- Cost per watt: $3.30–$3.74
- Warranties: 25-year product and 25-year performance
- Efficiency: 20.1%–30%
SunPower uses its own in-house manufacturing company, Maxeon, to supply solar panels. Its high-efficiency panels feature some of the lowest rates of degradation. These higher efficiency rates mean you could use fewer panels to produce your home’s required electricity, which may lead to a more cost-effective installation on a small rooftop. Overall, though, SunPower’s products are more expensive than most competitors.
Pros and cons of SunPower
+ Features the highest efficiency rating of providers on this list
+ Offers an above-industry performance guarantee of 92% for up to 25 years
+ Has partnered with NASA and Honda in the past
– Is a more expensive option
– Can only be installed by one of SunPower’s certified companies, which may limit your choices for installation providers
– Is soon to be facing a class-action lawsuit due to significant losses from cracking issues with its connectors
We contacted SunPower about these cons, and the company stated that “to make high-quality solar mainstream, [it] recently introduced SunPower Financial, an in-house financial services institution designed to make renewable energy affordable for more American homeowners.” In regards to its limited choice of installation providers, it commented that it uses its dealer base of nearly 700 small and medium-sized businesses to “ensure [they] meet [SunPower’s] quality and customer service standards.” SunPower also stated that it does not comment on active litigation, but that lawsuit in question did not impact residential solar systems.
SunPower has four solar panel lines:
- M Series — A high-power panel with built-in microinverters to convert energy from direct current (DC) to alternating current (AC) electricity
- X Series — A high-range efficiency panel with either white or black backing that is a good option for smaller rooftops
- E Series — SunPower’s standard panel with mid-range wattage and efficiency
- A Series — Powerful monocrystalline panels with white or black backing that generate up to 420 watts
SunPower solar panels tend to be pricier than most. They are the most expensive brand on our list. SunPower panels feature a minimum price of $3.30 per watt, which is already more than the industry average of $3 per watt. Therefore, a 6 kW system with SunPower runs on the high end between $19,800 and $22,440.
SunPower does provide an impressive guarantee, though. The company states that its panels will perform at least 92% of their original output capacity for up to 25 years. If not, SunPower will cover any maintenance or repairs if your system is performing at a lower level at any point during 25 years.
Note: We reached out to each manufacturer on this list for a comment on the cons listed in this article. Unless otherwise noted, we did not receive a response from the brand.