How Many Panels will Your Home Need?

Determining the size of your solar energy system starts with a simple question: how many solar panels do I need? There is no one-size fits all solution. Usually you would want to produce enough energy to completely eliminate the electricity bill. The core is to determine what size solar system will produce enough power to meet your household consumption level.

At Home Bros we recommend you contact a professional solar contractor so that they can visit your home and provide a full assessment of what your needs are. If you work with Home Bros, our solar experts will handle the calculations for you. Consult professional solar installers for free home solar evaluation.



How many solar panels do I need to power my house?

To determine your home’s average energy requirements look at past utility bills. You can calculate how many solar panels you need by multiplying your household’s hourly energy requirement by the peak sunlight hours for your area and dividing that by a panel’s wattage. We also assumed that the average household consumes about 10,400 kWh per year and the panels we’re using are 250-watt solar panels.

How many watts do you currently use?

You probably consume more electricity during certain months of the year. Refer to your electricity bills for the past 12 months, and calculate your average usage (kWh) over that period. You can estimate daily kWh usage by dividing your monthly usage by 30. Your average daily energy usage is your target daily average for to calculate your solar needs. That’s the number of kilowatt-hours you need your solar system to produce if you want to cover 100% of your energy needs.

How many hours of sunlight can you expect in your area?

From the Pacific coast to the Atlantic, from cold northern states to the steamy south, the United States is filled with diverse climate conditions and varying peak sun hours. The Renewable Resource Data Center provides sunlight information by state and major cities.

Multiply your hourly usage by 1000 to convert your hourly power generation need to watts. Divide your average hourly wattage requirement by the number of daily peak sunlight hours for your area. This gives you the amount of energy your panels need to produce every hour.

What affects solar panel output efficiency?

Here’s where solar panel quality makes a difference. Not all solar panels are alike. Photovoltaic solar panels come in wattages ranging from about 150 watts to 370 watts per panel, depending on size, efficiency, and cell technology. Because of these wide variations in quality and efficiency, it’s difficult to make generalizations about which solar panels are right for you or how many you’ll need for your home. The more efficient the pnes are, the more wattage they can produce, and the fewer you will need on your roof to get the same energy output.

What is the effect of solar panel size?

Typical solar panels sizes today are about 65 inches by 39 inches, with some variation among manufacturers. If you have a small or unusual shaped roof, solar panel sizes and quantities are important things to consider. With a large usable roof area, perhaps you can sacrifice some efficiency and buy more larger panels at lower cost per panel, to get to your energy output. But if your roof surface is limited, or it’s partially shaded, using smaller high efficiency panels may be the best way to make the most possible power over the long term.

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