Home Energy Savings Power & Emergency Prep Backup Power Chatbot Dashboard

Backup Power & Battery Calculator

Pick what you need to run during an outage. We size for both the power it draws continuously and the extra jolt motors need when they start.

Your existing backup equipment

These values are shared with the Power & Emergency Preparedness page.

Generator size

Solar / inverter size

Usable battery storage

kWh

What do you need to run?

Select appliances, then set how many you have and how many hours a day each one runs during an outage.

Use actual nameplate ratings

Turn this on to type the running and starting watts printed on your appliance labels instead of using our typical values.

Essentials

Refrigerator180 W run · 900 W start

How many

Hours per day

Freezer250 W run · 1,100 W start

LED lights100 W run

How many

Hours per day

Fan80 W run · 200 W start

How many

Hours per day

Phone chargers50 W run

How many

Hours per day

Wi-Fi router20 W run

How many

Hours per day

Medical device400 W run · 600 W start

Cooling

Small AC unit (window)1,500 W run · 3,600 W start

Large split AC unit3,500 W run · 8,000 W start

Central air conditioner4,500 W run · 11,000 W start

Comfort & other

Dehumidifier500 W run · 1,500 W start

Electric water heater4,000 W run

Laptop / TV250 W run

Kitchen

Microwave1,200 W run · 1,500 W start

Electric kettle1,500 W run

Electric stove (one burner)2,500 W run

Coffee maker900 W run

Dishwasher (heated dry)1,500 W run · 2,200 W start

Laundry

Washing machine500 W run · 1,400 W start

Electric dryer3,000 W run · 4,000 W start

Iron1,200 W run

Pumps & motors

Water pump (1/2 HP)750 W run · 2,100 W start

Well pump (1 HP)1,000 W run · 3,000 W start

Sump pump (1/3 HP)600 W run · 1,800 W start

Pool pump1,000 W run · 2,500 W start

Air compressor (small)1,000 W run · 3,000 W start

Garage door opener550 W run · 1,600 W start

Safety margin / headroom

Inverter / conversion losses

% loss

Battery reserve

Safety disclaimer: Smart Power AI is a planning assistant. All figures are estimates. Verify electrical, generator, medical and emergency decisions with qualified professionals and official agencies.

Privacy: Bill uploads may contain personal information. Smart Power AI extracts only energy information for your report and masks your account number.