Solar Calculator: Estimate Your Home Solar Costs & Savings

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EcoWatch Solar Calculator

Use this solar calculator for a quick estimate of the savings you could see by installing solar panels. Our estimates use your location, shade level and electricity bill to provide an analysis of your solar potential.

We will not sell, trade or share your personal information without your explicit consent. Our results are not based on revenue or partnerships; they are intended purely to inform.


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Current shade
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The amount of shade that your roof gets.

Property type
How old is your roof?
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Roof age can impact the cost of solar panel installation.

How To Use the EcoWatch Solar Estimate Calculator

EcoWatch’s solar calculator is one of the best tools to help you determine your potential solar energy savings. This calculator not only estimates how much money you can save in your lifetime if you go solar, but it lays out a recommended size of your solar system, financing options and estimated payback period.

To take the first step towards your solar savings and connect with a preferred installer, follow these easy steps:

  1. Type in your address into the space above
  2. Fill out additional information about your property
  3. Click “Calculate My Solar Savings”
  4. Look at your results and compare solar quotes
solar panel cost calculator

Calculate Your Electric Bill Savings From Solar Power

After you turn to renewable energy, your monthly electricity bill will decrease for decades to come. In the best-case scenario, solar can help you offset your bills entirely.

Homeowners like to see this number extinguished, but there are a few factors that impact how much of a reduction you’ll see:

  • Your solar panel’s efficiency
  • Size of your solar array
  • Local utility rates
  • Your household energy consumption

You can easily contact your utility company to get a report of how much energy you consume each month. Once you have that number in kilowatt-hours (kWh), you can determine the cost of each kWh.

For the sake of this example, we are going to use the national average yearly energy consumption of 10,715 kWh1 and the average U.S. residential cost per kWh of 13.85 cents.2

Step 1: Let’s say that 10,715 kWh is how much electricity you use each year at the cost of 13.85 cents, or $0.1385. You would multiply these numbers together to get:

10,715 kWh (your annual energy consumption) x $0.1385 (cost per kWh) = $1,484 per year

Step 2: You spend about $1,484 each year on electricity without solar power. Now let’s say your solar panels are expected to generate 10,000 kW of electricity in one year. We would now subtract this expected amount of electricity from the amount you’re expected to consume:

10,715 kWh (your energy use) – 10,000 kWh (solar energy) = 715 kWh leftover

Step 3: Your system covers most of your energy consumption, but there is some leftover that you’ll need to pay for each month. Let’s determine how much by doing the same calculation we used to find out how much electricity you consume in a year:

715 kWh (leftover energy) X $0.1385 (cost per kWh) = $99 per year

Step 4: With the help of solar energy, you’ll only pay $99 per year on energy, or about $8.25 per month. This number may look different depending on the house and the time of year, but it does give us a good estimate overall. Your total savings would be:

$1,484 (total energy cost) – $99 (leftover for you to pay) = $1,385 in savings each year

This is a simplification, as our calculator also factors in rising utility rates, shade level on your home, the degradation rate of solar panels and more. However, these four steps reflect in simple terms how to approach the costs and savings associated with going solar.

How Many Solar Panels Do I Need?

Before you install your photovoltaic modules, you’ll want to know how many solar panels you’ll need to offset your utility bills. You will need to determine how much energy you use each month to accurately use this savings calculator.

A kilowatt-hour refers to energy consumption of 1,000 watts in one hour, and this is how your electricity company summarizes your monthly energy use. You will use this number to ultimately calculate the number of solar panels you need to cover your electric bill.

Solar Panel kWh Calculator

To calculate the number of panels you’ll need to cover your electric bill, follow the steps below.

Step 1: To calculate your daily energy use, simply divide your monthly energy use by the number of days in the month (i.e.30 days). We will use 30 kWh for daily consumption in our example.

Step 2: Determine the hours of sunlight you get each day. This number can range from less than three to more than six depending on your geological location and time of year, but we will use 5 hours to keep this simple.

solar power calculator photovoltaic potential map

Courtesy: World Bank Group

Step 3. Divide your daily kWh needed by the hours of sunlight your panels are expected to get:

30 kWh (your energy use) / 5 hours (sunlight) = 6 kW needed per hour

Step 4. Some energy is lost when your solar inverter converts your direct current (DC) into alternating current (AC), so you will need to divide your 6 kW by about 80%, or 0.8. You’ll then convert kilowatts to watts by multiplying by 1000:

6 kW / 0.8 = 7.5 kW DC

7.5 kW x 1,000 = 7,500 watts

Step 5. Divide the amount of watts required by your solar panel’s power rating. This rating is the amount of watts your panel is expected to produce. The number of watts can vary, but we’ll use a 250-watt panel for this example to get the number of panels you would need:

7,500W (your energy needs) / 250W (solar panel rating) = 25 solar panels

How Do I Calculate My Solar Payback Period?

Your payback period is the time it will take for your solar system to generate enough electricity to pay for itself. Every year, your solar panels will save you money on your monthly utility bill which will eventually completely repay your investment.

Just like with system costs, there are also many factors to consider when calculating your solar savings estimate, including:

  • Solar panel installation costs
  • Interest rates if you take out a solar loan
  • Applicable tax credits and solar rebates
  • Energy bill savings
  • Increases in utility rates

Energy bill savings will always be relative to the costs of electricity in your region, so areas that have higher utility costs tend to have shorter payback periods.

solar energy calculator payback period

To calculate your potential payback period, you simply divide the total cost of your solar system by your average yearly savings in electricity. So if you paid $30,000 for your solar panels and your average yearly electricity savings are $3,000, it will take just 10 years for your solar system to be paid off.

The warrantied lifetime of most solar panel systems is 25 years, so with a 10-year payback period, you can then enjoy 15 or more years of free, renewable energy. 

What Solar Financing Options Are Available To Me?

Like all home improvement options, there are several payment options available.These three most common options include:

  • Full Cash: Own the system outright by paying for it all at once.
  • Solar Loan: No or low upfront cost, but you own the system after you pay off the loan.
  • Solar Lease: Rent the solar system and purchase the electricity from the company that owns it.

If you pay cash upfront, you will ultimately pay the least for your solar system because you won’t have to pay interest or buy electricity from a solar leasing company. Not every homeowner has the means to pay in full, so loan and lease options are commonly used.

solar cost calculator projected lifetime savings

What Factors Affect The Price of Installing a Solar Power System?

Several factors affect the price of a solar power system, but the following are the most important when trying to calculate your solar estimate:

  1. Solar system size needs
  2. Types of solar panels and other equipment used
  3. Geographic location
  4. Available solar incentives
  5. Additional factors

1. Solar System Size Needs

Solar panel systems are priced per kilowatt, so the bigger your system, the more it’s going to cost upfront. However, a larger system is also going to produce more solar kilowatt-hours, which will offset more of your energy costs and could save you more money in the long run.

The only way to definitively know the number of solar panels you’ll need is to get a professional assessment. However, you can get a rough solar panel estimate by following these five steps:

  1. Calculate how much energy you use with data from your monthly electric bill
  2. Assess your roof space and the amount of sunlight your home receives
  3. Figure out the “specific yield” of solar panels in your area (the annual kWh of energy produced for each kilowatt of solar capacity installed)
  4. Check the wattage of the solar panels you intend to purchase
  5. Divide the wattage of your system by the wattage of those panels
  6. Check your data with that of a professional solar installer

To prepare for your professional assessment, use our solar calculator at the top of the page. The information you get from simply inputting your address can help you better understand your quotes.

2. Types of Solar Panels and Solar Equipment Used

Quality matters for solar panel cost and functionality. Panels with higher energy efficiency can deliver more watts per square foot, which means you need to purchase fewer of them to reach your electricity generation goal. These high-efficiency panels tend to be more expensive, but they will save you more money each month.

There are three main types of solar panels: monocrystalline, polycrystalline and thin-film. Monocrystalline panels are typically the most efficient solar panels, but they are followed closely by polycrystalline panels.

Thin-film solar panels, commonly known as flexible solar panels, live up to their name due to their sleek, thin design and low environmental impact. Their flexibility is a perk for many uses, but they are less efficient than traditional solar panels.

The type of solar panel you choose is only one component of your entire solar system. Other critical equipment you will need includes:

  • Solar inverter (to convert direct current (DC) to alternating current (AC))
  • Solar batteries/battery bank (to store excess energy)
  • Array DC disconnect (for when you need to cut power from your panels)
  • Mounting brackets, wiring and installation kits

Equipment needs can also vary, such as if you are deciding between a rooftop vs ground-mount panels or a grid-tie vs off-grid system. These costs are typically rolled into your solar estimate, but solar panel brands can vary on the total cost of your package.

3. Geographic Location

Because solar energy is directly dependent on your average sunny days, your geographic location is one of the most important factors to consider when you choose an energy system. The amount of direct sunlight you get not only impacts your monthly energy savings, but it can also impact your payback period. 

The more solar energy you produce, the larger your solar savings. For instance, a home in California is likely to need fewer solar panels than a home in New York — even if they have the same energy usage — because California has stronger solar potential and more days of full sunlight.

4. Available Solar Incentives

The upfront cost of a solar system can be expensive, which can be quite the deterrent for homeowners on a budget. To help the average homeowner overcome this barrier, both state and federal governments have established incentive programs to encourage homeowners to purchase solar panels. 

There is currently a 30% federal solar tax credit, called an investment tax credit (ITC), available for homeowners who install residential solar panels. This tax credit can be applied alongside other local rebates and other financial incentives to help offset the initial price tag.

Your solar system cost will also depend on the net metering policy of your local utility company. Most utilities vary in their buyback rates and feed-in tariffs, but policies can have a major impact on the overall value of your solar system and solar payback period. 

Your solar installer is your strongest ally and can help you find the right financing options, apply for solar incentives and navigate conversations with your local utility company. 

5. Additional Factors

There are many other factors that can cause the cost of solar panels to fluctuate, including:

  • The availability of solar panels in your area
  • Your current monthly electricity bill
  • The current cost of shipping
  • The number of providers competing for your business
  • Supply chain challenges
  • Local electricity rates
  • Your projected down payment
  • Loan, lease and repayment options
  • The climate in your area

How Do I Find the Right Solar Installer?

The key to the perfect solar system is the right installer. When you choose a top solar installer, you are guaranteed quality equipment, access to all available incentive programs and cost-saving warranties.

To find a preferred installer, fill out the solar panel calculator above. This not only shows your potential solar savings, but will connect you to the best solar installers in your area.

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Ecowatch

In the last decade alone, solar has experienced an average annual growth rate of 33%. There are now more than 121 gigawatts (GW) of solar capacity installed nationwide, enough to power 23.3 million homes.

The cost to install solar has dropped by more than 60% over the last decade, leading the industry to expand into new markets and deploy thousands of systems nationwide.

Continued growth in state community solar programs and improvements to state and regional interconnection processes are imperative to ensure solar access for all types of homeowners and businesses.