Battery Backup Calculator

Calculate how long battery storage can power your essential loads during outages. See costs with Illinois Smart Inverter rebates included.

Battery Configuration
1 Powerwall (13.5 kWh)3 Powerwalls (40.5 kWh)

Tesla Powerwall 3 - Most popular choice for Chicago homes

Essential Loads

Select the appliances you want to keep running during a power outage:

Refrigerator

150W × 24h/day

3.6 kWh/day

Furnace Blower

600W × 8h/day

4.8 kWh/day

LED Lights (10)

100W × 6h/day

0.6 kWh/day

WiFi Router

20W × 24h/day

0.5 kWh/day

Phone Charging

25W × 4h/day

0.1 kWh/day

Sump Pump

800W × 2h/day

1.6 kWh/day

Microwave

1000W × 0.5h/day

0.5 kWh/day

TV

150W × 4h/day

0.6 kWh/day

Laptop

65W × 8h/day

0.5 kWh/day

Garage Door

500W × 0.1h/day

0.1 kWh/day