To determine how many solar panels you need, gather six months to a year’s worth of electric bills. Ideally, you would also have a bigger sample to look at, and take into account peak hours when electricity is most expensive. For this purpose, some companies provide a twelve-month summation of electricity usage on every bill, while others may require only a single utility bill. In either case, you should be able to get a ballpark estimate of how many solar panels you need.
Your solar panel calculations assume optimum conditions, so you will need less than in a state with fewer sunny days. Generally, the more sunlight your home gets, the more energy your solar panels will convert. For example, Arizona, Utah, and Colorado receive more direct sunlight than states such as Colorado, New Mexico, and Nevada. But since long winters reduce solar panel efficiency, states outside of the Sun Belt may need more panels than states with a sunny climate.
The size of the solar panels will depend on your location. Some states in the northeast, for example, experience longer winters and shorter days during cooler months. Thus, a resident in these states will need more solar panels than someone in a sunnier climate. The efficiency of a solar panel will determine how much electricity it converts per square foot. A system with high efficiency means lower electricity bills. If you need more solar panels, check out the energy efficiency of the panels you choose.
Then, calculate your average electricity usage. For example, an average American house uses about 900 kWh per month, and receives five hours of peak sunlight per day. With that energy output, you would need six panels that produce the equivalent of that amount. This is a rough estimate of the solar panel needs for the average American household. And don’t forget that the more sunlight you receive, the more energy your panels will produce.
The power consumption of a home can be estimated by multiplying the amount of panels by the number of appliances. If you have three appliances, a 4kW system will use 13 solar panels. Similarly, if you have five appliances, then you need five panels. Once you have an idea of the power requirements of your home, you can choose to add solar panels if you increase your usage or add new appliances.
The cost of solar panels should be factored in to your overall energy budget. Since solar panels produce power for decades, you can expect to save money for the rest of your life. In addition to paying a set amount each month, you will also be credited for the energy you generate. That means you should factor in the cost of energy and inflation. And don’t forget to factor inflation. You can calculate your cost savings based on the current energy consumption and inflation and then add this figure into your calculations.
How many solar panels do I need depends on the type of home and the location. For example, a 1,200 sq. ft. home with two people will require fewer panels than a four-person home. However, if you live in a sunny location, you can get by with a small system. Remember, determining how many panels you need depends on your solar system’s efficiency. A standard residential solar panel is around 275W, so in general, a five-kW system will be sufficient.