How Much Solar Power Do I Need To Power My Home?

solar panel efficiency

In the early days of solar energy discovery, energy was harnessed from the sun to power steam engines. Along the way, solar energy provided power to calculators, satellites, and other applications. Today, solar panels convert energy from the sun into electricity that can power your home.

Whether you want to go green with renewable energy or save on energy bills, solar power is the answer. Solar energy is clean, renewable, and abundant, making it the world’s clean energy source of the future. Find out how much solar power you need to power your home.

So How Many Solar Panels Do I Really Need?

Estimating the number of solar panels you need to power your home is based on the following:

  • Amount of electricity you use each month
  • Number of panels that fit on the roof of your house
  • The efficiency of specific solar panels
  • Size of the solar panels
  • Time of day for peak sunlight
  • Availability of metering with the electricity company

Because every home is unique, solar panels are not one-size-fits-all. The number of panels necessary depends on multiple factors.

How Much Do Solar Panels Cost?

Solar panels vary in cost like most other items. Standard solar panels cost an average of 65-75 cents per watt of electricity. Higher quality solar panels can cost between $1-2 per watt.

The federal government offers a tax credit to homeowners who convert to solar power to encourage solar energy use. Installation costs have lessened over the last ten years, making solar panel installation more affordable. The average price of solar panel equipment is approximately $10,000 with an additional installation charge. You can use our solar panel calculator calculator to get a better idea for solar panel pricing in your area.

Calculate Solar Panel Costs for Your Home

Many solar panel suppliers have online solar panel calculators, which can help you estimate the cost of panels for your home. These calculators will help you factor in the various aspects of going solar.

For starters, look at your past electricity bills to determine the usage for each month of the year. Some months will be higher than others as the climate influences how much electricity you use.

Next, find the kilowatt usage on the bills and use that number to calculate how much energy you use each day. To figure out daily usage, divide the kilowatt number by 30. That shows you how much electricity you used each day of the cycle.

You should also evaluate how much sunlight your roof gets in a day. Start keeping track when the sun hits the roof and stop when it no longer shines on the roof. This amount could be as much as eight hours of sun per day and as little as two hours.

You’ll also want to determine how much electricity you want to offset with solar power in one month. All of it?  Half of it? In general, one solar panel produces 1.24 kilowatts of power per day. Divide the amount of energy you need from solar panels by 1.24, and this will tell you how many panels you need to produce that much energy.

If math is not your strong point, use the solar panel calculator on the website to figure out the number of panels you will need to produce the amount of energy you desire.

For instance, the example of a three-bedroom, 2,000 soiree foot house below can help.

Determine Your Average Monthly Electricity Usage

Add all 12 months together and divide by 12 =  1,000 kWh per month

How Many Watts Do You Currently Use?

Looking at your current electricity bill will show you how much electricity you currently use. You will find this number under the kWh section of the bill.

Calculate Your Daily kWh Usage

To calculate your daily kilowatt usage, divide the current electricity watts by 30. This number tells you the average daily electricity used. For our example, let’s use 37 kWh per day.

Estimate the Amount of Sunlight Your Solar Panels Will Receive

The location of your home influences how much sunlight you get. For instance, a home in Maine does not get as much sunlight in the winter months, while homes in southern California get sunlight almost every day of the year.

Use peak sunlight hours to get an accurate estimate of the amount of sunlight your solar panels will receive. Peak sunlight is when the sun is shining directly and brightly enough to produce 1,000 kWh of energy per hour. For our purposes, let’s use 4.5 peak sunlight hours.

If you are unsure what your home’s peak sunlight hours are, contact an energy analysis expert to help you determine the peak sun energy production.

Factor in Your Potential Solar Power Usage

You must decide how much solar energy you need to replace the amount of electricity you want to stop using. On average, most solar panels produce between 245 and 500 watts of electricity per hour. When multiplied by the amount of electricity you no longer want to use, this can help you determine solar power usage.

Some homeowners want to start small by replacing 25% of their electricity use with solar power and increase as they grow accustomed to solar usage. Others want to replace all of their electricity use with solar energy from the start. A solar power expert can help you determine the amount of real solar power you need.

Our example continues: We will say we want to cover 80% of our electricity usage with solar energy

Our calculation so far: 37 kWh per day x 80% = 29.6 kWh of solar energy will replace the lost electricity.

Determine How Many Solar Panels You’ll Need

There are different levels of solar panels, with some being more efficient than others. While efficiency does matter, determining the number of solar panels depends on how much electricity you wish to replace with solar energy.

The number of solar panels you need is also dependent on how much wattage the panel produces. A solar panel with more wattage for energy use means that you will need fewer of them for your system.

If a solar panel produces 1.24kWh of solar energy per day, we would need 24 solar panels to supply the right amount of energy. 29.6 ÷ 1.24 = 24 panels

A skilled solar panel installer will help you estimate the number of panels you need to reach the solar power amount you want.

Limitations to System Design

While solar power is impressive and environmentally friendly, there are limitations to the system’s design.


One of determining factors for how many solar panels you can accommodate is the size of your roof. The available square footage that can hold solar panels influences how much solar energy you can have to replace electricity.


Most solar panels weigh approximately 40 lbs. The majority of standard roofs can handle the addition of solar panels; however, a solar panel professional would have to evaluate whether an individual roof can accommodate that much extra weight.


The cost of solar panels drops some each year. Because the federal government offers a tax rebate to homeowners who install solar panels, this is also a tremendous financial incentive. The current approximate cost of solar panels is around $2.75 per watt, or between $17,500-23,500.

What Other Equipment Is Needed for Solar Power?

Besides the solar panels, there is other equipment necessary to install and operate a solar-powered system. You will also need the essentials listed below.

An Inverter

Most homes use alternating current (AC) power, but solar panels need direct current (DC) power to convert the energy from the sun into usable electricity. There are several options for converting:

  • Microinverter: The microinverter attaches the solar panels to the electrical panel in your home. Each panel has a connection to the electricity that powers your home. This inverter type is what homeowners choose who want to know the wattage output of each solar panel. A primary advantage of this inverter is that if there is shade on one part of the roof but not on another, the sunny part still stores and converts energy.
  • String inverter: Similar to the microinverter, the string inverter is like a long string with connections to each solar panel. The string connects to the electrical box to supply electricity to the home. While this is the least expensive inverter type, a downside is that if one or more panels are not working, it slows the entire string and supplies less energy to your home.
  • Power optimizer: A power optimizer is a blend of the string inverter and microinverter. Less costly than the microinverter but more expensive than the string, a power optimizer is an excellent choice for a roof with sections of too much shade. The power optimizer is not an energy converter but funnels the solar power to a converter that connects to the electrical box in your home.

Solar Racking

It might surprise you that solar panels do not attach directly to the roof of your house. A rack holds the panels at an optimum angle, facing south at an angle between 30-50 degrees. This angle allows them to catch the most solar energy.

Two types of mounts are common. One is a fixed mount that does not move and is placed at the optimal angle and position. The other is a tracking mount that follows the sun and adjusts the angle of the panels for maximum solar energy.

Monitoring System

The two types of monitoring and performance evaluation systems are on-site monitoring and remote monitoring. The on-site system is installed as part of the solar panels, while the remote system tracks performance online.

Don’t Overbuild Upfront

It is tempting to want to install enough solar panels to cover 100% of your electricity use. This process is referred to as overbuilding. Installing more solar panels than you need to meet your electricity needs usually does not yield significant benefits.

First, some electricity companies will credit your bill if your energy production exceeds your usage. The thought is to use the credit down the line when your bill rises. In reality, what happens is that the credits stay on the bill for several months, and when you don’t use them by a specific time, they expire.

Second, many homeowners believe that the electricity company will pay them for excess electricity, but this is seldom the case. In the rare instance that they pay for the excess, it is at a much lower rate than what they charge you for energy.

Third, a more extensive solar panel system will cost more upfront. Plus, when you apply to add solar energy to your connection, the utility company will look back at past usage and might not approve a solar system that is much larger than your previous usage.

Plan for Backup Power

While some areas allow you to use electricity as a backup source of power, others do not. Many homeowners want to have a power backup for the nighttime or a series of cloudy days. In this circumstance, you can choose to have solar storage in the form of something like a battery.  A lead-acid solar battery or lithium-ion battery will supply backup power for a solar-powered home.

Some states offer a rebate or incentive for battery installation. This option has savings potential worth investigating. In addition, the federal government provides a refund for battery installation.

How Much Battery Do You Need?

When installing solar panels on your roof, the solar company will also install the batteries. These batteries cannot power everything in your home, but they can keep the lights on and power some appliances until the electricity returns.  The more battery backup power you select, the more expensive the solar panel system is.

The cost of solar energy continues to drop while the advantages continue to rise—it is genuinely the clean energy source of the future. When you are ready to see how a solar-powered lifestyle will change your energy needs, Solving Solar is the premier solar panel provider. We offer the highest quality solar panels with a clear track record of solar energy production.

Contact us today to discuss the many benefits of using solar panels to replace your electricity needs. Our online form makes it easy to get multiple no-obligation quotes for solar panel installation to help you save thousands of dollars in energy bills.