Stop paying for your roommate's electricity USAGE.
01 / 11 · The Problem
🌅 You leave for college at 8 AM. Your roommate stays back and runs the AC on full blast all day.
📋 At the end of the month, the hostel owner hands you a ₹1,200 electricity bill… and asks you to split it equally.
💸 You paid ₹600 for electricity you never used. You were in class!
02 / 11 · The Broken System
Owner walks around and notes the reading on each room's sub-meter.
Owner walks around again and notes the new reading.
Difference in units × price per unit = Total Bill for the room.
The total is split equally among all roommates, regardless of who used the AC, and for how long.
03 / 11 · The Solution
"What if the AC only charged you for the exact time YOU were in the room?"
A compact device installed near the AC switchboard. It measures electricity consumed, to the last watt, every single second.
Your digital wallet and remote control. Book the AC, watch your bill grow live, and split costs with roommates in real-time.
No more equal splits. No more arguments.
Just pay for exactly what you use.
04 / 11 · The App
Like Paytm. Add money to your in-app wallet. Your admin credits your account.
Choose how long you want to run it, or set a spending limit. The AC turns on automatically.
Done? End the session. The AC powers off and you only pay for what you actually used.
05 / 11 · The Magic
This is the feature that makes FairAC unique.
10:00 PM
Student A books the AC. Only Student A is paying.
11:00 PM
Student B arrives and taps "Join Session" on their app. Instantly, the bill splits 50/50 from this exact second.
12:00 AM
Student A has an early class. They end the session for themselves. They stop paying immediately. Student B continues alone.
02:00 AM
Student B ends the session. The AC turns off automatically.
06 / 11 · Safety & Trust
If the electricity goes out mid-session, the Smart Box saves your last reading — like a car's trip meter that doesn't reset. When power returns, it resumes from exactly where it left off.
All wallet transactions are locked and protected. No roommate can cheat, modify, or reverse a payment. Every action is permanently recorded in your history.
The system enforces a 3-minute safety wait before any new session can start. This protects the AC's compressor from damage — just like a trusted technician would recommend.
A physical Emergency Stop button is built into the Smart Box. Anyone can instantly cut the power to the AC in an emergency, without needing the app at all.
07 / 11 · Roles
08 / 11 · Comparison
| Feature | ❌ Old Sub-Meter System | ✅ FairAC |
|---|---|---|
| Tracking | Once a month | Live, second-by-second |
| Billing | Equal split (unfair) | Proportional to usage |
| Disputes | Monthly arguments | Zero. It's automatic. |
| Payment | Cash to owner | Digital wallet, in-app |
| Transparency | None | Full history in app |
| Access Control | None | App-protected Smart Box |
| Power Cut Safety | Data lost forever | Auto-recovers from backup |
09 / 11 · What's Next
The next version controls two rooms from a single Smart Box, cutting the installation cost per room by 50%. The owner saves money. Students benefit from lower prices.
Your roommate starts the AC. You get a notification. One tap on your phone screen — you're in, the bill splits. You never even need to open the app.
Future version will track the exact electricity used by each person even when the AC temperature changes. If you ran it at 16°C and your roommate ran it at 26°C, each pays for exactly the electricity their setting consumed.
11 / 11 · Thank You
A fully functional system with real hardware, a live mobile app, and a cloud backend — built during a Summer Internship in 2026.
Questions?