Quite a few people that are early on in their research into residential solar want to know how many solar panels to power a house.
Much like those asking about solar panel cost per square foot, it’s not exactly the right question to be asking. However, in a continuing mission to deliver some basic solar power knowledge, this question will be addressed and better ones will be revealed.
While asking “how many solar panels do I need?” might seem like a fair question, let’s go into detail why there are better questions to ask. The number of solar panels that homeowners need, or the size of their solar panel system, is based on their average yearly electricity usage. So the best starter question is “how much electricity do I use?” Since there is a wide range of electricity usage for any given homeowner, this number can vary widely.
To answer the question and give a typical range, the number of solar panels that are needed can vary from 10 – 30, on average. As of 2015, most solar panels have a wattage of at least 250, with some reaching 300. Being on the conservative side and using 250 watt solar panels, this would mean average solar panel system sizes can vary from 2,500 watts to 7,500 watts based on the 10-30 panel range previously mentioned. Some people will require systems considerably larger than 7.5 kilowatts, but that is not the norm.
The national average for residential electric usage is approximately 900 kilowatt-hours per month. A 20 panel solar panel system will yield as much as 700 kilowatt-hours per month. This 5 kilowatt system will only offset about 80% of the 900 kWhs used. This is typical as solar panel systems are not sized to completely offset total electric usage.
As you can see, asking how many solar panels to power a home is not quite the right question, but real close to it. Total electric usage throughout a year is what solar installers will need to know to determine system size and ultimately, the number of panels needed. It’a also good to note that most homes have enough roof space to accommodate the number of solar panels typically needed.
Feel free to leave a comment or ask a question for more information about solar system sizes.