Installing A Solar Energy System Yourself: Knowing What to Buy

Tags: DIY Solar Installation, Installing Solar Panels, Solar Energy System, Home Solar Panels, Solar Modules, Residential Solar System, Solar Inverter, Disconnect, Power Meter, Home Breaker Box, Discount Solar Panels

Thinking about installing a solar energy system for your home, but you don't know where to start? If you are planning on installing a solar energy system yourself or hiring someone to install the system,  then you need to know what your most important choices are. Looking at all of the different equipment and options can be intimidating at first-even for an experienced DIY-er. This article will allow you to master some of the choices you will face as you are installing solar panels so that you can live long and prosper with your solar energy system. In this article, we will review the elements of a solar energy system and open the door for you to design your new project.

Once you have a general understanding of how the solar energy system functions, choosing the right parts will become much easier. This article will describe the parts of a standard grid tie (or on the grid) system. Staying connected to the power grid means you'll still receive power from the utility company when you need it, and in some states you may even be able to sell your excess power back to the utility. First, we'll discuss the components of the grid-tie system so that you know what to buy and what to plan for. Then, we'll review some of the options that are available with each of the parts. Finally, we'll discuss installation and financial assistance.

Layout of a grid-tie solar energy system
1. PV Modules
2. PV Array Disconnect
3. Grid Tie Inverter or Micro Inverters
4. AC Breaker Box (to house)
5. Power Meter


Major Component Parts of a Solar Energy System for Your Home.

In a grid tie system, electricity is first generated by one or several solar modules (also known as photovoltaic or PV solar panels). A shutoff switch known as a disconnect separates the panels from the rest of the system so that you'll be safe if you ever need to do any repairs. Next in line is the solar inverter, which will turn the direct current (DC) from the panels into alternating current (AC) for the household. From the inverter, power moves to your home breaker box and is distributed to the rest of the household. A power meter (probably different from the one you have now - capable of measuring power going into the grid or being pulled from the grid) at the end of the line will measure the amount of electricity that is either needed from, or being sold back to, the utility company. Now that we've outlined the distinct parts of a grid tie system, we'll discuss what to consider when planning your solar array.

You Will be Living with Your Solar Modules for Years: Choose Wisely

You first need to need to know a few basic things before you proceed to design you solar energy system. You need to know how much energy you want to produce, how many panels can fit on your roof, and what you can afford to buy. An array can be planned from any of these approaches. Knowing what you consume month-to-month is the best starting place - with this information, you can estimate what size array will produce this energy on a monthly basis, or how much energy can be produced in the space available, or how much energy you can produce with the money you have.diysolar2.jpg

Once you know what your target monthly output is in kilowatt hours (kWh), a little bit of Eighth grade math will let you calculate how big of an array you need. Once you understand this, you can focus on what kind of solar panels you want, where you'll put them, and how many you'll need. Look at your utility bills to figure out your daily average use - don't forget to account for seasonal changes. The average home in the U.S. uses about 900 kWh each month, but this average differs across the country.

You can divide this number by the hours of peak sun hours you receive each day to determine the size of your system. Did we lose you on peak sun hours? Peak sun hours are the number of hours per day anywhere on the planet where the solar insolation (or irradiance) equals 1000watts/square meters. No, you do not need to measure this yourself. You can find this information readily on the Internet for your precise location. You can find out how much sunlight you receive a day on the National Renewable Energy Laboratory website under the "US Solar Resource Map" for photovoltaics

Let's take an example. If you use a thousand watts daily, and you receive five hours of sunlight in a day, you'll need a 200 watt panel to completely cover your usage. In the Southwest, it could be over six hours, while in New England it could be just four hours. The process of comparing your power needs to sunlight availability, load calculation, is crucial to planning your setup.

Let's take another example using a little more complicated way of getting to how large you need to make your solar array. Take your monthly kWh number (900kWh) / 30 days / month = 30kWh/day. What size array makes 30kWh/day? Now you know that this depends on peak sun, and we will again use for this example five hours.  Depending on your location, 30kWh/day/ 5 peak sun hours = 6kW array, or 6,000 watts. For a 6,000 watt (same as 6 kilowatts) array, you would need 30 200-watt panels, or 25 240-watt panels. Most homes that are putting in solar energy can offset most of their electrical needs with an array that is between 4 - 7kW.

Now that you know how much power is needed, you can start designing your solar array. You can choose between two kinds of solar panels: traditional crystalline solar modules, and thin-film solar panels. Crystalline modules are the large solid panels that people usually associate with solar power. They are more expensive, and more efficient, than thin film. Thin film comes on a flexible roll of metal or plastic that can be applied to any flat surface, such as a metal roof. They are much simpler to install, but when roof surface area is an issue, high-efficiency crystalline panels may be a better choice.

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Racking Depends on Where you Install the Solar Energy System

With crystalline panels, you have three options for location: Mounting the panels on your roof, on the ground, or on a pivoting stand. You choose your racking depending on where you plan on mounting your solar energy system.

Most people think that a roof mount is the most convenient and aesthetically pleasing, but there are many reasons that people choose other options: if your roof is small, unstable, or in the shade; if you aren't able to face the panel towards the equator (facing south in the northern hemisphere and facing north in the southern hemisphere); if you like the simplicity of a ground mount; or if you have extra land. Pivoting stands are an attractive alternative because they are able to follow the sun throughout the day, so they can be far more efficient, but they're also more expensive. If you have enough open space, a ground mount may be better. With any of these mounting options, you should make sure that there are no local ordinances or homeowners association rules against them.

While most people want to focus on panels and inverters, it's important to remember that solar panel racks are critical. Besides the orientation and shading issues we discussed above, you also need to find out the wind category in your area as well as your soil conditions if you plan to install a ground mount system. Even with off-the-shelf parts, many permit offices will not give you a permit if the racking approach does not have a civil engineer's stamp of approval. Solar is still new to a lot of people, including engineers, but solar racking systems are in essence just giant erector sets and getting an engineer's approval of a proposed structure is often required. You should be able to hire an engineer for $500 or even less.

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Solar Inverters Are a Critical Component to your Solar Energy System

Now, having chosen your solar modules, you'll need to decide on a solar inverter. Again, the inverter changes direct current (DC) from the panel into alternating current (AC) that your appliances can use. There are several considerations here. First, you'll need to make sure to choose a grid tie inverter rather than an off-grid inverter. Second, you need an inverter that can handle what your panels generate, so make sure the wattage of the inverter is as strong as the wattage of your array. Third, you can consider solar micro inverters, smaller inverters that are connected to each panel instead of the entire system as a whole.

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Other Balance of System Components

After selecting panels and an inverter, the rest of the system (known as balance of system, or BOS) is simple to plan. You'll need to contact your local utility about the metering system - in most cases, they will give you the two-way meter (also known as a "net meter") for free. You can also consider a battery backup. For safety reasons, solar inverters will shut off current in a blackout, even if the array is making power, so that linesmen aren't zapped by errant solar systems while making repairs. If you install a backup battery bank, you can power critical loads independent of utility power. This requires specific wiring from the battery to the critical loads, but enables you to have power if the grid goes down. PV systems with battery backup are considerably more expensive.

Economic Incentives Will Lighten the Financial Burden

Now that your system is planned, you only need to figure out installation, solar financing for your solar power system, and other various legal issues. First, stop by Database of State Incentives for Renewables & Efficiency (DSIRE), an up-to-date database of energy efficiency incentives. The United States government will provide a 30% tax credit for eligible costs of your solar array, and you can find more grants, loans, and tax credits from your state or local government. DSIRE also has information on utilities that will buy electricity back from you. While you are reviewing this material, keep in mind that some incentive programs limits the benefits to those systems installed by an approved installer and are not available to those who install the system themselves, so be clear on the eligibility requirements of any programs you investigate. diysolar.jpg

There may be other incentive programs such as the Property Assessed Clean Energy Programs. At SolarTown, we will be launching a special solar financing program to allow you to defer payments on your purchase for up to one year. Please contact us for more information.

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Now all you need to do is plan your installation or you may choose to select a solar energy installer through Cooler Planet. If you do install the system yourself be sure to read our DIY solar installation tips!, Make sure to hire a licensed electrician for a safety inspection, or for just helping with wiring challenges Electricians are licensed and can pull permits with your local building office. More importantly, you can install your system all the way into your breaker box, but it will need inspection. Do not install a solar energy system without obtaining the permits required by your local government authority. Your local laws may require this, and other safety measures such as building permits, so be sure of these things before you begin. Once you're sure you're in the clear, you can start building!

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We hope that this guide has helped demystify some of the elements of a solar array and shown you what to consider to install a solar array. You've seen the layout of a system from the panels to the grid, and understand what parts you'll need to buy. You know how to make smart decisions about solar panels, and you know how to pick the right inverter. We also covered the importance of looking into legal matters and eligibility for government incentives. There are plenty of guides on this site about more specific considerations, and if you have any questions about your new solar array, please do not hesitate to contact us at SolarTown.