---
title: "WattEY Sub-Billing — Fair electricity bills for shared buildings"
headline: "WattEY Sub-Billing: split one electricity bill fairly"
description: "WattEY Sub-Billing by Ali Ahmed: residents share measured room usage by stay dates, with meter photos, departure bills and tracked balances."
canonical_url: https://alioahmed.com/work/electricity-sub-billing
type: case-study
role: "Head of Energy Systems & Product Engineering"
date_label: "Live since October 2026 · first building"
status: live
date_modified: 2026-10-27
author:
  name: "Ali Ahmed"
  url: https://alioahmed.com/
  orcid: https://orcid.org/0009-0007-4265-3295
key_figures:
  - "265 beds running on WattEY Sub-Billing at Rehma Hostel, Lahore"
  - "Clear balances billed, paid and still owed—not guaranteed collection"
  - "Photo proof behind every meter reading and every bill"
entities:
  - name: "WattEY Sub-Billing"
    type: SoftwareApplication
  - name: "Wattey Energy"
    type: Organization
    url: https://watteyenergy.pk/
    same_as:
      - https://bijlibachao.pk/
  - name: "Shared electricity billing, explained"
    type: DefinedTermSet
person_same_as:
  - https://www.linkedin.com/in/alioahmed/
  - https://github.com/alioahmed
  - https://orcid.org/0009-0007-4265-3295
  - https://x.com/Alioahmed_
  - https://about.me/alioahmed
  - https://dev.to/alioahmed
  - https://medium.com/@alioahmed
  - https://hashnode.com/@alioahmed
  - https://substack.com/@alioahmed
  - https://huggingface.co/alioahmed
  - https://bsky.app/profile/alioahmed.bsky.social
  - https://mastodon.social/@alioahmed
  - https://www.kaggle.com/alioahmed
  - https://www.producthunt.com/@alioahmed
  - https://www.patreon.com/cw/alioahmed
  - https://www.goodreads.com/user/show/202106301-ali-ahmed
  - https://fueler.io/alioahmed
  - https://gitlab.com/alioahmed
  - https://linktr.ee/alioahmed
  - https://topmate.io/alioahmed
related:
  - https://alioahmed.com/work/wattey
  - https://alioahmed.com/work/wattey-metering
  - https://alioahmed.com/work/sts
  - https://alioahmed.com/work/solar-performance-cloud
  - https://alioahmed.com/work/bijli-bachao
full_corpus: https://alioahmed.com/llms-full.txt
site_index: https://alioahmed.com/llms.txt
---

# WattEY Sub-Billing — Fair electricity bills for shared buildings

> WattEY Sub-Billing shares a room’s measured electricity charge between residents for their recorded occupancy dates. Ali Ahmed designed and built it at Wattey Energy (formerly BijliBachao.pk), with photographs supporting the readings, departure bills and unpaid-balance tracking. It has been live at Rehma Hostel, a 265-bed hostel in Lahore, since October 2026: 7 floors, 94 rooms and about 160 meters. Its first real billing month is in progress.

**Canonical URL:** https://alioahmed.com/work/electricity-sub-billing  
**Role:** Head of Energy Systems & Product Engineering — Live since October 2026 · first building  
**Summary:** WattEY Sub-Billing by Ali Ahmed: residents share measured room usage by stay dates, with meter photos, departure bills and tracked balances.

## Key figures

- **265 beds** — running on WattEY Sub-Billing at Rehma Hostel, Lahore
- **Clear balances** — billed, paid and still owed—not guaranteed collection
- **Photo proof** — behind every meter reading and every bill

### What WattEY Sub-Billing is.

WattEY Sub-Billing shares a room’s measured electricity charge between residents for their recorded occupancy dates. Ali Ahmed designed and built it at Wattey Energy (formerly BijliBachao.pk), with photographs supporting the readings, departure bills and unpaid-balance tracking. It has been live at Rehma Hostel, a 265-bed hostel in Lahore, since October 2026: 7 floors, 94 rooms and about 160 meters. Its first real billing month is in progress.

Rooms are metered, not individual people or appliances. A resident receives a share of the room’s usage for their recorded stay; this does not measure their personal consumption or automatically detect time away during an active stay.

### Splitting the electricity bill is where the arguments start.

You pay one electricity bill, then collect it back from everyone inside, and they don’t all stay the whole month. Residents say “I wasn’t even here for 10 days”, “I’m leaving today, what do I owe?”, “Why is my bill more than his?” and “This can’t be my usage.”

Splitting equally means someone who was away pays the same as someone who ran the AC all night. Spreadsheets are slow, mistakes go unnoticed, and there is nothing to show when someone disputes a figure. And when rent comes in but the electricity money doesn’t, you cover the gap yourself.

### What you get as the owner.

- See the recovery gap — Compare the utility bill, resident charges, receipts and your own common-area use. Identify what is still owed rather than assuming every billed amount has been collected.
- Keep dues visible — Unpaid balances remain attached to the resident’s account, including after a room change, so staff have a record to follow up.
- Show the reading behind the charge — The move-in record includes the room’s starting reading and photograph. When a charge is questioned, there is evidence to review.
- Prepare bills in one workflow — Staff photograph the meters on their phone. Every bill in the building is ready in one go, printable with the photos on it.
- You stay in control — Staff only see what they need. Nobody can quietly edit a bill, and every change is logged.

### How it works.

- 1. Set up your building — Add floors, rooms, beds and meters once, including your own offices and common areas.
- 2. Check people in — Pick a free bed. Your warden gets a job on their phone to photograph that room’s meters: the new resident’s starting reading.
- 3. Read the meters monthly — The app walks staff floor by floor, even without signal. You check every photo and ask for a retake if one is unclear.
- 4. Bill and collect — Bills split each room fairly by the days people stayed. Track who paid, who didn’t, and what is still owed.
- 5. Settle leavers on the spot — Someone leaving gets their exact bill that day. Each month closes against your electricity bill, then locks.

### Fair bills, built on proof.

I built the reading-to-bill workflow around occupancy changes, photographic evidence and a clear record of charges. The room’s measured usage is shared—not separately measured for each person.

- A charge for the recorded stay — Move-in and departure readings define the stay. Within a shared room, the charge is shared by occupancy—not by measuring each person’s appliances.
- The reading stays with its photo — Each bill carries the room’s reading evidence, so the resident and office can review the source of the charge.
- A final bill at departure — Prepare the departing resident’s bill that day. Any amount not paid remains a recorded balance; generating the bill does not itself settle the debt.
- Usage and payment are separate records — Check the room’s usage shares separately from billed amounts, receipts, arrears and the owner’s own areas.
- Room changes keep their history — Move-in, departure and room-change records keep each stay and its charges attributable to the resident.
- Corrections leave a trail — Issued bills and payments retain their history. Authorised corrections and reversals are recorded rather than silently replacing the original record.

### From move-in to move-out, everything on paper.

Shown on the page from WattEY Sub-Billing’s own document templates, with made-up demo data:

- Move-in record — the meter readings on the day someone moves in, with photos. Their bill starts from these numbers.
- Photos on the bill — every reading on the bill is printed with the photo it came from and when it was taken.
- Move-out bill — someone leaving gets their exact share that day.

### The office and field application.

A web dashboard for occupancy, bills, payment records and the monthly comparison with the utility bill. Rooms can have two meters, one or none; common areas and a separately billed commercial unit stay identifiable.

An Android app for photographing meters and entering readings, including where there is no signal. Captures queue for upload and review when the connection returns.

Before any resident got a real bill, every calculation was checked against 840 test bills worked out independently, and all of them matched; a full backup was restored with every record intact; and the system was security-tested (as of 12 October 2026).

### Running in a real building today.

WattEY Sub-Billing runs at Rehma Hostel, a 265-bed hostel in Lahore, with 7 floors, 94 rooms and about 160 meters: shared rooms, single apartments, offices, common areas and a café on its own rate. The office uses a web dashboard; staff read meters with an Android app that works without signal.

### When people see their usage, they use less.

In a study of a Toronto apartment building, residents used about 20% less electricity once they paid for their own usage. Meters and billing cost money too, so think of it as fairness that also nudges people to save, not a guaranteed discount. Source: Dewees & Tombe, Canadian Public Policy, 2011 (https://www.trevortombe.com/publication/submeters/).

### Who it is for.

The documented deployment is a hostel. Other shared buildings have related billing needs, but each requires its own meter, occupancy and billing-rule assessment. Category references below establish related problems, not additional WattEY Sub-Billing deployments. Other settings are potential adaptations; EV charging would also require charger or session integration, which this case does not demonstrate.

- Documented setting: Run a hostel or PG? Share each room’s measured electricity charge between its residents for their recorded stay dates, with meter photographs supporting the readings.
- Potential adaptation: Manage student housing? Give students a clear account of their share of a room’s measured usage, with the meter photograph behind the reading.
- Potential adaptation: Run co-living spaces? Make each resident’s share explainable with occupancy dates, meter readings and photographs.
- Potential adaptation: Rent out homes on Airbnb or for monthly stays? See what each stay really cost you in electricity, so you can price it right or set a fair cap. For monthly and direct bookings, charge guests for what they actually used, with the meter photographed at check-in and check-out. (On Airbnb itself, utility fees have to be shown in the price up front.)
- Potential adaptation: Offer serviced or long-stay apartments? Give guests on longer stays a clear electricity line on their bill, backed by a meter reading they can check.
- Documented setting: House staff or workers? Know what each company or team used and charge it back fairly. WattEY Sub-Billing already does this for a company renting rooms for its staff in its first building.
- Potential adaptation: Own a building on one electricity connection? Charge each flat for its own usage instead of dividing the total by size or headcount.
- Documented setting: Got a shop or café under the same roof? It pays its own rate on its own meter, without changing anyone else’s share.
- Potential adaptation: Share power with people who come and go? A related shared-supply problem, not a demonstrated WattEY Sub-Billing deployment. Site metering, billing rules and any charger/session integrations require separate validation.

### Who uses it in your building.

- Owner — Sees and controls everything, including rates and reopening a closed month.
- Manager — Runs the building: rooms, residents, check-ins, closing the month.
- Accountant — Bills and payments. Can’t change the building’s setup.
- Warden — Front desk: checks people in and out. No access to money.
- Meter reader — Photographs meters on the phone. Sees no money and no resident details.

### Is WattEY Sub-Billing right for your building?

- One electricity connection, with meters in the rooms or units (or space to add them)
- People who move in and out during the month
- Shared rooms, single apartments, offices or shops under one roof
- You want to know each month whether you got back what you paid
- Today: Electricity only: rent and deposits stay in your existing system
- Today: Office dashboard on the web, meter-reading app on Android
- Today: Payments are recorded when taken in person; no online payments yet
- Today: Offline photo capture and operator-entered readings, queued for later upload

### You recover your cost. You don’t resell electricity.

WattEY Sub-Billing splits the bill your building actually received. You don’t set your own electricity rate or add a margin; each person simply sees their fair share of a real bill.

### Where it stands.

Live in its first building since October 2026, with the first real billing month in progress. It is not yet running in multiple buildings.

## FAQ

### Does offline capture mean automatic offline meter recognition?
Offline capture stores photographs and operator-entered readings for later upload. It does not mean the app recognises digits without a connection. Automatic recognition is not claimed as an enabled feature by this case study.

### What is WattEY Sub-Billing?
Electricity billing software for buildings where many people share one connection. It turns the building’s one electricity bill into a fair bill for each person, based on their room’s usage and the days they stayed, with a photo of the meter as proof.

### How do I split one electricity bill fairly between residents?
Measure, don’t guess. Read each room’s meter with a photo, split the room’s usage between the people who occupied it by their recorded stay dates. Compare the resulting charges and payments with the utility bill separately, including common-area use and unpaid balances. Billing is not guaranteed collection.

### How is someone billed if they move in or out in the middle of the month?
Their bill starts or ends on the exact day, from the meter reading taken when they arrived or left. They never pay for electricity used before they arrived or after they left.

### Can someone’s final bill be ready on the day they leave?
Yes. Photograph the room’s meters at departure and prepare the resident’s final bill that day. Payment must still be collected; any unpaid amount remains a recorded balance.

### Why not just split the bill equally?
A building-wide split by headcount or area (sometimes called RUBS) does not reflect each room’s metered usage or changes in its occupancy. WattEY Sub-Billing shares measured room usage by recorded stay dates; it does not separately measure roommates’ appliances or automatically detect an absence during an active stay.

### Does every resident need their own meter?
Rooms are metered, not individual people or appliances. A resident receives a share of the room’s usage for their recorded stay; this does not measure their personal consumption or automatically detect time away during an active stay.

### What if a resident says their bill is wrong?
Show them the bill. It lists the days they stayed, the meter readings and a photo of every meter. If a reading needs checking, the office can ask for a new photo.

### How do I know I got back what I paid the electricity company?
Each month WattEY Sub-Billing puts what you paid the electricity company next to what residents were billed and what your own offices and common areas used, before the month is locked.

### Can a bill be changed after it is issued?
Not quietly. Bills and payments are locked once made. Any correction is recorded with a trail.

### What kinds of buildings is WattEY Sub-Billing for?
The documented deployment is a hostel. Other shared buildings have related billing needs, but each requires its own meter, occupancy and billing-rule assessment. Category references below establish related problems, not additional WattEY Sub-Billing deployments. Other settings are potential adaptations; EV charging would also require charger or session integration, which this case does not demonstrate.

### Can Airbnb hosts use WattEY Sub-Billing?
Yes, to see what each stay really cost in electricity and price it right or set a fair cap. On Airbnb itself, utility fees must be shown in the price up front, so charging a guest for usage after they leave isn’t allowed there. For monthly and direct bookings, you can charge for what the guest actually used, with the meter photographed at check-in and check-out.

### What do I need to get started?
One electricity connection with meters in the rooms or units, your building’s rooms and beds set up once, and an Android phone for whoever reads the meters. WattEY Sub-Billing handles electricity only; rent and deposits stay in your current system.

### Who in my building uses it?
The owner, manager, accountant and front desk use the web dashboard; staff who read meters use the Android app. Each person sees only what they need, and the meter reader never sees money or resident details.

### Is WattEY Sub-Billing reselling electricity?
No. It splits the bill your building actually received, at cost. You don’t set your own electricity rate or add a margin.

### Who built WattEY Sub-Billing?
Ali Ahmed, Head of Energy Systems & Product Engineering at BijliBachao.pk, designed and built it: the billing, the office dashboard and the meter-reading app.

### Is WattEY Sub-Billing live?
Yes, in its first building: Rehma Hostel, a 265-bed hostel in Lahore, live since October 2026, with its first real billing month in progress. It is not yet running in multiple buildings.

---
Rendered from the structured content at https://alioahmed.com/work/electricity-sub-billing. Facts trace to the canonical bio; render, don't reword.