Water Heater or Geyser have star rating based on standing loss which is the based on the mount of electricity consumed in kwh for every 24 hour to maintain the temperature at optimum 45°C of water for specific capacity of geyser water heater. Below table will help you find the difference between a 4 star and 5 star water heater geyser.
| Standing Loss (kWh/24 hour/45°C) | 1 star Geyser | 2 star Geyser | 3 star Geyser | 4 star geyser | 5 star geyser |
| 06 Liters Geyser | ≤0.426 &> 0.387 | ≤0.352 &> 0.320 | ≤ 0.320 &>0.291 | ≤ 0.291 &> 0.265 | ≤ 0.265 |
| 10 Liters Geyser | ≤0.485 &> 0.441 | ≤0.441 &> 0.401 | ≤ 0.401 &>0.365 | ≤ 0.365 &> 0.332 | ≤ 0.332 |
| 15 Liters Geyser | ≤ 0.558 &> 0.507 | ≤0.507 &> 0.461 | ≤ 0.461 &> 0.419 | ≤ 0.419 &> 0.381 | ≤ 0.381 |
| 25 Liters Geyser | ≤0.680 &> 0.618 | ≤0.618 &> 0.562 | ≤ 0.562 &>0.511 | ≤ 0.511 &> 0.465 | ≤ 0.465 |
| 35 Liters Geyser | ≤0.777 &> 0.706 | ≤0.706 &> 0.642 | ≤ 0.642 &>0.584 | ≤ 0.584 &> 0.531 | ≤ 0.531 |
| 50 Liters Geyser | ≤0.898 &> 0.816 | ≤0.816 &> 0.742 | ≤ 0.742 &>0.675 | ≤ 0.675 &> 0.614 | ≤ 0.614 |
| 70 Liters Geyser | ≤ 1.019 &> 0.926 | ≤0.926 &> 0.842 | ≤ 0.842 &> 0.766 | ≤ 0.766 &> 0.697 | ≤ 0.697 |
| 100 Liters Geyser | ≤1.164 &> 1.058 | ≤1.058 &> 0.962 | ≤ 0.962 &> 0.875 | ≤0.875 &>0.796 | ≤ 0.796 |
| 150 Liters Geyser | ≤1.310 &> 1.191 | ≤1.191 &> 1.083 | ≤ 1.083 &> 0.985 | ≤ 0.985 &> 0.896 | ≤ 0.896 |
| 200 Liters Geyser | ≤1.456 &> 1.323 | ≤1.323 &> 1.203 | ≤ 1.203 &> 1.088 | ≤ 1.088 &> 0.984 | ≤ 0.984 |
I guess for average household Storage water heater capacity of more than 50L won’t be needed. Even 35L & 50L is a rarity for most households. 50L & above geyser capacity is more suitable for commercial establishment.