The 200-Unit Trap: How to Right-Size Solar and Stay in the Cheap Protected Slab

• By Best Solar Company PK
• 23 Jul, 2026
• Buying Guide
• 8 min read

Pakistan's electricity tariff hides a trap that catches thousands of careful households every summer. Use 200 units in a month and you sit in the "protected" slab, paying Rs 10.54–13.01 per unit. Use just one more — 201 units — and your **entire** bill re-prices to the unprotected slab of Rs 22.44–28.91 per unit. One extra unit can more than double your bill, and the penalty follows you for six months.

With NEPRA's 2026 shift from net metering to net billing, exported solar now earns only about Rs 11 per unit. That changes the smartest way to use rooftop solar: instead of oversizing to sell power back, you right-size to keep your grid import under 200 units and stay in the cheap protected slab. Here's the math and the method.

Why 201 Units Costs Double 200

The protected slab is a subsidy for low-use domestic consumers — officially, anyone who has stayed at or below 200 units for the past six months. For FY 2025-26 (effective 1 July 2025), the rates are:

• **Protected:** 1–100 units at Rs 10.54, 101–200 units at Rs 13.01, plus a fixed charge of Rs 200–300/month.
• **Unprotected:** 1–100 units at Rs 22.44, 101–200 at Rs 28.91, 201–300 at Rs 33.10, plus Rs 275–400/kW in fixed charges.

Here's the cliff. A protected home using 200 units pays roughly Rs 2,355 in energy charges (100 × 10.54 + 100 × 13.01). Cross to 201 units and the whole bill jumps to the unprotected table: 100 × 22.44 + 100 × 28.91 + 1 × 33.10 ≈ Rs 5,168 — before fuel price adjustment, quarterly charges, TV fee and 18% GST. That's the same electricity, more than doubled, because you lost your category — not because you used one extra unit's worth of power.

To climb back into the protected slab you must again stay under 200 units for six straight months. That's why summer ACs are so dangerous: a single hot July can lock in expensive bills right through the new year.

Why Exporting Solar No Longer Pays

Under the old net-metering regime, surplus solar was swapped unit-for-unit or bought back at Rs 21–27. The NEPRA (Prosumer) Regulations 2026 replaced that with **net billing**: new rooftop installs export at roughly Rs 10–11.33 per unit (the National Average Energy Purchase Price), while every unit you import is still charged at your full retail slab. Surplus is now paid quarterly, on five-year contracts, and your system still can't exceed your sanctioned load.

The takeaway is blunt: a unit you export earns about Rs 11, but a unit you self-consume saves you Rs 22–29 (unprotected) or helps keep you protected. Selling to the grid is now the worst thing you can do with a solar unit.

The New Goal: Self-Consume Your Way Under 200

Your DISCO bills you on units **imported** from the grid. Solar power you use inside your home during daylight never passes through the meter as import — so it doesn't count toward your 200-unit slab. Right-sizing solar to shave daytime load does two things at once:

• **Replaces expensive units:** each self-consumed unit avoids a Rs 22–29 unprotected charge.
• **Re-prices the rest:** by pulling monthly import below 200, your remaining grid units drop from about Rs 25 to about Rs 12.

A household importing 380 units a month is deep in unprotected territory. Cover roughly 200 of those units with self-consumed solar and import falls to about 180 — back in the protected slab, with the leftover units now costing less than half.

How to Right-Size the System

Rules of thumb for Pakistan:

• **1 kW of panels generates about 4 units/day**, roughly 110–130 units/month (less in winter and monsoon).
• To cut 200 units of import you need about 1.7 kW of generation that you actually use during the day.
• Build in a margin for clouds and imperfect timing: a **2–3 kW system** is the sweet spot for a home hovering around 300–400 units.

The catch is timing. Solar only offsets load that runs while the sun is up. Shift your heavy chores — water pump, washing machine, iron, and especially daytime AC — into the 9am–4pm window. If your problem is evening consumption, a small lithium battery (for self-consumption, not export) stores midday surplus for after-Maghrib use and pushes import lower still.

### A Worked Example

A Lahore home uses about 380 units/month and pays unprotected rates. It installs a 3 kW on-grid/hybrid system for roughly Rs 400,000–500,000 and shifts daytime loads:

• Solar self-consumed: about 250 units/month.
• Grid import falls to about 130 units → **protected slab restored**.
• Saving on avoided unprotected units, re-priced remaining units and a lower fixed charge ≈ **Rs 8,000–10,000/month**.

At around Rs 100,000+ saved a year, payback lands near **four years** — and every year after is close to free power, with no reliance on an Rs 11 export cheque.

Zero-Export vs Net Billing

Here's a nuance worth confirming before you sign anything: many DISCOs place net-metered and net-billed consumers in a **separate tariff category**, which can itself strip protected status. If your whole goal is to stay protected, a **zero-export (self-consumption-only) system** — where the inverter is set never to push power to the grid — can be the cleaner route. You skip the Rs 60,000–80,000 net-metering application, avoid the Rs 11 export trap entirely, and keep your protected categorisation. Ask your installer and DISCO how a net-billing connection would change your slab before deciding.

Mistakes to Avoid

• **Oversizing to export.** At Rs 11/unit, extra panels you can't self-consume barely pay back.
• **Ignoring the six-month lock.** One careless AC-heavy month can cost you all winter.
• **Forgetting the meter reading date.** Spread heavy loads so no single billing cycle tips over 200.
• **Skipping load-shifting.** Panels without daytime usage just export cheaply.

Frequently Asked Questions

**Does solar self-consumption count toward my 200 units?** No. You're billed on what you import from the grid. Power your panels supply and you use on-site never registers as import, so it doesn't push you over the 200-unit protected threshold.

**I already have a 7-year net-metering agreement — should I switch?** No. Existing net-metering consumers keep their higher buyback (around Rs 22–27) until their contract expires. Net billing at Rs 11 applies only to new applications, so ride out your current agreement.

**How long until I get protected status back after crossing 200?** You must stay at or below 200 units for six consecutive months. Only then does your category revert and the cheaper Rs 10.54–13.01 rates return.

**Is a battery worth it just to stay protected?** Often yes, if your evening load is what tips you over 200. A small lithium battery shifts midday solar to the evening, cutting night-time import — far more valuable than exporting that surplus at Rs 11.

**What size system do I need?** For a home using 300–400 units, a 2–3 kW system with daytime load-shifting usually pulls import under 200. Match panel size to your daytime baseload, not your total bill.

Best Solar Company PK designs and installs reliable solar systems in Rawalpindi, Islamabad, Lahore, Multan, Taunsa Sharif and Karachi. Contact us for a free survey and the best advice for your home or business.