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Solar & UPS Calculator

Pick your appliances to get the inverter size, batteries for backup and solar panels you need.

  • Free
  • No sign-up
  • Runs in your browser: nothing is uploaded

1 Your appliances

Enter how many of each you have, the hours they run per day, and tick the ones that must keep running during load-shedding.

ApplianceWattsHow manyHours / dayOn backup

2 Backup and solar

What you need

Add your appliancesEnter how many fans, lights and other appliances you have to see the UPS, battery and solar size.

How the solar and UPS sizes are worked out

  • Inverter / UPS: the total power of everything on backup, plus room for the largest motor (fridge, pump) starting up, with a 25% safety margin.
  • Batteries: backup load × hours, allowing for inverter losses. Tubular batteries are sized to use only half their capacity (longer life); lithium uses 80%.
  • Solar panels: your daily electricity use divided by the useful sun hours where you live (about 4.5–5.5 hours in Pakistan), allowing 25% for heat, dust and wiring losses.

These are planning estimates to help you talk to installers and compare quotes. A qualified installer should check your wiring, roof and exact equipment before you buy.

Questions

Can a UPS run my AC?

An inverter AC needs a large inverter and battery bank to run on backup. It is usually more practical to run the AC on solar during the day, and keep fans, lights and the fridge on battery backup at night.

Tubular or lithium battery?

Tubular batteries cost less but are heavy, need water top-ups and last about 3–5 years. Lithium (LiFePO4) costs more but lasts much longer, needs no maintenance and can use more of its capacity.

How many units will solar save on my bill?

The "units per month" figure is your appliances' estimated use. A solar system of the size shown is designed to produce about that much on an average day. Actual savings depend on sun, season and whether you have net metering.