How many solar panels do I need? is a common question asked by individuals and businesses interested in going solar. It is actually a good place to start as it establishes your baseline conditions and where you want to be in terms of going green and going solar. For going solar, it establishes how much of your current power you want to off-set by going solar which can range anywhere between 100% to 20% depending on how much sunlight or solar potential that is already available on your rooftop. Going green, you will be able to figure out how much of your carbon footprint that you can be able to reduce by installing solar panels on your rooftop.
Once you have figured out what are the goals for going solar, the following steps will guide you in knowing how many solar panels you need for your solar power system:
1. Figure out your daily electricity consumption in kilowatt-hours (kWh).
2. Calculate how much solar is already hitting your rooftop.
3. Establish the size of solar panels that you want to install on your rooftop.
4. Calculate how many solar panels you need to go solar.
1. Figure out your daily electricity consumption in kilowatt-hours (kWh)
You can determine this very quickly from your utility electricity bill, but since you want to get a good estimate, it is a good thing to contact your utility company to give you an average of your annual electricity usage, divide the figure you have by 12 to get your monthly electricity consumption and then divide your answer by 30 days to find out your daily electricity consumption in kWh. This is straight forward and can be figured out easily if you have access to your annual electricity usage.
However, if you for some reason you want to make a quick estimate you could probably use the average monthly electricity consumption as provided by US Energy Information Administration which estimates in 2016, the average annual electricity consumption for a U.S. residential utility customer was 10,766-kilowatt hours (kWh), an average of 897 kWh per month. Although this is just an estimate and your specific watts you consume will vary depending on the size of your home. For instance, how many bedrooms or bathrooms you have in your house will affect how many watts you need to power a 2 bed and 1 bath home etc. This will also affect how many solar panels you need to run a house.
2. Calculate how much solar is already hitting your rooftop
This is another interesting question you will need to know to determine how many solar panels you need for your house. There are various sources that you can access this information ranging from weather databases in your area, but today technology has simplified this process and you don’t have to dig many places to figure it out. Nowadays you can plug your address into simple online tools to determine how much solar that is hitting your rooftop. This information has been generated using LiDAR technology. Using LIDAR is quite accurate and will help to get good solar irradiation that can be highly relied on. You can also get this information from solar irradiation maps, but the figure you get will not be site-specific or for your particular house, but for the whole town or city.
EnergySage is one of those companies that has mapped the country using LIDAR technology to determine the site-specific solar potential for US homes. Using their energy system online tool, one can plug his/her address much faster and easier to figure out everything about going solar, including but not limited to: how much solar you can generate, your carbon footprint reduction, how many solar panels you need to locate as well as some of the best residential solar panels in the market that can be installed on your rooftop. Click here to get started and see how these tools are very interactive and user-friendly.
These online tools are proven and well tested. The tools were developed with the help of the government to help online users get a good experience when going solar and find the information they are looking for easily. Also, these tools are meant to help users make well-informed decisions, save time and money when shopping for solar while increasing productivity at the same time.
3. Establish the size of solar panels that you want to install on your rooftop
There are various solar panels out there of different sizes ranging from 500-watt solar panels, 300-watt solar panels, 200-watt solar panels to 1watt solar panels and so on. However, it is good to know what size of solar panels to pick depending on the size of your rooftop or anywhere that you want to place them to harvest solar energy. It is a fact that your solar panels will generate more power in summer than in winter because there is more solar irradiation in summer than in winter. A solar irradiation map will be a great source of data to help you determine your peak hours for solar irradiation. Places in California, Nevada, Arizona has some of the best solar potentials in the country ranging from about 5 to 6 peak hours ( 5 to 6 hours of sun per day at1 kW/m2).
For instance, in order to determine how much a 200-watt solar panel will generate in a day in places with solar insolation of 5 hrs, this will be equivalent to 200 multiplied by 5hrs which is equal to 1000Wh or 1kWh per day when using one 200 watts solar panel. So, how many solar panels do you need to go solar?
4. Calculate how many solar panels you need to go solar
Because we have already established the amount of energy consumed by your household on a daily basis and how much a 200W solar panel is able to produce when you have 5 hours of solar insolation, we can now calculate how many solar panels you need to go solar. To go solar 100% and assuming you consume the average electricity consumption of 897kWh per month, you have 897/30 which is equal to 30kWh and since one 200W solar panel produces 1kWh per day this is equal to about 30 (thirty) 200 W solar panels.
We can use this idea to calculate how many solar panels we need to go solar. However, this can be a little tedious to follow and research for solar irradiation. Although when you use simple online tools from EnergySage, it is possible to determine how many solar panels you need, including but not limited to your solar panel cost, ways of financing your solar panels and so on. For more specific or personalized solar data for your house, get started here with EnergySage.