What size inverter do I need?
Inverter and battery for common Indian homes and loads, from a 1 BHK flat to running an AC.
- Typical appliance watts
- Battery for 2 to 8 hours
Inverter size by home
| Home or load | Running load | Inverter | Battery for 4 hours |
|---|---|---|---|
| 1 BHK home | 276 W | 650 VA | 1 × 150 Ah tubular |
| 2 BHK home | 519 W | 900 VA | 1 × 260 Ah tubular |
| 3 BHK home | 671 W | 1050 VA | 2 × 165 Ah tubular |
| 4 BHK or independent house | 978 W | 2000 VA | 2 × 260 Ah tubular |
| Refrigerator | 168 W | 650 VA | 1 × 100 Ah tubular |
| 1 HP water pump | 768 W | 1500 VA | 2 × 200 Ah tubular |
| Air cooler | 466 W | 750 VA | 1 × 230 Ah tubular |
| Work from home | 303 W | 650 VA | 1 × 150 Ah tubular |
| Small shop | 390 W | 650 VA | 1 × 200 Ah tubular |
| 1.5 ton AC | 1518 W | 3200 VA | 3 × 260 Ah tubular |
Questions
How is the inverter size worked out?
Running watts × 1.25 for a safety margin ÷ 0.8, the power factor Indian brands rate their inverters at. Then we pick the next standard size. Motors such as a fridge or pump also need starting surge, which we check against the inverter’s rating.
Why do the hours change the battery but not the inverter?
The inverter sets how much can run at once; the battery sets for how long. Longer backup needs more Ah, and past what one 12 V battery can give, a 24 V inverter with two batteries.
Will this raise my electricity bill?
Yes, a little. The battery is recharged from the grid after every cut, with some loss, and the inverter draws standby power all day. Each page shows the units a month; the calculator prices them at your state’s slabs.