# How to Determine the Right Sized Solar Panel System for Your Home

## Nicki Zvik, Founder of Green Solar Technologies, comments on how to determine the desired size of a solar energy system.

Nicki Zvik, Founder of Green Solar Technologies

Making the switch to solar can be a big step in anybody’s life, and an even bigger investment at that. So it is important to know just what you’re getting yourself into when deciding to go solar by asking yourself things like:

“How much will it cost?”
“How much will I save?”
“When will I start seeing ROI?”

And so on. But to answer these questions, one must first determine the size of the solar panel system to be installed.

Nicki Zvik, Founder of Green Solar Technologies, explains, “The size of the desired solar system really depends on a variety of factors. Things like budget, home size, rooftop space and even location can have an impact on the size of a solar panel system. But if we are talking about simple math to determine what size solar panel system a home will need to completely replace the energy required from the utility companies, then it becomes much easier to figure out.”

Though lengthy, the math is quite simple.

Solar Power Authority gives a great step by step method to determining how big a solar system will need to be. The steps go as follows:

1. Collect your electricity bills for the past year so you can calculate your average monthly electricity usage. Calculating an average is essential because electricity use peaks in the hottest months due to the high air conditioning demand.

2. Add up the kWhs for all 12 months and divide that number by 12 to determine your average monthly energy consumption.

3. Divide the monthly figure by 30 to determine your daily kWh usage.

Determine Insolation

1. Locate a solar insolation table online (see Resources) to determine the insolation, the average number of hours per day that the sun produces peak sunlight (or an accumulation of all sunlight equivalent to that amount of peak sunlight), for your area.

2. Find the nearest city to you on the table and write down the average daily figure. To determine specific insolation data for individual days of the year, use NASA’s Atmosphere-Ocean Model...

Calculate Energy Needs

1. Plug the figure from Section 1, Step 3 “Daily kWh” into the following calculation. Use the average insolation value from Section 2, Step 2 for the “# hours” to determine how many kW you need your solar system to generate per day:Daily kWh / # hours = # kW
e.g. 12 / 4 = 3

2. Plug the answer from the previous step into the following calculation, which accounts for standard energy losses of solar PV systems:# kW x 1.3 (increase size of PV system by 30%) = # kW (actual size of PV system you need)
e.g. 3 x 1.3 = 3.9 In this example, you would need a 3.9 kW solar PV system to satisfy your home’s energy needs.

Total Number of Solar Panels

To calculate the size of your solar photovoltaic system, take your daily kWh energy requirement and divide by your peak sun-hours to get the kW output you need. Then divide the kW output by your panel’s efficiency to get the total number of solar panels for your system.

After you know the number of panels you need, the next step is to determine if you can fit them all on your roof, and if you have the right kind of roof to mount panels on.

Selecting a Solar Panel System

1. Measure how much space you have to mount your solar panels.
2. Decide on a budget for your system.
3. Find a system that satisfies your power requirements, but still fits within your space restrictions. This will determine if you need a roof-mounted or ground-mounted system, and if you’re eligible for a solar roof shingle system.”

“With any investment, there is some work involved, but lucky for Green Solar Technologies customers, they’re not alone,” says Zvik. “Our solar experts are here to guide our customers through every step including determining the size of their desired system. And once the project is complete, our customers can rest assured that we will be here for them whenever they need us.”

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Jennifer Wesley
@greensoltech