If you’re thinking about installing a solar system for your home then this is almost certainly one of the first questions that comes to mind. If you’re going to invest in a solar system, well, you’ll probably want to know what it looks like and find out how many panels are involved! Below, we’ll take a look at some common factors used to determine the size of a system, and therefore the number of panels required.
Of course, it’s important to remember that there are a number of changing variables involved in calculating system size and there’s no one-size-fits-all approach. It’s not a simple equation where a house of x size with y inhabitants requires z number of panels. If you are considering going solar, the best option is always to contact a reputable solar panel installer directly and work with them to determine your own specific needs. However, If you want to start thinking about some potential factors determining system size before you make contact, please read on.
How Much Energy Am I Currently Using?
This is a solid first step toward understanding the scale of the solar system which would be required for your home. Thanks to the information provided by utilities companies in their billing, we can begin to understand the level of energy consumption in a given home. To determine your regular energy usage, it’s best to pull figures from a large sample of utility bills - ideally about a year or so of bills. This is particularly important in areas with highly variable climates - if you only assess bills from the bright summer months and neglect to figure in the dark winter then you won’t get an accurate assessment of your average energy usage.
The key measure we’re going to be dealing with here is the kilowatt hour (kWh), this is what energy companies generally use to measure consumption. So, if you use an appliance rated for 1kW (or a 1000 watts) for an hour, then you’ve used 1 kWh. Or, if you use two separate 500 watt appliances for an hour each, that’s 1 kWh as well, and so forth. Using the information provided on your utilities bill, you can determine your yearly kWh usage, and then break it down to daily/weekly/monthly averages from there. These figures are generally the first step to determining what system size would be required to cover 100% of your energy usage.
How Much Sunlight Does My House Get?
The location of your property in terms of climate, shading and sun exposure will also play a pivotal role in determining the system size required to cover your energy usage. The number of sun hours varies depending on location and refers not only to the daylight hours in your area, but also the hours of peak sun, where the sun is at its highest point. If you’re lucky enough to live in an area with an abundance of sun hours, you may require fewer panels. In an area with fewer sun hours, you may need a slightly larger system if you wish to offset 100% of your energy usage via solar.
Other Important Factors
Of course, calculating the output of a solar system, and by association the number of panels required, requires the consideration of multiple small, but important, factors. Things like the potential for shading and extreme temperatures, as well as the generally unlikely chance of voltage drops and other equipment inefficiencies must be accounted for in calculating system output.
Equipment is also a factor, the number of panels is often dependent on the kind of panels being used to put the solar array together. Different panels have variable performance, and there are a whole host of reasons for choosing one kind of panel over another. Everything from cost to location to simple aesthetic preference can come into play. On the subject of equipment, factoring battery storage, an increasingly popular addition, into the equation adds yet another variable.
Energy usage, climate factors, desired output, budgetary restraints - all of these factors and more are interdependent and will become constantly shifting pieces when determining the required number of solar panels. At the end of the day, it’s important to be aware that this is a very simplistic overview, and the best way to find out how many solar panels you need is to directly contact an installer.
By Shane Croghan