By: Kelsey Meyers, Modernize
Whether you’re still considering going solar or you’re ready to take the first step, you probably want to know what system size you need and how that aspect will affect the cost. Unfortunately, it’s not easy for installers to give you an estimate based just on the size of your house or the dollar signs on your utility bill. But you can use your average monthly energy usage to get an idea of the number of panels you will need.
Determine Your Monthly Electrical Use
Look at your monthly energy bills for the last year and determine the average number of kWh, or kilowatts per hour. Divide this by 30 to get your daily kWh. Conservatively assuming that one standard solar cell produces 1 kWh per day, the number you just calculated is the number of panels you would need in order to completely cover your home’s energy needs.
In the meantime, reduce your home’s energy demands by buying more energy efficient appliances—that way, you may not have to buy as many solar panels as the calculator shows. Modernize has plenty of ideas for increasing the efficiency of your home before you install a solar system.
Find Out the Average Peak Sunlight Hours
But energy use isn’t the only factor. The amount of sunlight that your panels get also affects how many you will need to install. The more sunlight they receive, the more they are able to convert that radiant heat and light into energy for your home. If parts of your roof are shaded at certain times a day, you will need more panels to make up for that. As you monitor the quality and amount of sunlight that your roof gets, keep in mind that you’re going to need to install the panels on a south-facing roof for optimum efficiency. If trees or other buildings cast shade on your roof, or if you live in an area that doesn’t receive many hours of sunlight, you’re going to need to plan accordingly.
Decide How You Want to Use Your Solar System
While many prospective solar users dream of covering all of their energy costs, covering just a percentage is also an option. You may only decide to install enough solar panels to keep you out of the higher tiers of energy consumption, or you may just want to start off with just a few panels and build from there. You can customize your system to your budget—just be sure to avoid making compromises where it counts. For example, you wouldn’t want to buy a cheaper inverter to save money because this will only end up costing you, but you could start off with just one panel and slowly transition to using solar.