How to Calculate Your Solar Power Needs

By: Tom | October 31, 2023

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Solar Made Simple

Have you ever considered adding a home solar energy system but pumped the brakes due to information overload? If so, you are not alone! Solar energy can lower your electricity bills as well as reduce your home's carbon footprint. Yet, many of us are intimidated by the process because we are not experts on solar energy. Spoiler alert… you don’t have to be! Find out if a solar solution is right for you. Follow our simple guide and learn everything you need to know. From identifying your needs to finding a qualified installer, we’ve got you covered!

Estimate the Amount of Solar Panels Needed

Assessing your home's energy requirements is a crucial first step in this process. This information will allow you to confidently access your solar panel needs and review quotes from potential installers. Fortunately, this information is easily accessible by reviewing your electric bill. Your statement should clearly show your monthly energy usage in kilowatt hours (kWh). Monthly average will vary so take your previous year's total and divide by 365 to determine daily average kilowatt usage. Oftentimes, your previous year total power usage is already listed on your statement. Next, input this figure into the Daily Energy Usage (kWh) tab in our Solar Panel Calculator. Then select your state and choose the panel wattage you are considering. It's that easy!

Peak solar hours are based on state averages, so actual numbers may vary slightly depending on region. That said, these calculations should give you a reasonably accurate idea of your energy requirements and panel needs. During a consolation, professional installers will do a full analysis of your energy usage and make recommendations. Still, having a working knowledge of your needs better prepares you for this process.

Keeping it Real

Like automobile gas mileage, solar panel specifications are regularly overrated. In both cases, manufacturer estimates are made under ideal laboratory conditions. Rarely, if ever do these conditions perfectly match real-world operational environments.

Our estimates include a 75% derating factor. This accounts for various efficiency losses during normal everyday usage. Common issues like inverter efficiency and panel degradation over time contribute to energy loss. Including a derating factor creates a more realistic and accurate solar array estimate. Without it, the number of required panels would likely be underestimated. This can lead to a system that underperforms and doesn't meet your home's power requirements.

Using the 75% detracting factor ensures your system comfortably fulfills your needs.

Solar Panel Calculator

Enter your daily energy usage, select your state to get peak sun hours, and panel specifications to estimate your solar panel needs.

Daily Energy Usage (kWh):

Select Your State:

Single Panel Wattage (Watts):

System Derating Factor (0-1, e.g., 0.75 for 75% efficiency):

Important Steps Before You Install Solar Panels

Evaluating Your Roof's Suitability

So, the journey begins! The first step of any venture begins with surveying the road ahead. In this case, that means taking a close look at your home's roof to see if it is suitable for solar. If your roof is in need of repair or replacement, you'll want to address this prior to installing solar panels. Another consideration is the pitch of your roof. Ideally, a 15 and 40 degree slope will collect the most sun rays. The size and configuration of your roof will ultimately determine where and how many solar panels can be placed. And lastly, note excessive shade will greatly reduce your solar system's ability to produce power. Take some time to evaluate the best usage of your roof's surface.

Consider the Best Placement and Angle of Solar Panels

Which Side of Your Home Should Panels be Placed?

When considering where to put solar panels on a home, the south-facing side is usually the best choice. A south-facing roof gets the most direct sunlight for the longest amount of time. This gives solar panels the opportunity to generate the most electricity. However, a south-facing roof isn't the only factor.

What Angle is Best for Absorbing the Sun's Rays?

The angle, or "pitch," of your roof also plays a big role in how well solar panels work. If your roof is too flat, it won't catch as much direct sunlight. But, it may collect more dirt and debris, which can block the sun. If your roof is too steep, the sun's rays might bounce off rather than be absorbed. The ideal angle for solar panels depends on your location. Panels placed perpendicular to the sun's rays for the majority of the day yields the best results. A slope between 15 and 40 degrees generally offers optimal performance.

*Optimizing solar panels means finding a good balance of direction and angle placement. While a south-facing roof with a good pitch is ideal, placement does not have to be perfect to be effective. Professionals installers can analyze your home's unique features and make efficiency recommendations.

Assessing Your Goals & Expectations

Meeting goals and expectations largely depends on what motivates you to purchase solar in the first place. You may be a lifelong green enthusiast who wants to help maintain our global ecosystem. If so, we applaud you for that. If not, there is no shame in simply wanting to lower your electricity bills. Consider this a win, win for both sides. From a green perspective, our planet's deteriorating global environment is a real cause for concern. Solar energy provides a renewable, sustainable energy alternative that shrinks our carbon footprint. If doing your part to help stabilize our ecosystem's uncertain future is your primary agenda, choosing solar is a great first step. From a strictly economic standpoint, the rising cost of energy continues to put a burden on all Americans. Solar energy reduces our reliance on the grid. This leads to energy independence, long term savings and increased property value. Regardless of your motivation, going solar can help you achieve and possibly even exceed your goals and expectations.

Benefits of Purchasing a Solar Energy System

Why now is the best time to act

Large Tax Break for Solar Installation - Current federal tax credits allow home owners to claim a 30% tax credit on their income tax. But, In order to take full advantage of this tremendous savings, your solar installation must take place before January 1, 2033.. After this date, the federal tax credit will be reduced by 26%
Lower Installation Costs - The last decade has seen the market for solar energy mature; bringing prices down significantly. Industry growth has streamlined the permit process and created a much more competitive business environment. Due to this growth, consumers now have more options than ever when selecting a solar energy installer. Homeowner's can now shop and compare to find their best solar energy solution.
Attractive Finance Options - another great incentive is being able to space your payments out over a period of time. Many plans now allow for less cash upfront. The best part is that most monthly payments are less than your monthly electrify bill.
Long Term Energy Savings - Financing options allow for allows for an easier transition to solar by allowing your monthly energy savings to cover your installation cost. Solar panels have a typical life span of 25 years. Once your finance obligation is finished, the remaining life of your system will provide many years of free electricity.
Increase Your Homes Value - A recent Berkeley National Laboratory study determined that home solar energy systems are viewed as upgrades, bringing a premium price on the market. This conclusion is also shared by real-estate agencies and finance companies. Solar panels have a typical life span of 25 years. agencies and finance companies
Keep Power on When Grid Goes Down - Keep your family safe and warm when public utilities are down. It's great peace of mind to know that your home's lights will remain on and temperature will stay regulated when power outages occur.
Reduce Your Carbon Footprint - Going solar helps reduce greenhouse gas emissions and shrinks your carbon footprint. Feel good about doing your part to slow global warming!

How to Choose a Solar Energy Installer

the final leg of your journey begins...

Choosing the right installer is the most important step in the process. It's also the part that makes people feel the most anxious and intimidated. The good news is, you don't need to dive in head first. For a fast, confidential estimate, we recommend visiting energysage.com. EnergySage is a legitimate platform, backed by the U.S. Department of Energy. This site provides competitive quotes without sharing personal contact information. Estimates incorporate satellite imagery of roof characteristics like shade, orientation, tilt, and geography. Based on your location and monthly energy usage, they can offer a ball park estimate in minutes. They'll calculate projected total cost and potential energy savings as well. This is a great pressure free way to gauge how beneficial adding solar to your home can be. At this point, you'll have the option to receive more refined quotes from local installers. Before you do, it's important to verify their credentials.

Experience matters!

Look for a company with a proven track record. Check reviews and ask for references. Also, make sure the company you choose is industry certified. Refer to organizations such as NABCEP (North American Board of Certified Energy Practitioners) and SEI (Solar Energy International) for confirmation of a company's credentials. The solar installer will measure, cut and assemble support structures and make final installations of solar panels. They do so in accordance with your locality's building codes and standards. Before construction starts, permit requests will have to be submitted to the local building authority and electric utility company. Depending on who you select to complete your project, the permit process may be handled by the installer. The company you hire does not have to be a large national outfit to be worthy of your trust and consideration. But, they should have an established history of reliable, quality service.

*Now that you have a better understanding of what you need to know, it's time to take control of your future energy needs. You've got this!

Should You add a Backup Solar Battery?

Lastly, it's also a good idea to consider whether or not you need solar battery backup for your home. The majority of professional solar installs are connected to the grid. This allows you to potentially receive credit for excess power your home produces. It also means you can still access electricity sun periods are shorter or skies are overcast. The downside, during a power outage, your ability to draw energy from your is cut off. This is designed to protect the safety of those working to repair powerlines. Backup solar batteries store excess energy and keep you powered during an emergency. Read more about solar backup batteries...