Calculator
Appliance Load Calculator
If you do not know your monthly units, work it out from your appliances. Add them up and get your usage plus the solar size you need.
The formula
What this assumes
- Fridge runs all day but the compressor cycles on and off. We count about 8 effective hours.
- AC power use changes with room temperature and setting. Inverter ACs use much less.
- Wattage varies by model. Check the label on your appliance for the exact number.
- Fixed charges on your bill do not go away with solar.
- Actual usage changes a lot between summer and winter.
Common questions
How many units does an AC use?
A 1.5 ton AC running 8 hours uses about 12 units a day, so around 360 units a month. This one appliance is usually more than everything else combined.
My bill does not show units. What do I do?
Look for kWh or units consumed. If it really is not there, use this calculator to estimate from your appliances, or divide your bill amount by your state per unit rate.
Why is my actual bill higher than this calculation?
Fixed charges, meter rent, electricity duty and slab based tariffs. As you use more units, the rate per unit also goes up in most states.
Should I size solar for summer or average usage?
Average, usually. Sizing for peak summer means you generate excess for eight months of the year, and depending on your state you may not get paid well for that excess.