Use our Off-Grid Solar System Sizing Calculator to estimate how many solar panels you'll need, based on how much power you'll be using each day. All you need to do is enter your appliances along with how many, how long they're running, and how many watts. If you have appliances with an Energy Star sticker like fridges, you can put that number into the kWh/year column instead. Need a quick run through on using this calculator?

List Your Appliances

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.

Simply enter the Name and Quantity of each appliance, its Wattage rating, and how many Hours it will run each day, ignoring the last two columns. For things like a fridge, you can take the energy consumption number from the Energy Star Rating, and enter this in the final column, ignoring Watts, Hours, and Watt Hours. Need a quick run through?

Results will update automatically.

* View in landscape mode on mobile for best results.

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Appliance Quantity Watts Hours On Per Day Watt Hours Per Day kWh/year

Load Calculation Results

Total Daily Power Use Total Monthly Power Use Minimum PV Size Required
Watthours (Wh) Kilo Watthours (kWh) Watts

You'll need at least [[X]] solar panels to support that power usage.

We recommend you check out [[Y]]

Send Us a Copy of Your Results

If you'd like to talk through your solar power options, any other questions, or just want a second opinion, fill out your details, add any notes you have that might impact your results, and send us a copy of your results.

We'll be in touch as soon as we can to discuss the best option for you. Add your phone number if you'd like a call instead.

This is off-grid solar system sizing calculator gives a very general system size estimation. We've based this estimation on the assumption that you will get at least 3 peak sun hours for about 80% of the year (NZ average), so you may need more panels if you live somewhere with much less sun. 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 09 218 5533 or email us at

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