Maximizing the value of your roof is one of the most important factors when considering solar. Homeowners and business owners alike are almost always looking to offset as much of their electric usage as possible with their solar array, and often time the amount of roof space is constrained. High efficiency solar panels, like SunPower® panels with their patented Maxeon technology, allow you to get the maximum power density on your roof. More efficient solar panels translate to more savings, flexibility, and long-term peace of mind.

Comparing Production Watt for Watt
Most solar installers use standard efficiency solar panels, which have the ability to convert 15-16% of the sunlight into electricity. These commodity panels are inexpensive as manufactures worldwide have ramped up production to satiate global demand, but oftentimes are made by companies with little to no track record. Although there are some applications where a standard efficiency solar panel may be able to generate all of the electric demand for a home or business in year 1, these panels degrade at a rapid rate.

Standard efficiency solar panels are subject to light induced degradation, which means as soon as they see the light of day they lose 2-3% of their productive capacity. If you look at the manufacturer’s warranty for some of the most commonly used standard efficiency panels (LG, Kyocera, Hyundai, Trina, Canadian Solar, Panasonic, and the list goes on) their Power Output Warranty starts at 97.5% to take account for the light induced degradation. After year one these panels are expected to degrade at 0.8% per year for the next 24 years. This may not sound like a lot, but with a standard efficiency panel you’re looking at a 20% power loss over their warrantied life. This means that as your system ages you will need to buy electricity from the utility company at the rates they are charging 10, 15, 20, and 25 years from now and we know those rates are likely to be significantly higher than today’s rates.

SunPower® panels do not experience light induced degradation and are warrantied to degrade no more than 0.25% per year. This makes a big difference; a SunPower system will make 20% more power watt for watt than a standard efficiency system. This means a big difference in savings when it counts.

Comparing Production on a Constrained Roof
Now that you understand the difference between standard and high efficiency when either one can produce all of the power your need right away, what are the differences when you have a constrained rooftop?

SunPower Solar Panels are commercially available with 22.8% panel efficiency. That is a 46% increase over a typical 15% efficiency panel! SunPower also has a solar panel tested by the National Renewable Energy Laboratory that was verified at 24.1% efficient. You may hear other manufactures talk about about “record breaking” efficiency solar cells, but this is completely different than panel efficiency. Cell efficiency refers to a test that was done in a lab on a single solar cell, but a panel is made up of 60-96 cells and each one of those cells must work together. A single cell in a lab is far from being mass produced and commercially available at a price point that makes installation feasible.

The increased power density means you will have the ability to produce 30-40% more power in year 1 than standard efficiency on the same rooftop and 70% more power over the warrantied life of the system. Don’t need all that power? Increased efficiency leaves room for expansion in the future. Electric cars currently represent 0.1% (1 million electric cars on the road) of the global market, but forecasts expect 100 million electric cars on the road by 2030. Adding an electric vehicle is a perfect compliment to solar and having the flexibility to add to your system in the future in paramount if you plan on purchasing an EV.

More power density also means better returns on your investment. Not every roof is completely shade free, and having the ability to avoid areas of the roof that receive shade from a neighboring building, tree, vent pipe, or chimney will significantly increase the productivity of your system. The more power you generate the more money you will save!

Often times consumers experience sticker shock when comparing a standard efficiency solar system to a SunPower® high efficiency solar system. It is difficult to get an “apples to apples” comparison because one provider may show you a quote for 20 modules that are 250 watts, while a SunPower Dealer could show you 20 modules that are 360 watts! What really matters is the levelized cost of energy, known as LCOE. This represents the cost of the energy, expressed in kilowatt hours or kWh, over the life of your system. A SunPower system will have a significantly lower levelized cost of energy than a standard efficiency system because it produces 70% more power over it’s life on the same size rooftop, SunPower panels have the only 25-year warranty that covers the parts, labor, and power output which means your maintenance costs are $0 over the system’s life, and because SunPower manufacturers the other major components of a solar energy system (inverter and racking) that are also covered by their warranty.

Whether or not you have a constrained roof you are looking for the best value out of your solar energy system, and high efficiency SunPower® solar panels will deliver more energy, savings, flexibility, warranty coverage, and peace of mind than any other panel on the market. SunPower® panels are years ahead of the competition in efficiency so have no fear that you are buying outdated technology. Not all solar is created equal, so make sure you choose a high efficiency SunPower system to maximize your roof’s potential.