Case Study

Shah Alam,
Selangor

TNB Bill

RM671.50 → RM99.35

Item

Value

Location (general)

Shah Alam, Selangor

Bill comparison months

Nov–Dec 2024 vs Mar 2026

Before total bill

RM671.50

After total bill

RM99.35

Tariff shown on bill

A: Kediaman (before) / Domestik Am (after)

Important note

Before bill includes previous balance RM301.95

The Homeowner's Situation Before vs. After Solar

This homeowner wanted to bring down a very high monthly electricity bill with solar panels for house installations while reducing exposure to ongoing electricity costs.

Before Solar

What the Bill Showed

Billing period: 09.11.2024–08.12.2024 (30 days)
Total bill amount: RM671.50
Key lines (Ringkasan Bil Anda):
- Baki terdahulu: RM301.95
- Caj Semasa NEM: RM369.55
- Pelarasan Penanggenapan: RM0.00

After Solar

What changed

Billing period: 01.03.2026–31.03.2026 (31 days)
Total bill amount: RM99.35
NEM shown on bill: Yes (bill shows “Caj Semasa NEM”)
Key lines (Ringkasan Bil Anda):
- Caj Semasa NEM: RM99.33
- Pelarasan penggenapan: RM0.02
- Baki terdahulu: RM0.00

How To Interpret This Result?

Previous Balance Effect (Why RM671.50 Is “Not Clean”)

Baki terdahulu = RM0.00

Baki terdahulu (previous balance): RM301.95 – This is old unpaid money carried forward from earlier months.
Caj semasa (current month charges): RM369.55 – This is the actual cost of electricity for that month’s billing period.

Baki terdahulu = RM0.00

RM671.50 (before total) vs RM99.35 (after total)

…it’s not apples-to-apples, because the “before” month includes an extra RM301.95 that isn’t part of that month’s usage.

Baki terdahulu = RM0.00

Before (current charges): RM369.55
After (current charges, NEM): RM99.33

This isolates the monthly electricity charges and removes the “debt repayment” effect.

Billing Days Differ (30 vs 31): Why We Use Per-day

The two bills cover different lengths:

Before: 30 days
After: 31 days

Even if daily usage stayed identical, the 31-day bill would naturally be higher just because it covers one more day.

That’s why we normalize to per day:

Before RM/day (total): 671.50 ÷ 30 = RM22.38/day (but inflated by previous balance)
Before RM/day (current charges only): 369.55 ÷ 30 = RM12.32/day
After RM/day: 99.35 ÷ 31 = RM3.20/day

What this tells the reader:

The cleanest “daily cost” comparison is: RM12.32/day → RM3.20/day

Tariff Label Changed (A: Kediaman → Domestik Am): What It Implies

The bill shows different tariff wording in different years. This can happen because:

TNB bill layout changes over time, and/or
Tariff categorization/label presentation changes (even if you’re still residential

Why you mention it (credibility + fairness): If tariff calculation rules changed between 2024 and 2026, then RM savings isn’t purely “solar effect”—some part could be tariff differences.

So your case study should say: