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An Unbound Renewable Energy Company
Open Mon-Fri: 6am to 5pm PST

Step 1: Enter Your Zip Code

Enter your zip code*, and we'll look up the the sun hours in your area.
Winter Sun Hours/Day
*Must enter zip code to gather data.

How many Sun Hours a day do you average in the darkest month?


We’ll start by using your winter low sun hours to size your PV array. Keep in mind your exact needs may vary depending on how your system will be used.

Step 2: Fill Out Load Calculator

Fill out the table below to estimate energy usage. We’ve included some common household appliances found in off-grid homes. Try to account for everything, keeping in mind that off-grid homes should use efficient appliances, and the major heating loads (water & air heating) are usually not electric.

Unbound Solar Load Calculator

Watts (Volts x Amps)
Hours On per Day
Watt Hours per Day
Show Appliance Consumption Table *
* Use these estimates to provide a
general watt value for your appliances.
Total Watts - (Peak Load)
Total Watt Hours per Day:
Kilowatt Hours Per Month:

Step 3: Calculate Off-Grid System Size

We'll estimate your off-grid system size based on the list of appliances and energy usage that you entered. Keep in mind that this is only an estimate, and there are many factors that can influence system sizing. Please contact us for help designing your project.

Click the "Calculate My System Size button" and we'll calculate your system size.

Minimum PV

System Size

This is a very general system size estimation. Other factors such as peak load, shade, location, available panel space, and seasonal use need to be taken into account.

For the most accurate and personalized off-grid system size calculation, call our solar experts at 1-800-472-1142.

We want to help you get the system that’s right for you.

Questions? Chat with us!

Wil has been a part of the solar industry for over 20 years; as an electrician, solar installer, support technician, and more. He's also been living off-grid since 1996. Wil and the rest of the Unbound Solar team are here to answer any questions you have about designing a system that will fit your needs.

Download Our Solar Battery Guide
A poorly designed system can ruin your batteries. Our Solar Battery Guide will help you size your battery bank properly and keep things running smoothly.
Get Free Guide
Can Opener150
Coffee Machine1000
Espresso Machine800
Freezer - Upright - 15 cu. ft.1240 Wh/Day**
Freezer - Chest - 15 cu. ft.1080 Wh/Day**
Fridge - 20 cu. ft. (AC)1411 Wh/Day**
Fridge -16 cu. ft. (AC)1200 Wh/Day**
Garbage Disposal450
Kettle - Electric1200
Oven - Electric1200
Toaster Oven1200
Stand Mixer300
Box Fan200
Ceiling Fan120
Central Air Conditioner - 24,000 BTU NA3800
Central Air Conditioner - 10,000 BTU NA3250
Furnace Fan Blower800
Space Heater NA1500
Tankless Water Heater - Electric1500
Water Heater - Electric4500
Window Air Conditioner 10,000 BTU NA900
Window Air Conditioner 12,000 BTU NA1200
Well Pump - 1/3 1HP750
Clothes Dryer - Electric3000
Clothes Dryer - Gas1800
Clothes Washer800
Living Room
Bluray Player15
Cable Box35
DVD Player15
TV - LCD150
TV - Plasma200
Satellite Dish25
Stereo Receiver450
Video Game Console150
CFL Bulb - 40 Watt Equivalent11
CFL Bulb - 60 Watt Equivalent18
CFL Bulb - 75 Watt Equivalent20
CFL Bulb - 100 Watt Equivalent30
Compact Fluorescent 20 Watt22
Compact Fluorescent 25 Watt28
Halogen - 40 Watt40
Incandescent 50 Watt50
Incandescent 100 Watt100
LED Bulb - 40 Watt Equivalent10
LED Bulb - 60 Watt Equivalent13
LED Bulb - 75 watt equivalent18
LED Bulb - 100 Watt Equivalent23
Desktop Computer (Standard)200
Desktop Computer (Gaming)500
LCD Monitor100
Smart Phone- Recharge6
Tablet- Recharge8
Band Saw - 14"1100
Belt Sander - 3"1000
Chain Saw - 12"1100
Circular Saw - 7-1/4"900
Circular Saw 8-1/4"1400
Disc Sander - 9"1200
Drill - 1/4"250
Drill - 1/2"750
Drill - 1"100
Hedge Trimmer450
Weed Eater500
Clock Radio7
Curling Iron150
Electric Shaver15
Electric Blanket200
Hair Dryer1500
Radiotelephone - Receive5
Radiotelephone - Transmit75
Sewing Machine100

Note: TVs, Computers, and other devices left plugged in but not turned on still draw power.

**To estimate the number of hours that a refrigerator actually operates at its maximum wattage, divide the total time the refrigerator is plugged in by three. Refrigerators, although turned "on" all the time, actually cycle on and off as needed to maintain interior temperatures.