Off grid solar power system size: How big does it need to be?
Many homeowners are happy paying utility companies every month to draw electricity from the power grid. However, more and more people are choosing to kiss expensive utility bills for unreliable service goodbye and produce their own electricity using solar power.
While it may seem daunting at first, it’s easier than you think to go off grid. You’d be surprised at how small a solar power system needs to be to meet all the needs of the average home, and there are many benefits to going off grid with solar power. Today’s solar technology is cheaper and more efficient than ever before. Affordable, long-lasting, highly efficient solar systems can help make your home or business self-sustaining for years.
Before you figure out the size of your off grid solar system, it's important to understand how solar energy works and how it will best fit your home. Read on and learn about off grid solar power system sizes, impacts, and financial implications to begin your energy upgrade. For any other off grid solar power questions, check out our FAQ blog here or take a deep dive with our comprehensive guide, Off grid solar power 101.
How is an off grid solar power system's size measured?
Off grid solar system size is based on the amount of energy that the solar system produces. The energy produced is primarily measured in watts (W) and kilowatts (kW), while kilowatt-hours (kWh) are used to measure energy consumption.
Off grid solar system sizes are measured in kW rather than physical dimensions to make it easier to determine suitable solar systems. When going off grid, the essential measurement is ensuring the system will efficiently produce the levels of power you need. The number of solar panels in the array doesn’t matter, it’s the amount of energy it produces that counts. Once you've determined how many kW you need in your solar system, finding a kit that matches the necessary output and fits where you want to install it should be relatively easy.
How big is an off grid solar power system?
It’s hard to give even an approximate estimate on how many kW an off grid system is because of how many things impact this. Energy needs and location are the prime factors, and it’s all based on the individual system. Given the national average of 30 kWh daily energy consumption and 4.5 hours of peak sunlight, the average solar system size would be around 6 or 7 kW, but you won’t know how big your system needs to be until you do the calculations.
If you’re talking physical dimensions, specific solar panels can vary based on the panel's output and the manufacturer's individual specs. For example, our 6,000W (6kW) Off Grid Solar Kit has six 390W panels that each measure about 69 by 41 inches meaning you need an outdoor space about 18’ by 7’ or 12’ by 10’ to install them. The indoor components are small enough to fit in the area around your electrical panel. The battery bank will take up the most space, but it’s very uncommon to have a problem finding room for it.
What impacts the size of an off grid solar system?
An off grid solar power system's size is determined by the power needs of your property. Consider the appliances you use, how often they're used, and how much sunlight the solar panels will receive.
A dependable off grid solar system is responsible for powering your property day and night, so the amount of energy the panels absorb during the few hours each day when they receive maximum sunlight must be enough to last 24+ hours. The size of your battery bank must be able to store at least enough energy to get you through the rest of the day and night. But to be on the safe side, you should have enough battery capacity to keep you going for several days.
Start by tracking how much power your household or property regularly uses based on the appliances you need to operate. According to the US Department of Energy, an appliance's daily kWh consumption can be determined by multiplying its wattage by the number of hours it's used per day and dividing that by 1,000.
Complete this equation for every appliance in your house to estimate your home's daily kWh consumption. Investing in a whole-house energy monitoring system can also help you determine a more specific kWh estimation.
Deciphering the exact amount of energy your household uses each year can be difficult, and results may be unreliable for homeowners that don’t know what they’re looking for. Get a quote from a professional to make sure you know exactly how much solar power you need before going off grid.
Next, consider where you live and the amount of sunlight your solar system will receive. For example, Washington receives up to 16 hours of daylight on its longest days, while Florida gets just under 14 hours. However, solar systems in "The Sunshine State" of Florida are more likely to receive direct sunlight throughout the day than those in Washington, which has one of the cloudiest coastlines in the country.
However, when it comes to solar power it’s not about how many hours of sunlight your panel array receives in a day, but rather the intensity. Panels absorb the most energy when solar irradiance reaches 1,000 or more watts per square meter, usually during peak sunlight hours. Many online resources can help you identify peak sunlight hours for your region.
Other factors to consider about your location include:
- the number of trees around your property
- where on your property the system will be installed
- changing weather conditions
- planned upgrades that may impact your property's energy usage
What if I need more?
Though standard solar kits may produce the kWh you need when you install them, you may find yourself needing more power in the future as your needs change. As a solution, most kits include extra inputs for installing additional solar panels and energy storage. Supplementary solar panels increase the kW your solar system absorbs, usually by 100W to 400W per panel.
Additional energy storage options, such as Deep Cycle Batteries, keep your property covered on cloudy days and days, such as holidays, when you use more power than usual. Reliable batteries can be fairly expensive, so many homeowners start with smaller batteries and upgrade as their power needs increase. We've got a great list of the best off grid solar batteries to help make your choice.
How long will it take to pay off the cost with utility savings?
We'll be honest, setting up an off grid solar power system isn't cheap, but it's probably a lot more affordable than you think, especially if you go with an off grid solar kit. But it's so worth it because an off grid solar power system is a long-term investment for your property that eliminates your monthly electricity bill. It will increase your property’s value, but it will take some time to recoup the initial investment. It’s common for people to take a loan to pay for their system, using the savings on monthly electricity bills to pay the loan off.
To identify how much you'll save on energy, first, calculate your average kWh usage. Then, multiply this number by the average cost of energy usage per kWh in your state. For example, if you use 11,160 kWh per year and live in a state where the average energy cost is $0.16 per kWh, you will save about $1,700 annually.
Assuming the solar system in the example above costs $12,000 to install, it would take just over seven years to pay off the investment in full. However, this doesn’t take into account system upgrades, such as replacement batteries, or increased utility rates you would have paid if you’d stayed on the grid.
How long will my solar system last?
A dependable solar panel should last about 25 to 30 years. For added protection, our solar panels come with 25-year warranties.
Similarly, solar system batteries and storage last about 10 to 20 years and come with 10-year warranties.
Beyond the panels and batteries, almost everything else in our solar panel kits should last indefinitely if left undamaged. However, as solar technology continues to evolve, it's difficult to predict what solar panels will look like in a decade or two. A 2023 model solar panel may not be as efficient as a 2033 model — but that's no reason to wait to invest in renewable energy. By waiting to invest, you could be missing out on years worth of efficient utility savings. Modern solar energy is worth investing in, both in quality and cost.
Invest in off grid solar energy
Investing in an off grid solar power system is an ideal economic decision for many households, businesses, and property owners. By upgrading your energy and disconnecting from the unreliable and expensive power grid, you can make yourself more self-sufficient, save money, and help the planet by contributing to nonrenewable energy.
Contact a professional from our team today to receive a quote and determine the right solar kit for you. Check out our comprehensive off grid solar power guide to learn more and become an expert in off grid solar power.