The demand for solar panels in the United States is at an all-time high, making solar panels more affordable than they’ve ever been. This makes solar a pretty solid return on investment, since most solar panels will produce enough power to offset their initial purchase cost over their lifetime. Not all solar panels are created equal, and generally speaking, a cheaper panel won’t produce power as efficiently as a higher-quality panel. In order to make the best investment for your budget, there are a few factors to consider. Here, we will discuss all of those factors.
If you’re considering installing solar panels to power your home moving forward, there are several things to keep in mind…
Solar Panel Considerations:
Solar panel efficiency represents how effectively a solar panel can convert solar radiation (e.g. sunlight) into electricity. The industry average is 16-18%, but the most efficient solar panels currently available on the market have a solar panel efficiency just under 23%. A higher solar panel efficiency rating means that a panel will produce more kilowatt-hours of energy per watt of power capacity.
Because one high-efficiency panel can generate more electricity than a similarly sized panel with a lower efficiency rating, efficiency is a particularly important factor if you have limited roof space and large energy bills.
The nameplate rating of a solar panel represents the amount of power they produce under industry-standard ideal test conditions. Generally, the solar panels that are commercially available are rated to produce between 200 and 400 watts, depending on the size and quality of the panel. A higher nameplate rating means that the panels are more effective at producing power.
Note that the nameplate rating represents the power output under ideal conditions, which most solar power systems won’t experience, due to variables like sun exposure, the angle of your roof, tree cover, temperature, and atmospheric conditions.
Solar panels come with a tolerance rating that indicates whether the panel will either be below, meet or exceed its nameplate rating. Tolerance ratings are typically expressed as a plus-or-minus percentage. For example, a 300-watt panel with a +/= 5% power tolerance could actually produce anywhere from 285 watts to 315 watts under ideal conditions (as 15 watts is 5% of 250 watts).
A narrower power tolerance range is preferable to a wider one, because it represents more certainty. When evaluating the best solar panels for your home, you should view the power tolerance rating and the nameplate rating together.
Solar panels produce less power in extreme heat. Standard testing conditions occur at 77ºF, and panels lose a percentage of their efficiency as heat increases. So, solar panels are given a temperature coefficient which quantifies how a panel’s power capacity decreases at temperatures higher than 77°F. For example, many standard solar panels may produce 1% less electricity for every 4°F temperature increase above 77°F.
Panels with less sensitive temperature coefficients will perform better over the long term. The temperature coefficient of a panel is much more important for homeowners in hotter climates, and should be considered strongly when comparing panels.
Solar panels can be sorted generally by their cost, efficiency, and durability. The differences between these panels will vary by manufacturer, panel type, and the year they were produced. The International Organization for Standardization (ISO) has created quality assurance standards for the solar panel manufacturing industry known as the ISO 9000 series.
Solar panel manufacturers can be certified ISO 9000-compliant to indicate that they meet those standards. While lack of ISO certification isn’t necessarily an indicator of an inferior product, buying from a certified manufacturer is certainly an indicator of quality.
Most solar panels are very durable, but if you live in an area that has heavy snow or high wind, you should also be sure that the panels you install are designed to withstand the conditions in your area. The International Electrotechnical Commission’s (IEC’s) 61215 reliability standard evaluates panels by performing an accelerated outdoor stress test for panels to ensure their durability. Look for solar panels that meet the IEC 61215 reliability standard to guarantee that they will withstand any weather conditions.
Manufacturers’ warranties are an important when evaluating solar panel efficiency, quality, and durability, because they indicate both technical specifications and business practices. Like all things, solar panels degrade and become less efficient over time. Many manufacturers will guarantee that the power production of their panels doesn’t fall below a certain threshold for a certain length of time. The industry average for the length of time for coverage of solar panels in a manufacturer’s warranty is 10-25 years.
Types of Solar Panels:
There is a wide range of solar panel options on the market today, with low-end, mid-range, and high-end panels being available for your home.
Low-end Solar Panels
Low-end panels are the least expensive panels available. In terms of durability and efficiency, low-end solar panels are generally lacking, so we recommend you invest in a higher quality panel if possible. Most low-end panels have an efficiency rating below 15%. They also come with shorter manufacturer’s warranties, lose efficiency over time faster, and perform poorly in higher temperatures, unlike higher quality panels. They are not a great long-term solution for solar energy, and delay the time it takes for you to see a return on your investment.
Midrange Solar Panels
The majority of solar panels installed on homes in the United States can be considered midrange. They provide a great compromise between initial cost and long-term benefit, meaning you will see a return on your investment much more quickly. Midrange panels are durable and reliable, and usually have an efficiency at or above 15%. Since midrange panels are the most popular, manufacturers generally offer better warranties. With so many options available, you will easily be able to find a midrange solar panel that suits your ideal price, durability, and quality.
If you have the ability to invest in high quality solar panels, you’ll receive exceptional durability and quality, with efficiency ratings as high as 20% and a much longer warranty. These panels also have better temperature coefficients, allowing them operate better in extreme temperatures. This makes them ideal for very hot climates. Their major drawback is their high cost, which can be a deal breaker for some, but know that these panels are a great long-term and cost-efficient investment because of their high quality.