Man in blue uniform on roof installing solar panels on a sunny day.

How Do Solar Panels Work On A House?

Mar 21, 2022

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There is enough installed solar energy capacity in the United States to power nearly 22 million homes. Many homeowners and businesses are looking to the sun for energy because it is a clean and abundant source that can drastically decrease electricity bills.

In recent years, the efficiency of solar panels has increased dramatically, while the prices have plummeted. In addition, the federal government offers tax incentives, and some utility companies and state governments offer rebates that significantly reduce the total system cost. Now, solar systems are an economical source of renewable energy across much of the globe, causing it to skyrocket in popularity.

Let’s explore the basics of solar energy, including how it’s generated and common components in a solar energy system.

What Is Solar Energy?

Solar electricity uses the most abundant form of energy on Earth. In fact, the energy from just 1 year of sunshine far exceeds finite energy reserves, such as nuclear and fossil fuels. For this reason, solar energy has exceptional potential to curb climate change while meeting our energy needs.

There are different ways to use solar energy, including for electricity, space heating, and water heating. Solar photovoltaic (PV) panels are now the most popular and use light to produce electricity. By contrast, residential solar thermal panels generate heat which they transfer to water or other fluids. Solar thermal panels were more popular several decades ago, but now PV panels are more widespread because solar technology has advanced so much.

Whereas fossil fuel-fired power plants rely on burning a fuel source, such as coal or natural gas, solar PV panels do not. Unfortunately, extracting and burning fossil fuels is harmful to the environment and releases greenhouse gas emissions.

Although manufacturing solar panels and equipment does have an environmental impact, they do not rely on extracting additional resources to generate power. Thus, solar energy benefits the planet, a stable climate, and the pocketbook.

 

How Do Solar Panels Generate Electricity?

A solar panel generates electricity by allowing tiny particles of light called photons to knock electrons free from atoms. When photons strike the solar cells with enough energy, they can knock an electron from its bond. The electrons are then collected, generating an electric current.

Solar panels consist of many smaller units called PV cells, and numerous solar cells are linked together to make a solar panel. Typically, solar cells are made of silicon, a semiconductor, sandwiched between two conductive layers.

AC And DC Power

Electricity comes in two different forms: alternating current (AC) and direct current (DC) voltage. These terms describe the direction of the electrical current as it flows in a circuit. For example, with DC electricity, the current flows in one direction. By contrast, electrons switch directions for AC power, moving both forward and backward.

The vast majority of our homes use AC voltage to transmit electricity over longer distances because it is more effective. Therefore, if you plug into an electrical outlet, AC power flows out. Most televisions, washing machines, refrigerators, stoves, radios, electric heaters, dishwashers, and water heaters use AC electricity.

However, batteries and solar systems provide DC current. Thus, an inverter is needed for the battery or the solar array to power your AC appliances. The exception is off-grid solar panel system owners who occasionally use DC appliances to sidestep the need for a solar inverter. However, these homes are limited to a minimal selection of appliances and are uncommon.

 

What Are the Key Components Of A Residential Solar System?

Several critical components of a solar energy system are essential to integrate into a home’s electrical system.

Solar PV Panels

Solar modules convert the sun’s energy to electricity and are commonly mounted on roofs, the ground, and occasionally carports, trellises, or poles. Although solar panels are by far the most common, solar shingles or laminates serve a similar purpose but are often less efficient in generating electricity. However, some homeowners prefer the appearance of solar shingles because they can more easily blend into the roof.

There are many solar panel manufacturers, including Canadian Solar, Jinko Solar, Hanhwa, SunPower, LG Solar, Trina Solar, and Panasonic. These solar panels come with a product warranty of at least 10 years and a power performance guarantee, which ensures that the solar panels operate at a certain level of efficiency for up to 25 or 30 years. Typically, premium solar panels are more expensive but are more efficient and have more comprehensive warranties.

Inverters

Solar inverters are like the brains of the operation because they convert DC power from the solar panels to AC current for use throughout the home. The most popular brands include SMA, Enphase, Fronius, Solar Edge, Huawei, and ABB. However, warranties vary widely among manufacturers and range from a few years to 25 years. Some inverters offer an extended warranty for an additional fee.

There are two main kinds of inverters: string inverters and microinverters. A string inverter is a central inverter, thus a residential solar system typically has one or two. Therefore, a string can handle multiple solar panels.

The other option is microinverters, which are mounted on the backside of each solar panel. Thus, one microinverter is designated to each panel. If a solar system has 20 solar panels, it will also have 20 microinverters.

There are other setups that include a power optimizer that conditions electricity from each panel before sending it to a central inverter. This is a common option for systems where shading may hinder energy production.

Mounting Hardware

Mounting hardware holds solar panels in place. Although the hardware is often hidden out of sight, it is still critical, and it does impact the look of the solar system.

For example, it dictates whether the solar system has a low profile and is flush against the roof. With some designs, clamps are visible from the ground. However, some mounting systems have a skirt that helps conceal hardware or wiring, providing a clean appearance.

How the solar system is mounted impacts its ability to withstand wind and snow loads. For asphalt shingle roofs, the mounting system will commonly penetrate the roof. This is not the case for other types of roofs, such as metal or ceramic-tile roofs.

Energy Performance Monitoring

Today, most solar systems include solar monitoring systems so homeowners can view historical and real-time production data. Most of the time, monitoring systems use a platform from the inverter manufacturer. Sometimes, these systems provide panel-level data to determine how each solar panel is functioning.

Solar monitoring systems are an excellent way to detect maintenance issues right away before it has a large impact on long-term energy production. However, sometimes homeowners get concerned by performance data and think there is a maintenance issue when there isn’t one. For example, if a dormer shades part of the array in the afternoon, a drop in performance is not necessarily due to faulty equipment.

Solar Storage Batteries

Although many solar systems do not have batteries, they are becoming more popular due to advances in battery technology combined with falling prices. Unfortunately, adding a battery boosts the total system cost significantly, but also increases its capabilities. If you live in an area with an unreliable electrical grid and you really need power around the clock, a battery might be a worthwhile investment.

In areas with time-of-use rates, consumers pay different electricity rates depending on the time of day. Thus, homes with batteries can draw stored power when the electricity rates are highest and then recharge the battery either from the sun or the electrical grid when rates are lower. In such cases, batteries can result in cost savings.

Depending on the capacity of the battery, homeowners may still need to be diligent about their energy use during a power outage. Often, it is best to identify the most critical loads and provide power to those first.

 

What Are The Main Advantages And Disadvantages Of Solar Power?

Now that you understand the basics of how a solar system works, let’s explore the pros and cons.

Advantages Of Solar Panels

Considerable Return On Investment

One of the biggest advantages of solar energy is utility bill savings. Although it depends on the location, solar systems typically pay for themselves from the savings after about 8 – 10 years. But, the design life of a solar system is around 30 years. That means that homeowners often enjoy about two decades of free power.

Solar energy is also a very low-risk investment if using a reputable solar installer and manufacturers. Solar power systems are highly reliable, typically contain no moving parts, and require virtually no maintenance. Also, most homeowner insurance policies do cover solar panels, safeguarding you against issues including extreme weather, fire, or theft.

Environmentally Conscious

As the world looks for ways to slow climate change and improve air quality, solar energy is an excellent choice. Homeowners can go solar and also power electric vehicles (EVs) with the sun, reducing oil consumption and saving on gasoline.

Supports Local Businesses

In addition, solar power is good for the local economy. Typically, energy dollars for electricity and gasoline leave your community. By contrast, solar companies commonly hire local installers, creating high-quality jobs. Then, the solar panels produce power from sunlight that falls right on your property. It doesn’t get any more local than that.

Greater Grid Independence

Many homeowners also like having greater energy independence with homegrown electricity. Just think of how far the coal, natural gas, and other forms of energy must travel to supply energy to your home. Instead, you can produce electricity yourself!

Homes with batteries, in particular, can gain independence from the power grid while still keeping the lights on. This is especially helpful in areas with frequent or prolonged power outages, such as the emergency power safety shutoffs in California.

Potential Increase To Property Value

Another great benefit of solar energy is how it can increase the resale value of your property. Homes with solar panels are commonly cheaper to operate because they have lower energy bills. Therefore, solar properties can be more attractive to homebuyers, and they are often willing to pay a premium.

 

Disadvantages Of Solar Panels

Although there are many benefits to using solar panels, there are also some drawbacks.

High Upfront Cost

One of the biggest hurdles to more widespread solar energy development is the upfront investment. Typically, it costs thousands of dollars to install a solar system that can power an entire home.

Unfortunately, this is prohibitive to many households, especially low-income families. Thankfully, solar loans are becoming more prevalent and easier to obtain. However, there is still concern about equitable access to solar energy.

Manufacturing Panels Impacts The Environment

Although solar panels help protect the environment, they still have some impact. Many solar panels are manufactured overseas in Asia. Thus, the solar panels are transported long distances before they are installed, and this causes carbon emissions. Also, solar panels are difficult to recycle at the end of life. Although the infrastructure might improve in upcoming years, there is not a cohesive plan or national policy to keep solar panels out of landfills.

Solar Might Not Be A Good Fit For Some Locations

Also, solar energy isn’t ideal for all residences. Some homeowners associations prohibit homeowners from installing solar panels. Renters typically don’t want to invest in solar panels because they don’t own the property, and they are not eligible for the solar tax credits. In addition, some properties are shaded and don’t have good solar potential. As a result, community solar farms are growing in popularity in some states because they help sidestep some of these issues.

Solar energy production depends on available sunlight. Although most locations in the United States get ample sunshine, some areas are better suited than others. In highly snowy climates, we usually recommend installing solar panels at an angle so they can shed snow more easily.  Also, energy production varies seasonally, and sometimes on a year with more cloudy weather than is typical, solar energy fluctuates and occasionally is relatively low.

Net Metering Might Not Exist In Your State

Although most states have net metering laws which require utility companies to compensate consumers for the excess energy they feed to the power grid, a few states do not. Some of the states with no net metering laws or ones that do not adequately protect solar homeowners include Georgia, South Dakota, Tennessee, Oklahoma, and Hawaii. One way to sidestep this issue is to use solar batteries, but this has a significant upfront cost.

Understanding Solar Power Empowers Homeowners To Make The Best Decision

Solar shoppers need to be informed with accurate information to make the best decisions. Although solar energy is an excellent way for many homeowners to dramatically reduce their energy bills, it isn’t ideal for all homes. For example, if your property is heavily shaded, it may not be a good fit for installing solar panels.

At Rocket Solar, we are dedicated to providing accurate information to our potential customers to make informed decisions that are in line with their goals and values. To learn more about solar panels for your home, check out these other articles.

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