.
  • Tariffs rise 3% a year and panels lose 0.5% of output a year, for the 25-year saving.
  • PSPCL applies the 300 free units to your net units after solar. We confirm this for your connection before quoting.

The tariff it uses

General-category homes over 300 units pay energy charges on every unit. Reserved categories (SC, BC, non-SC BPL, Freedom Fighter) pay only for units above 300.

PSPCL domestic tariff, FY 2026-27
Sanctioned load Units ₹ per unit Fixed, ₹ per kW a month
Up to 2 kW First 300 units 3.85 50
Above 300 units 7.05
2 to 7 kW First 300 units 4.25 70
Above 300 units 7.05
7 to 20 kW First 300 units 5.00 100
Above 300 units 7.05

Effective 01.04.2026 to 31.03.2027. Electricity duty of about 13% is added on top. Always check the figures against your own bill.

Net metering in Punjab, briefly

An on-grid system is connected through a bi-directional net meter fitted by PSPCL. It records the units you draw from the grid and the units your roof exports. You are billed on the difference.

In Punjab a rooftop system can be up to 100% of your sanctioned load. Exported units are settled under PSERC's net metering rules and are worth less than the units you use yourself, so the calculator gives surplus exports no value. That keeps the estimate on the safe side and is another reason not to oversize.

Documents to keep ready

  • A recent electricity bill with your consumer number and sanctioned load
  • Aadhaar card and proof of ownership of the house
  • A bank account in the applicant's name, with passbook or cancelled cheque

The full process, and the mistakes that get applications rejected, are in the PM Surya Ghar subsidy guide.

Standard sizes at a glance

Standard rooftop system sizes with generation, roof area, subsidy and price
System Units a month Roof area Home subsidy After subsidy Zero bill for homes using up to
1 kW system on-grid not offered this small 102 100 sq ft ₹30,000 ₹55,000 – 65,000 352 units
2 kW system on-grid not offered this small 204 200 sq ft ₹60,000 ₹1,10,000 – 1,30,000 454 units
3 kW system 306 300 sq ft ₹78,000 ₹1,02,000 – 1,20,000 556 units
5 kW system 510 500 sq ft ₹78,000 ₹1,97,000 – 2,22,000 760 units
10 kW system 1,020 1,000 sq ft ₹78,000 ₹4,72,000 – 5,22,000 1,270 units

Generation at 1,224 units per kW per year, after losses. Zero-bill figures assume a general-category home and that PSPCL applies the 300 free units to net units.

Estimated price range. Prices are indicative and subject to change. Contact us for the latest pricing and a customised quotation.

Questions we are asked

Is my bill really zero if I use under 300 units a month?

Yes, for homes using electricity for residential purposes. Punjab gives 300 free units a month (600 on a two-month bill), with no energy charges, fixed charges, meter rent or government levies. That is why the calculator will not show you a payback figure if you are under the line: there is no bill for solar to reduce.

Why does the calculator recommend a smaller system than other quotes?

Because of the free-units rule. A general-category home over 300 units pays for every unit. Once solar brings the net units under 300, the bill is already zero, so capacity beyond that adds almost nothing to your saving. The calculator shows both figures: the size that takes your bill to zero, and the size that would cover all of your use.

Does the subsidy reduce the price I pay the installer?

No. You pay the full system cost. The PM Surya Ghar subsidy is credited to your bank account 30–45 days after PSPCL inspects the system.

What is sanctioned load and where do I find it?

The maximum load your connection is approved for, in kW. It is printed on your PSPCL bill. A rooftop system cannot be larger than your sanctioned load, so the calculator caps the system at it and tells you if you need load enhancement first.

How accurate is the estimate?

It is a first estimate, and it tells you what it assumed. Units entered from your bill are exact; an amount in rupees is converted to units using the PSPCL tariff and is an estimate. Generation depends on roof direction and shading, which only a site survey can confirm. Where a figure is uncertain, the calculator shows a range.

Do I have to give my phone number to see the result?

No. The full result is shown to everyone. If you want to discuss it, the WhatsApp button sends us the figures so you do not have to repeat them.