15 Things You Need To Know To Go Solar [Part 1]

There’s a lot to know about how solar works before you make the switch. Whether you’re interested in going solar for the dollar savings or you’re on a mission to help save the planet, having a strong understanding of solar basics will go a long way to assure you’re making an impactful investment. That’s why we have dedicated solar educators to answer your questions and guide you through the first strides of your solar journey. Although Mike and Davis (our solar educators) would love to talk solar with you all day, we know just how complex solar can be and that it’s hard to absorb all that information over the phone. So we’ve put together 15 things you need to understand before going solar to help you get started on your quest for whatever it is you’re out to save.

1. How does home solar work?

We could go in depth about silicon atoms and the P-N Junction, but we’ll hold back on scientific terms for this post. Here’s an overview of how solar panels power your home in five simple steps.

  • 1. Solar panels absorb sunlight and create direct current (DC) electricity.
  • 2. The electricity is passed through an inverter which converts the DC electricity to usable alternating current (AC) electricity for your home.
  • 3. Congratulations, your home is now powered by the sun! Any excess electricity generated by your solar system is sent back to the grid and recorded as a credit on your monthly utility bill or purchased by the utility at a rate they set (we’ll get to that later).
  • 4. At night or when the sun is not shining, you will either draw electricity from the utility's grid or from your battery system (if you choose to install one).
  • 5. You'll continue to rack up solar savings everyday for 30+ years while generating clean, renewable energy for your home and family.

Check out this graphic on how solar works from the Solar Energy Industries Association for more juicy technical details.

2. What are the parts of a solar system?

Module

Modules absorb energy from the sun to generate power. There are many options when it comes to choosing a module that can impact both appearance and performance. We’ll take a closer look at this in #3.

Inverter

Solar panels produce DC (direct current) electricity while your house runs on AC (alternating current) electricity. Your solar system will come equipped with an “inverter” which is the brain that will turn that DC into AC power to be usable in your home. The inverter also performs a lot of other important functions, like managing the power from the panels and making sure the right voltage is flowing into your home or back to the grid.

Racking

Solar racking, or mounting, is what holds the panels in place. On a roof mounted system, racking can be added to both new homes during the construction process or retroactively to existing homes. We use a rail-less racking system where we install clamps on the roof which clip into the panel’s frame. Ground mounted systems require a racking frame to be engineered and securely anchored into the ground.

Optimizer

Optimizers are installed on the back of each solar panel to mitigate the impact of shading on the system to maximize your solar production. They also help track performance so you can see how each panel is functioning which makes it easier to identify and troubleshoot any production issues. 

 

Optimizers operate similarly to micro-inverters, but they stand up much more reliably to North Carolina’s heat and humidity.  

Meter

Once your solar system is installed, your utility will come out to switch your old meter with a new fangled bi-directional meter. This meter spins forward when you are consuming energy from the grid and spins backwards when you are sending excess solar energy back to the grid. This allows you to be properly credited for the solar energy you send back to your utility.

3. Solar panel components and options

After being in the solar industry for nearly 20 years, we can tell you just how far solar panels have come in both efficiency and looks. There are three primary components of a solar panel: solar cells, backsheet, and frame. Each of these elements can come in different styles and be mixed and matched to achieve different looks at varying price points.

Solar Cells

There are two primary types of solar cells: polycrystalline (poly) and monocrystalline (mono). 

Polycrystalline (Poly) Cells

Poly cells are instantly recognizable by their space-age blue hue. Until a few years ago, poly panels dominated the market because they were significantly less expensive to produce. Today, however, mono panels have fallen in price and have taken a rise in popularity. Poly panels are now most prevalent in commercial and utility scale solar projects where their distinctive appearance is less of a consideration.

Monocrystalline (Mono) Cells

Mono cells are made from a single crystal which gives them their characteristic uniform black color. Not only are mono panels more sought after because of their sleek appearance, they are also more power dense and degrade less over time. The price of mono panels have dropped greatly over the past decade and they now make up the majority of our residential solar installations.

Frame

Much like a picture frame, a solar panel’s frame is what holds the sandwich of glass, silicon cells, and back sheet together. Solar panel frames are made of light-weight and durable aluminum and come in two colors: black and silver. Both styles perform the same, so it all comes down to aesthetic preference. Silver frames are typically paired with a poly cell and come in at a lower price. Black frames are definitely more popular for residential solar systems and pair nicely with poly or mono cells.

Back Sheet

Beneath the silicon cells in a solar panel is a layer called a back sheet. The primary function of the back sheet is to protect the components inside the panel, however, it does impact their appearance as well! Solar back sheets come in black or white. Most homeowners prefer a black back sheet with black cells and a black frame so their panels blend in better with their asphalt roofs.

4. Types of solar systems

Solar systems are either installed on a roof or on the ground. Which location is right for your home depends on a host of factors like shading, HOA restrictions, size of your yard, orientation of your home, your roof line, and more. 

Roof Mount

A roof mount system is just as it sounds — panels are attached to the roof with racking hardware. There are three basic factors that determine whether a roof will be good for solar.

What Makes a Good Roof For Solar?

  • Space: We need a reasonable amount of unshaded space to put the system on your roof. An average 4-6 kW system (16-24 panels) will need 200-400 square feet.
  • Orientation: Roof space also needs to be oriented well to capture the maximum sunlight over the course of the year. South-facing is best, but in some cases lower pitched east/west roof will work as well
  • Shading: Our design specialists conduct a shading analysis to make sure there aren’t too many shadows from trees. We use a tool called a Suneye that measures and calculates the available solar energy of the site by day, month, and year.

Ground Mount

For a ground mount installation, a racking system is engineered, constructed, and anchored into the ground. The electrical wiring runs in an underground trench to the house and the system is connected to the meter. The system operates the same as any solar system, following the five step process we outlined above. There are several pros and cons when considering a ground mount.

Pros

  • Customization: Can be positioned due south for maximum solar exposure
  • Space: Not limited by roof space allowing maximum production
  • Aesthetics: Great for customers concerned with home look, do not want it on their roof, are involved with a historical development/district that does not permit exterior changes, or have certain HOA restrictions

Cons

  • Material cost increase: More material is needed to mount and run the ground mount to the meter on the home, there are also additional costs for 'trenching'
  • Energy loss: As the electricity from the solar system runs to the home, there is a natural loss to the surroundings as it has farther to go

Solar Shingles

Solar shingles have been powering in and out of the headlines for the past few years after Tesla debuted their solar roof. Although still in limited production, the future of solar is definitely S3XY with options that camouflage the appearance of rooftop solar. We hate to rain on this solar party, but when compared to a traditional system, there are few pros among even more cons to this technology in its current form. 

Solar shingles aren’t a new concept, in fact we installed Dow’s version of solar tiles in 2014. Although we dream of a beautiful future where solar is fully integrated into the design and build of a home, and HOA’s have nothing to object to, our main concern is the savings potential of the solar shingles that are currently on the market. Right now, solar shingles are much less power dense than their cousin the PV module. On top of that, a full roof replacement is required when switching to a solar roof so there is also an increase in material and labor cost. This is why the payback on a solar roof is much longer than a traditional solar system. Check out our post “Tesla Solar Roof: To Wait Or Not To Wait” to learn more about the pros, cons, solar payback, and whether you should wait for the solar roof to hit NC.

Solar shingle meme

Custom Solar Structures

We love exploring creative options to integrate solar in the landscape and architecture of homes and businesses. Based upon your goals, custom solar structures can be as unique or as functional as you’d like. On the more practical end of the scale, awnings and parking lot shade shelters made from solar panels are a popular choice. We’ve designed and installed several of these systems including a beautiful porch roof constructed with frameless, glass-on-glass panels. Charging stations with solar umbrellas are an attractive alternative where form meets function. If you’re looking for wow factor, custom structures like the power flower we installed at Marbles Kids Museum in downtown Raleigh or the solar tree we did at Charlotte Discovery Place are both eye-catching and educational.

5. Alternative solar applications

There are many wonderful ways that solar can be used to power different parts of daily life. From solar powered weeding robots to powering vaccine refrigerators on the go, new solar technologies are always popping up. Two applications we are constantly asked about are solar water heaters and solar pool heating.

Tertill solar powered weeding device
Tertill by Franklin Robotics
Solar power keeping a refrigerator running on a camel's back to transport vaccines
NESTE Advanced Power Systems

Solar-Thermal Hot Water System

Solar thermal systems come in several varieties which all function slightly different. In general, a solar-thermal system heats water by transferring heat from the panels on the roof (known as the collector) to water that circulates through a series of pipes that run through the tank (known as a heat exchanger). This creates a circuit where cool water is pumped to the collector, heated by the power of the sun, then flows through the heat exchanger to the tank. As the water passes through the tank, it transmits its heat, cooling down to cycle through the process again. Here’s a great resource to learn more about how solar hot water panels work.

Many years ago we installed these systems for solar hot water. However, as PV technology has advanced and prices have fallen, we’ve found that it is actually more economically viable for our customers to invest in whole home solar instead of focusing on solar water heating. If you are still interested in a solar hot water system, we recommend getting in touch with the team at Solar Consultants.    

Solar Pool Heating

Solar pool heaters work in a similar fashion to solar hot water heaters by cycling cold pool water through solar collectors which heat the water before it is returned to the pool. We do not install solar pool heaters because of how specialized the technology is. Instead, we advocate that a similar outcome can be achieved by offsetting the energy consumption of an electric heat pump with a traditional pv system while also being able to power other aspects of your home with clean, renewable energy.

6. Utility interconnection types

Each electric utility has its own solar policy. Most of the time, solar homeowners will be generating more electricity than they can use when the sun is up, so knowing how the utility compensates for excess generation sent to the grid is crucial for determining the economic benefit of a project.

Net Metering

In North Carolina, net metering is the best way to hook up a residential solar system to the grid. In a true net metering scenario, all excess electricity you produce is either credited back to you on your account at the same rate as charged, or purchased from you at the same rate you pay. For example, if you are net metered, the power from your array will first flow into your home to power whatever is being used at that time. Any excess power will be sent back out to the utility for a 1:1 credit to be used later. If Duke is your utility provider, these credits will expire at the end of every May, so it is very important that the system is sized appropriately to the home’s energy usage.

Sell-Excess

Many co-op and municipal utilities require you to sell your solar energy back to them. Sell-excess interconnection is very similar to net metering except for one key difference — the excess electricity you generate is purchased at a very low wholesale rate instead of at the same premium you pay when you purchase power from the utility. This greatly impacts the financial benefit of going solar and extends the time it takes for the system to pay for itself.

Buy-All-Sell-All

Even less desirable than sell-excess, is buy-all-sell-all. This interconnection policy requires homes with solar to sell all of the electricity their system generates, typically at a low wholesale rate, while having to purchase all their power at the full consumer value. Under this model, there is a very low return on investment unless a battery system is involved. This is how all solar used to be installed in NC, but luckily that is not the case anymore.

 

7. Measuring solar production

One of the first terms that will be critical to understanding and talking about solar production is the term kilowatt hour or kWh. A kilowatt hour is the measure of energy consumption of 1,000 watts for 1 hour. If you use a 100-watt light bulb for ten hours, you would use one kilowatt-hour (kWh) of energy. To gauge your average energy needs, you can find your kWH consumption amount typically under “Usage” on your energy bill.

Energy Monitoring

For you to get the most out of your solar system, it’s important to know how much energy you are consuming in relation to how much power your system is producing. Energy monitoring also allows you to track and make sure your system is performing optimally. Most systems come with energy monitoring, however consumption monitoring is equally as important. Consumption habits often change when there is greater visibility and more awareness, just like how some people drive differently once they see their mpg on their dashboard. By using less energy and more efficiently, you will be able to maximize your investment and increase your savings.

What's Next?

Have more solar questions keeping you up at night? Check out Part 2 of the 15 things you need to know to go solar or reach out to one of our solar educators to have all your questions answered! 

15 Things You Need To Know To Go Solar [Part 2]

There’s a lot to know about how solar works before you make the switch. Here's Part 1 of the 15 things you need to understand before going solar.
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