Buying solar panels: Homeowner’s guide

• There are three main types of solar panels: monocrystalline silicon, polycrystalline silicon, and thin-film.

• When sizing your solar panel system, consider the total wattage required to power your home, your daily energy consumption, and the solar irradiance in your area.

• The average price of a 5 kWh system in the United States is $17,823.

Solar power is one of the fastest-growing industries in the country, and it’s no surprise why: A solar panel system can help significantly reduce your electricity bills, bring you closer to energy independence, and lower your carbon footprint. As climate change brings higher temperatures and more demand for energy consumption, it’s a great idea to invest in sustainable ways to power your home.

In this guide, we’ll offer an overview of how to put together a solar panel system, compare some of the top panel brands, and take a look at how much a system may cost you. You’ll know the right questions to ask solar companies when checking out their products and what to look for in a solar installer. Solar isn’t best for everyone, though, so it’s worth getting all the information you need before making your final decision.

What to know about buying solar panels for your home

Deciding to go solar isn’t necessarily a simple process. The rewards can be great, but it’s essential to note that you’ll need to weigh several key decisions. These include the kinds of solar panels available, the size of the array you’ll need for your typical energy use, what brand of panels fits your needs and budget, and much more. In the following sections, we’ll hone in on each of these factors to help you make the best decisions for your home solar system.

Evaluating the best solar panels for home use

There are four main factors to consider when evaluating which solar panel is best for your home. These are:

• Wattage (Rated Power Output): Typical residential panels range from 300W to 450W per unit, so you’ll want to be sure the panels you choose fall within that output range.

• Efficiency Percentage: The efficiency percentage refers to the ratio of sunlight converted to electricity, and the higher the percentage, the more efficient the panel. 

• Temperature Coefficient: The temperature coefficient refers to how temperature affects a solar panel’s performance. It’s measured in percentages and degrees Celsius, and the lower the numbers, the better the panel. 

• Performance Degradation: Most solar panels experience a degradation of between 0.3% and 0.8% of their output annually. Most panels last around 25 to 30 years, so for the best return on your investment, you’ll want to select panels that have the lowest amount of performance degradation.

Comparing solar panel types for home energy needs

There are three main types of solar panels: monocrystalline silicon, polycrystalline silicon, and thin-film. The type of panel best suited for your home energy needs will depend on your personal preferences and the unique characteristics of your property.

Monocrystalline Silicon (Mono-Si)

Monocrystalline silicon panels are the most popular type of solar panels for rooftop installations. Because monosilicon solar cells are made from a single silicon crystal, electrons flow easily through the cell, resulting in high energy efficiency and a long lifespan. Monocrystalline panels' efficiency ratings typically range from 18% to 23%. 

Additionally, Mono-Si panels have a compact footprint, making them ideal for homes with limited roof space or premium residential systems that prioritize high energy output in the smallest space possible.

Polycrystalline Silicon (Poly-Si)

Polycrystalline silicon panels are less popular for residential installations, as they require more roof space and offer less output than monocrystalline silicon panels. Poly-Si panels contain multiple silicon cells, which constrain the movement of electrons and thus decrease energy efficiency. 

These panels’ efficiency ratings typically range from 15% to 18%. However, Poly-Si panels are less expensive than Mono-Si panels, making them ideal for budget-sensitive installations.

Thin-Film Panels (CdTe, CIGS, a-Si)

Thin-film panels have the lowest energy efficiency, with ratings ranging from 10% to 13%, but are the most affordable solar panels on the market as they’re much easier to manufacture and generate less waste. 

There are three types of thin-film panels: amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium selenide (CIGS). CdTe panels are the most commonly used thin-film panels, but all are popular due to their low weight and ease of adaptability to various types of surfaces. You’re most likely to see thin-film panels used in large-scale commercial or off-grid setups.

Sizing your system for DIY solar panels

When determining the solar panel size for your home's system, you’ll need to make a few calculations for daily electricity use, solar irradiance, and array size.

Daily Electricity Use

First, you’ll need to determine your daily energy usage, specifically in kilowatt hours (kWh). A kilowatt hour measures the amount of electricity an appliance uses in one hour. Your electric bill typically includes a summary section that displays the total kWh usage. Once you work out how much energy you use, you’ll be able to size the panel system you need more accurately.

Solar Irradiance

The next thing you’ll need to know when sizing a DIY solar panel system is the solar irradiance of your area. Solar irradiance measures the amount of energy from the Sun that reaches the Earth. To put it more simply, you’ll want to identify the peak sun hours—the amount of time that your panels will be in direct sunlight.

A peak sun hour is an hour in which the solar irradiance reaches an average of 1,000 watts per square meter. The amount of peak sun hours where you live, which will vary between an average of three and six, will dictate the number of solar panels you’ll need. The more peak sun hours your location receives, the more electricity your panels can generate, which could allow you to install a smaller system.

Array Size

To figure out the array size of your solar system, you’ll need to calculate the kWh needed to power your home from solar. To do so, divide your daily average kWh use by the average peak sun hours in your area, then multiply by 1.2. This equation accounts for efficiency losses and future energy needs.

Battery Storage Compatibility

Finally, to store that energy, consider using a battery in conjunction with your solar panel system. When deciding on the type of panels to purchase for your system, research the most compatible batteries and fit your budget. 

For example, lithium-based batteries are generally quite reliable, but they tend to be more expensive, which increases your upfront costs. Technicians are good resources here and may provide thorough recommendations.

Installation options for solar panels

Once you’ve compared solar panel types and figured out the size of your solar energy system, the next thing you’ll have to consider is the various installation options available, like mounting type, inverter type, and monitoring systems.

Mounting Type

There are two primary options for mounting your solar panels: on the ground near your home or on your roof. The tables below outline some of the advantages and disadvantages of both mounting methods.

Roof-mounted solar panels pros and cons

Ground-mounted solar panels pros and cons

Inverter Type

The inverter is a key component of a solar system. It takes the direct current electricity (DC) generated by a solar panel and converts it to alternating current electricity (AC), which powers your home. There are two types of inverters to choose from:

• String Inverters: These inverters are typically installed near your main service panel and serve as the central control of the system. They’re cost-effective and work best on unshaded roof systems.

• Microinverters: These are installed on the back of each panel, providing more granular optimization of your system. Microinverters are ideal for complex roofs or systems that experience shading.

Power optimizers are a hybrid between string inverters and microinverters, and are usually paired with a string inverter system. They are installed on the back of each solar panel and routed into a central string inverter, which converts the power into AC to power your home.

Monitoring Systems

A good monitoring system gives you real-time data about how your solar system is performing via mobile apps or web platforms. System manufacturers and installers typically offer monitoring systems, as do many third-party companies. 

Smart Meters and Grid Tie-in

If you’re tying into the local utility power grid, you’ll need a smart meter. It helps you monitor every watt sent back to the grid and allows for accurate net metering. If you’re off-grid, you can use a solar system without a smart meter.

Calculating the total cost when buying solar panels

According to our data, the average 5 kWh system in the US costs $17,823. Arizona has the lowest average cost for a system, at $13,958, while Hawaii has the highest, at $21,082. The average price per watt in the US is $3.56. The lowest price per watt in the country is $2.79, and the highest is $4.22.

The average payback period, which refers to the time it takes to recoup your initial investment, is 10 years. In multiple states, the average payback period is as low as seven years. New Mexico has the highest payback period at 16 years.

The savings provided by a solar panel system are significant, saving US households an average of $17,166 over 20 years. There are outliers, however. New Mexico has the lowest average 20-year savings, at $4,409, and Connecticut has the highest, at $32,080.

Note that these figures don’t include the federal residential solar tax credit, which is set to expire at the end of 2025. You could get a 30% tax credit if you install solar before then.

Choosing from the best solar panel brands

There are numerous solar brands to choose from, each with its pros and cons. The table below provides some basic facts about the top panel brands and key details to help you narrow your search.

Pay attention to performance and product warranties

When you settle on a particular solar brand, it’s important to note the performance and product warranties of the panels you choose. These are two distinct warranties that cover different aspects of the solar panel.

A performance warranty guarantees that a solar panel system will provide—and ideally, exceed—a baseline of power output over the panels’ lifespan. This warranty takes effect if the panel’s production falls below this baseline for a sustained period and will often involve the repair or replacement of panels as needed.

You may see a product warranty listed as an equipment or material warranty, which covers the failure of panels due to defects, equipment failure, or damage from environmental factors. These warranties typically last around 10 to 12 years and help cover the cost of replacing faulty panels due to issues such as corrosion, poor wiring, and premature wear.

Working with certified solar installers and local authorities

When choosing a solar installer, consider several key factors before making a decision, like credentials, company type, and customer reviews.

• Credentials: Ensure the installer holds an up-to-date North American Board of Certified Energy Practitioners (NABCEP) certification. Only work with licensed electricians who are bonded and insured.

• Company Type: Local installers often offer better service due to their regional experience, although they may be more expensive. National installers have pricing power, but less flexibility in scheduling, and may not have extensive experience installing solar panel systems in your area.

• Customer Reviews: Read the customer reviews for the system you choose and the installer you hire. Pay close attention to the documented power output that consumers report as compared to the promised output on a company’s website.

• Post-Install Support: A good installer will provide access to monitoring tools, repair timelines, and warranty servicing.

You’ll also need to work with your city and state governments when installing a solar system to make sure you’re abiding by the building codes. Talk to local authorities about the following:

• Building Permits: Learn about the permits required by your municipality and whether the permitting process necessitates a structural inspection. 

• Utility Approval: Contact your local energy company to learn about the interconnection agreement, which is a contract between you and the utility to operate your solar panel system in parallel with the utility’s power grid, and apply for net metering.

• HOA and Zoning Rules: If you live in a neighborhood with an HOA or strict zoning rules, consult the bylaws to check if there are any restrictions on panel system visibility or roof modifications.

• Fire Code and Setbacks: To comply with fire code requirements, you must leave access lanes between panels to allow fire services to access the roof.

How long does it take to buy and install panels?

The entire solar panel installation process typically takes two to six months from choosing a provider to activating your system. After selecting a company, you'll go through site assessment, system design, permitting, installation, inspection, and utility approval. Each step varies by location and provider, but most installs are completed within a few days, while approvals can take several weeks.

Understanding the long-term performance of home solar panels

Although going solar can require a significant initial monetary investment, the long-term benefits extend beyond lower energy bills. If you’re still on the fence about going solar, keep these four ideas in mind:

• Carbon Offset: Solar power helps significantly reduce your carbon footprint. The average system saves between three to four tons of CO₂ per year.

• Increased Home Value: Homes with solar systems installed often sell faster and at a higher price.

• Energy Independence: By eliminating the need to deal with constantly changing utility price structures and grid issues, solar panel systems offer greater control over energy sources and provide much more usage stability.

• Disaster Resilience: Pairing solar with batteries makes you more prepared in the event of natural disasters, providing self-contained backup power during outages.

Bottom line: buying solar panels for home energy

There’s a lot to consider when deciding to install a solar panel system for your home energy needs, but the benefits are hard to argue with. Once you determine the types of panels you want and the amount of energy you need to produce, you can fine-tune the specifics—such as the array size, mounting type, and preferred inverter type—to move toward greater energy independence.

FAQ about buying solar panels

Below are a few frequently asked questions about buying solar panels for home energy:

How many solar panels are needed to run a home?

Most homes in the US need between 10 and 17 panels.

How long do solar panels last?

Depending on the type of panel, most last around 25 to 30 years.

Do solar panels need maintenance?

Yes, solar panels will need to be cleaned and maintained every few months. A monitoring system can alert you to underperforming or damaged panels.

What is the 20% rule for solar panels?

Your solar panel system should provide 20% more energy than your home needs on average.