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Solar Power for the Home — The Basics

So, you want to want to become more energy efficient by installing a residential solar power system? Your want has immediately established you in a position to save on energy costs.  If you have decided to take a DIY approach to this project to save on the cost of installation, it is essential that you as the homeowner and new solar energy customer, be well informed. You must know what products you need to purchase for your solar system, and what these products do so you can understand your need for them. In addition, you must also know how to correctly install it while meeting all of your local building codes.

Determine Your Needs

Solar estimator/calculator.

The first step in installing any solar power system is calculating your current energy usage and need, as well as understanding the terminology behind energy, or power. Power is measured in watts. If you look at your most recent power bill, there is a Kilowatt per month total outlined. Remember, 1 watt is equal to 1,000 kilowatts of energy. A watt, itself, is a derived unit of power. It is the sum of voltage and current. Voltage is the rate at which electricity is drawn between two points; for example, voltage can be the rate that power is pulled from the physical wall-socket, or plug, in your wall to the appliance that is connected to that socket. Current is the quantity of the flow of this electric charge. Ways other than looking at your monthly electricity bill also exist to calculate your home energy consumption. Home energy calculators, available online, allow you to calculate wattage and wattage costs based on the wattage per hour cost of power in your area. You may also calculate wattage by looking at the tags on most of your home appliances, where wattage is usually outlined. Lists of average household appliance wattages are also available in lists online. To more accurately calculate your energy consumption sum at a certain time, you may purchase a home power meter for around $100. This meter plugs in to your appliance to get a precise wattage measurement. Once you have an estimate on your total home energy, you can better determine the power you will need for the pieces of your home solar system that need to be purchased.

With a firm grasp on what energy is and how much of it your home is consuming, you have to determine the amount of solar energy you will need to produce for your home to keep it running smoothly. An essential piece to this is knowing your average sun hours per day. Sun hours per day are the hours that full sun is available to you on an average day where you live. Full sun can be described as uninhibited, direct sunlight. These hours typically do not change, and a U.S. solar map can be used to assist you in determining this.

Check Local Laws and Regulations

Before you begin any installation of your well-thought-out home solar system, you should be aware of federal and state regulations. The federal government offers generous tax incentives to those who are planning on making their homes more energy efficient. These federal offices, however, are not the ones that put building regulations in place. You must become familiar with your state and local regulations and building codes to make sure your solar system meets certain safety standards. Extensive literature is available that makes building codes more understandable to the lay person, and also provides your information on how to avoid the most common problems and violations made when installing a solar power system. Your state energy office, local building code office, local solar power installer, or a renewable energy office near you will be able to provide area specific information regarding installation codes for your home solar power system. Further safety regulations require competent thinking on your part, such as realizing that there will be extra weight on your roof upon installation of the panels.

Purchase the Parts and Materials

If you have decided to do this yourself, then you must look in to the parts necessary to create your solar system. There are, generally, two ways to create a home solar system. One is to purchase all of the pieces separately, and the other is to purchase a grid-tie kit. A grid-tie kit contains all of the necessary pieces for your system, eliminating the need to purchase them separately. Depending on the specificity of your project, a grid-tie kit may be the easier route for a novice. If you choose to purchase everything separately for a more particular project, you can count on, at the very least, looking in to the necessity of the following: solar panels, mountings, combiner box, breaker, DC disconnect, inverter, batteries, and back-up generator. Let us look further in to what these pieces are and how they are combined to create solar power for your home.

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It all starts with the sun. The sun emits light, which is harnessed as power with a solar panel. A solar panel is made up of individual photovoltaic (PV) cells. A single cell is somewhere around 6 inches square. A solar panel installed residentially is usually between 30 and 40 PV cells large. These panels will be placed on your roof, or in another area that you deem fit to harness the sun power.  Read more about positioning solar panels.

Solar power, sunlight, is trapped in these panels and converted to DC power. DC power, or direct current, is raw energy. DC power is stored in solar panels, batteries, fuel cells, and other sources. Cables are run out from each solar panel and combined in to a single, large cable through a combiner box. The combiner box is really just a point where the wires from the solar panels are bundled in to a cable. A solar array breaker may be installed to the combined cable, protecting your wiring in case of a short. Next, the DC power goes through what is called a DC disconnect. A DC disconnect works as a breaker for the DC power that has just been harnessed in your solar array. It disconnects the power from the array in which it was created, so that it may be safely passed in to the next piece of your solar system, the inverter.

Converting the DC Electricity to AC Electricity

A pivotal point for power conversion is the inverter. Inverters convert electricity from DC current to AC current, or alternating current. As you know, solar panels create raw electricity, DC current. AC current is the electricity from which our appliances, therefore our homes, are able to run. An inverter is necessary to utilize the power that is created in your solar panels and stored in your batteries. Inverters are rated on the total number of watts they can continuously supply. If an inverter is rated at 7,000 watts, then 7,000 watts in your home can be supported indefinitely. To protect from a power surge, it is necessary to select an inverter that is at least 1.5 to 2 times the amount of total wattage of your simultaneously running appliances. Another interesting point about solar panel specific inverters is that they come standard with a Ground Fault Circuit Interrupter (GFCI) that prevents leakage of power and electrical shock.

After AC conversion via the inverter, unused energy is re-circulated, wired to output to your city’s power grid, or stored in batteries. Many utilities offer paybacks for your energy consumption, or purchase your unused power as an incentive to output it to the public grid. Or, if you so choose, you may store backup energy in batteries for later usage. Backup energy stored in batteries requires a charge controller, which prevents overcharging and backflow of energy to the solar cells during the night. Once DC power runs through the charge controller and in to the battery, it can be pulled from the battery when you need it, run through the inverter, and converted to AC power available to you within your home. A back-up generator may be an additional piece you choose to purchase for your system. This may be handy in case of adverse weather conditions (no sun) or absence of stored battery power.

Purchasing the aforementioned parts for your solar power system is very simple. A variety of solar panels exist from physical dealers, such as Mitsubishi Electric, Sunwize, Evergreen, and plenty of local green energy offices.   However to get the most bang for your buck,  doing your shopping online is smart and easy.  Buying from reputable online dealers (such as the partners featured on this website), makes solar system pieces and grid-tie kits easily accessible to the average homeowner. You may also find some parts such as mounting bits, DC disconnects, inverters, combiner boxes, and other electrical supplies at your local hardware store.

Now that you know the basics of what a home solar system entails, you are ready to look further into its creation.  If you do your research and always stay informed, there is no reason why you can’t enjoy the free power that is provided every day by the Sun!

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