How much solar do I need for my 2500 square foot home?

The amount of solar energy you will need to produce in order to power your home is not dependent on the size of your home. The amount of solar power you will need depends on four primary factors: what type of solar power system you'll need, grid-tie or off-grid, how much electricity you will use in your home each day, your location, and your budget.

First you will need to determine which type of solar electric system you will need. If you're in a location where the grid is available, you'll probably want to connect your system to the main power grid with a grid-tie system. If you want to either disconnect your home from the grid or your home is located beyond the reach of the power grid, an off-grid power system with a battery bank is what you'll need.
The second factor in calculating how much power your home will need is to determine the amount of electricity you use each day. If you're going grid-tie, then this information is readily available on your monthly electric bill. It will list the total amount of power (kWh) you used in the last billing cycle. Divide this by the number of days in your last billing cycle. This will tell you how much power you use each day (kWh). For off-grid systems, the calculation is a little more subjective as you'll need to estimate how much electricity you will need by factoring in your estimated daily usage of the items you want to use, such as a laptop and a lamp. Also, most people who need off-grid systems will need to use propane for heating and refridgeration appliances as well as for cooking. Reducing your electricity requirements off-grid will also help in determining how much solar you will need to install.
Third is something called solar insolation, which is the amount of solar energy that strikes the earth in a given location. If you live in the southern United States your solar insolation will be higher than if you live in the north, meaning your system will be smaller relative to your power needs in the south than it would be in the north. The climate in your location also plays an important role in calculating how much solar electricity you will need to generate. If you get more cloudy days as you would in Seattle, your solar power system will need to be sized larger than it would if you live in a sunny part of the country like Arizona.
Your budget is the fourth primary factor is the cost of your solar system. If money is not the issue and not a deciding factor, you'll probably want to produce 100% of your own power with solar and be truly energy independent. If you are on a budget, you may be better able to generate 50% of your energy needs. The percentage of your electricity consumption that you want your system to produce is very much dependent upon how much money you want to spend. Finally, the size and cost of your solar electric system is affected by the efficiency of the solar panels used. More efficient panels cost more money but may enable the installation of a smaller system.

So, as you can see, it's not as easy as saying "You'll need our 5kw grid-tie system." How much solar you will need depends on several factors. But, no worries! It's not as daunting an excercise as it sounds. Indeed, it's quite straightforward and easy to do. And just like most anything else, the bigger it is, the more it will cost. It might turn out that the solar energy system you need won't break the bank after all!

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