Prospective users of home solar power systems may find that they have different requirements in terms of the appropriate number of solar panels for their systems If you’re only looking to replace a portion of the power you currently get from the local utility, then any number will help. Calculating how many solar panels are needed to truly go off the grid only takes a few steps.

Step one is figuring out the amount of electricity you use in your home per day. To do this, first, gather up as many of your monthly electricity bills as you can. (Some utility companies now give you the option of referring to previous bills online.) Use these bills to see the number of kilowatt-hours (kWh) you use on a monthly basis. Your average daily usage can then be calculated by dividing this figure by 30.

Another key variable is insolation. The term “insolation” refers to the amount of usable sunlight the panels will receive in a given area. Solar panels require direct exposure to sunlight in order to generate electricity. Different solar panels require different levels of sunlight intensity in order to generate power. Sunlight exposure for a particular surface, of course, varies over the course of a year. These variations, of course, make a difference with regard to the performance of solar panels. The average exposure for a given area is indicated by its insolation value. Maps with insolation values can be found online. Once you’ve got the insolation value, divide your kWh usage figure from the previous step by the insolation value to find the amount of power you’ll need your solar power system to generate daily.

Power loss is the last variable to consider. Even with newer systems, there is still some power loss during conversion. The general rule of thumb in this respect is to act as though your loss figure is 25% (although you’re probably getting much less than that) just to be sure. Multiply the figure from the previous step by 1.25 to get the amount of power, including loss, that you’ll need. Now you can see how many kWh of energy you need, adjusted for insolation and efficiency.

If you divide this figure by the output in kilowatt hours of your solar panel of choice, you’ll see how many of these panels will be necessary in order to generate enough power to get you off the grid.

One of the earliest questions a homeowner faces when deciding on whether to install a home solar power system is, “How many solar panels do I need?” If you are curious to know the answer to this important question, you can check out, How Many Solar Panels Do I Need?

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