My colleagues will tell you that I am rarely wrong, and my wife will tell you that I rarely admit to being wrong. Well, here it goes. I was wrong!

A while back I wrote that all that matters for making a solar electric purchase decision is dollars per watt. I recently attended a Sunpower sales meeting. I was very surprised about what I learned. Sunpower offers some unique technologies that make the total output of its solar modules greater over their lifetime then competitive technologies. Sun power modules result in lower degradation over time and produce more kilowatt hours then competitive modules.

Although sun power modules cost more than lower-priced competitors the increase in total lifetime energy output makes up for the increase in power/energy.

What really matters is dollars per kilowatt-hour not dollars per watt.

My previous article was somewhat accurate, in that dollars per watt is all that matters in a class of module where deficiencies are generally the same and manufacturing methods are similar. In the case of similar solar module manufacturing technologies, dollars per watt is in fact a good indicator of what you should purchase because generally speaking all module manufacturers use a similar process, similar materials, and have similar energy densities per unit of area.

I was pleasantly surprised that the premium for the Sunpower brand is only around 20% in today’s retail solar market. Between the extra energy produced over the lifetime of a Sunpower panel and the peace of mind gained by having a superior product, I can now recommend this brand despite the higher dollar per watt price of the PV module.

Take a look at these videos from Sunpower that demonstrate the Sunpower Advantage. Once you see the quality and technology that goes into this manufacturer’s products you will understand the rationale for the premium price.