Typical Appliance Wattages in Indian Homes
| Appliance | Typical Wattage | Daily Use | Daily Units |
|---|
| Ceiling fan | 75 W | 12 hrs | 0.9 |
| LED lights (8) | 80 W | 6 hrs | 0.5 |
| Refrigerator | 150 W (running) | 8 hrs compressor | 1.2 |
| LED TV | 100 W | 6 hrs | 0.6 |
| 1.5 ton inverter AC | 1,200 W | 8 hrs | 9.6 |
| Washing machine | 500 W | 1 hr | 0.5 |
| Geyser | 2,000 W | 30 min | 1.0 |
| EV charger (home) | 3,000 W | 3 hrs | 9.0 |
Notice how ACs and EV chargers dominate: one 1.5 ton AC uses more energy than the rest of a typical home
combined. Load calculation matters most for exactly these homes.
Connected Load vs Daily Consumption
Two numbers come out of a load calculation and they answer different questions. Connected load
(watts) is everything that could run at once; it sizes your inverter and backup. Daily
consumption (kWh) is energy actually used; it sizes your solar array. A home can have a 4 kW connected
load but only 8 kWh daily consumption, needing just a 2 kW solar system with a 5 kVA inverter. Size the
inverter precisely with the solar inverter size calculator and
batteries for the backup share of the load with the
solar battery calculator.
Before You Add Appliances: Count What Actually Runs
The two easiest ways to wreck a load calculation are counting nameplate watts and counting ownership instead
of usage. A fridge is plugged in 24 hours but compresses about 8; an inverter AC rated 1,500W averages nearer
1,200W once the room cools; a geyser runs 30 minutes, not the whole morning. The defaults in this tool already
use these effective figures, so resist the urge to "correct" them upward. Do the opposite check instead: walk
through an actual weekday evening and note what runs simultaneously, because that simultaneous figure,
not the sum of everything you own, is what sizes the inverter.
Worked Example: A Patna Household, Appliance by Appliance
A Patna home runs 3 fans (12 hours each), 6 LED lights (6 hours), a fridge, a TV (5 hours) and one 1.5 ton
inverter AC for 6 summer hours. Connected load: about 1,735W. Daily energy: roughly
12 kWh, of which the AC alone is 7.2. That is ~359 units a month, pointing to a
3.5 kW solar system and a 3,500 VA inverter (the AC plus fridge starting
together is the sizing event). Note how one appliance dominates: remove the AC and the same home needs barely
1.5 kW, which is why load calculation beats guessing.
Turning Your Load Numbers Into a System
- Monthly units → system size: carry the monthly figure into the
system size calculator with your real city for an exact kW.
- Connected load → inverter: the simultaneous-run subset of your load sizes the inverter in
the inverter size calculator.
- Backup subset → battery: mark what must survive a power cut and size storage for only
that subset in the solar battery calculator; whole-home backup
triples battery budgets.
- Future loads now: add the planned EV or second AC today; retro-fitting capacity costs
more than provisioning it.
Load Calculation Mistakes
- Using nameplate watts for compressor appliances. It double-counts ACs and fridges and
oversizes everything downstream by 30 to 50%.
- Forgetting the pump. A 750W water pump running an hour a day is invisible until the
borewell runs during a power cut on an undersized inverter.
- Averaging away summer. If the AC runs 10 hours in May and 0 in December, size energy for
the year but the inverter for the May evening.
- Adding "someday" appliances everywhere. Provision future loads in the array, but sizing
the battery for a hypothetical second AC wastes ₹50,000 today.
How This Load Calculator Works
Connected load (W) = Σ Quantity × Wattage
Daily units (kWh) = Σ Quantity × Wattage × Hours ÷ 1000
Solar kW = Monthly units ÷ (4.8 sun hrs × 30 × 0.8)
Assumptions
- Wattages: realistic running averages; compressor appliances (AC, fridge) use effective
duty-cycle figures rather than nameplate peaks
- Sun hours: a 4.8-hour planning value; for city-specific sizing continue to the
system size calculator
- Inverter: load ÷ 0.8 power factor with 20% headroom, rounded up to standard VA ratings
