With the energy pricing skyrocketing and the terrifying utility bills each month, solar panels seem to be a reasonable choice for many households. It produces greener energy and plummets the dependency on the power supplied by the electrical grid. The residential solar panel is also an effective way to get rid of the burden of rising energy prices. But, choosing the right one is not a child’s play. You have to consider lots of factors to make that decision.
How Does a Solar System Work?
Certain materials can produce electricity from light, which is known as the photovoltaic effect. Solar panels are made of those components that can convert the energy from sunlight into DC (direct current). Every system has an inverter unit that transforms that DC into AC (alternating current) for the electrical circuit of a household.
What does it do with the excess energy? Well, there are two ways: storing into a battery storage system for later use or feeding back to the electricity grid. The second option is financially beneficial given that there is an agreed feed-in tariff.
A solar panel works best when it gets the direct sunlight. You should install it north-facing and at an angle that is free from all types of obstructions, including trees, adjacent buildings, or shades. Remember that the residential solar panel is not a viable option if you live in an area where the weather remains mostly cloudy or snowy.
Residential Solar Panel – The Types
The solar systems available on the market have some basic differences between them. Having the right information is necessary to help you figure out the right choice, based on your energy needs.
Isolated from the traditional electricity grid, it uses batteries to store power for reserving the excess production. Most units use a generator as a failsafe when the system cannot produce the required electricity or if the batteries are discharged. Generators come handy in bad weather conditions when sunlight is scarce and the panels cannot meet excessive demands.
The off-grid systems are suitable for households that need a minimal amount of power or for remote places where solar panels are more cost-effective than extending lines from a utility grid. It’s also useful as a part of the hybrid power-generating network that also uses wind electric and hydroelectric systems.
Grid-Connected PV System
As the name suggests, the photovoltaic power system has a connection to the power grid. A whole system features solar panels, a power conditioning unit, one or multiple inverters, and equipment for grid connection.
Unlike a stand-alone unit, the grid-connected power system does not have a built-in battery storage, although, some high-end, expensive models may have this option. There is a seamless switch between the solar system and the main grid. You can sell the produced excess power to the utility and draw power from the grid when the production is inadequate. It can be done through an inexpensive process called Net Metering that ensures power provider pays the retail price for the electricity you feed back into the grid.
The PV systems are suitable for small households, commercial facilities, and large-scale solar power stations.
Grid-Connected System with Battery Back-Up
It is similar to the PV system except for the additional battery backup. The system is the best option you can ask for, considering the balance it strikes between the electricity production and demand. With a unit installed on your rooftop, you won’t ever have to worry about power outages. Additional electricity will be stored in the battery for later use, while the power grid is there to supply energy if there is any shortage.
The continuous charging and recharging of the backup batteries is a downside though, since it decreases the overall efficiency of the system. Also, it is more expensive due to the complicated design and installation.
Types of Solar Cells
Not all solar modules use the same solar cells. There are three categories depending on their characteristics and performance:
- Cells using monocrystalline silicon are highly efficient with a good heat-resistant rating. They also leave a very small footprint.
- The polycrystalline silicon cells are currently the crowd favorite for residential solar modules. They are better than monocrystalline cells when it comes to productivity and heat tolerance.
- Amorphous silicon cells are the least efficient of all the varieties. The low-end and inexpensive solar modules use these thin-film cells.
How to Choose the Right Residential Solar Panel?
Not all solar panels share the same quality or yield the same performance. Low-end, cheap panels won’t produce power at the same efficiency rate as the high-end units. You also have to consider a variety of other factors other than the price tag to make a purchase decision.
All the products are tested for efficiency, power output, and operating temperature coefficients in standard conditions. Comparing various models for these variables will help you find the right choice.
It refers to the power output measured in DC under ideal conditions. Most of the panels are rated between 200 and 400 watts. A solar module rated 200 watts will not produce exactly that amount of current since the rating is given for the ideal condition. A number of variables, including weather conditions, sun exposure, temperature, tree cover, and more, influence that rating in a real-world situation. So, if your house needs 200 watts of electricity per day, buy a unit rated for 250 watts.
There is also a power tolerance rating that could be positive or negative. A positive sign for a 200-watt panel means that it will produce more than 200 watts in standard testing conditions and a negative sign indicates the opposite.
This variable indicates the rate of converting light into electrical energy. You will know how many kWh (kilowatt-hours) of electricity your module will yield for each watt on the nameplate rating.
The mid-range products have the efficiency rating at or slightly more than 15%, while it could reach 20% for high-end models. The conversion rate is poor because almost 80% of the output is lost as dissipated heat.
A solar module loses productivity in extreme heat. The ideal temperature is 77°F, and every 4-degree increase makes the panel losing 1% of its efficiency. You should choose units with a low-temperature coefficiency if you are living in a hot climate.
It stands for potential-induced degradation and refers to the loss of electricity. Certain climatic conditions trigger the stray currents and cause this substantial power loss. A high-quality residential solar panel will have little or no PID.
It denotes light-induced degradation that occurs within the first few months after installing a new solar module, decreasing the amount of the total power output. The condition stabilizes after a certain period. However, a good unit should have little or no LID.
The longevity of a residential solar panel depends on the use of high-quality materials and strict quality control during the manufacturing process. The brand’s reputation and online reviews are a good way to judge the quality. However, the long-term warranty is a surefire way to tell whether the panels will last or not.
Products from reputable brands can offer up to 25 years of warranty on performance and manufacturing defects. Remember that a company will honor the warranty as long as it operates. Don’t trust an obscure manufacturer even with a long-term warranty because it can disappear overnight.
How to Get the Return on Investment?
The total cost of solar installation on average for a residential solar panel could be between $15,000 and $30,000. The amount is huge, so it’s normal for people to think about the return on investment (ROI). The utility bills that a solar module saves in its lifetime offset the initial cost. The ROI will be much quicker if you can sell the excess electricity back to the power grid through your energy provider.
Some states even offer tax benefits for solar unit purchase and installation, thus, reducing the initial cost. You will get that advantage if you are living in California, Massachusetts, Maryland, or Arizona.
The Checklist for Buying a Residential Solar Panel
In a nutshell, you should keep these following points in mind when buying a solar module for your home:
- Choose a well-known brand that has been operating for a long time and has a reputation for manufacturing good-quality products.
- Find out the how the unit will perform in the real-life scenario by checking the nameplate rating, positive tolerance, efficiency rating, temperature coefficiency, and LID and PID resistance levels.
- Check the warranty period. Only those companies that have confidence in their products offer a long-term warranty.
The growing demand for the residential solar panel in the United States has reduced the price and made them more affordable than ever. It dramatically increases the return on investment since most units are good enough to produce more power over their lifetime to counterpoise their initial cost. You just have to be careful not to pour money down the drain by purchasing low-end products. They will perform poorly and deteriorate at a faster rate over time than their high-quality counterparts. The mid-range ones offer a good balance between initial cost and long-lasting durability. The high-end models will be the best options because of their high-efficiency ratings and long-term warranties.