Homeowner Blog

SunPower Solar Panels: Maxeon 3 Breaks the 400W Barrier

Erica Charles · 17 Mar 2019

In January SunPower introduced the world’s first 400 Watt residential solar panels.

Utilising 104 Monocrystalline Maxeon Generation III solar cells, the panels have an efficiency of 22.6%. 

The panels have ‘standard’ panel dimensions of approximately 1.69m x 1.05m, giving an output of 226W per square metre.

As always with SunPower, the panels have a premium look…

Sunpower Maxeon 3 white Sunpower Maxeon 3 black
Maxeon® 3 - White Maxeon® 3 - Black

35% more efficient than standard panels, up to 60% more lifetime output

By way of comparison, low cost ‘standard’ sized polycrystalline panels typically have an output of 168W per square metre

In addition, the output from SunPower Maxeon® solar panels degrades at a much lower rate (around 0.25% per annum for Maxeon® and 0.6% for Performance, instead of the standard 0.70% degradation). Furthermore the panels exhibit superior performance in hot rooftop conditions, and in partial shade.

For example, the temperature coefficient (reduction in power output at cell operating temperatures above the ‘standard’ operating temperature – usually 45°C) is -0.29% for SunPower's Maxeon® panels, compared to -0.39% for a standard polycrystalline panel, and -0.37% for the SunPower Performance range. It doesn't seem much, but it all adds up over 25 years...

Overall SunPower claims that a Maxeon® 3 SunPower panel will produce as much as 60% more energy out of the same space over the life than a similar rated standard panel.  

Higher Lifetime Output Sunpower Maxeon 3

25 year warranty

SunPower also offers a superior warranty with all of its panels, summarised in this table:


SunPower Maxeon®

‘Standard’ solar panel

Panel (Defects)

25 years

10 years




- Year 0



- Annual decline



- Year 25






Shipping – old panel



Shipping – new panel



Installation – new panel*



 *SunPower will pay for reasonable, necessary and actual removal and re-installation costs of the repaired or replaced PV module up to 250 Euros for up to 5 PV Modules, and 50 Euros per PV Module thereafter for a single claim.

SunPower, extends the defects cover over 25 years and guarantees that their Maxeon® 3 panels will output 92% of their original output at the 25-year mark, rather than the 80% of the standard panel. 

Do SunPower panels make sense on economic grounds alone?

Certainly the answer is likely to be 'yes' if space is a limiting factor. As above, SunPower claims you will get 60% more output from the same space - around 35% due to higher efficiency, and the rest due to better performance characteristics.

If space is not a limiting factor, then SunPower may not be justified on economic terms alone. It depends on the overall cost of the installation (which in turn depends on scaffolding costs, cable runs, economies of scale etc). The panels will add approximately 45% to the cost of a typical small scale installation using a standard polycrystalline panel, and so SunPower is unlikely to make sense on economic grounds alone. However, once you take into account the way superior aesthetics (smart black versus dark blue) and the superior warranty (backed up by the fact that SunPower is 60% owned by energy giant Total), the premium panel may well be worth paying for.

The full SunPower panel range

SunPower's current panel range is summarised in the table below. For datasheets and for more information on the range, price comparisons, the cell technology, visit our dedicated SunPower panel page.


Output per panel



Maxeon® 3


1690mm x 1046mm


Maxeon® 2


1690mm x 1046mm


Performance Residential


1690mm x 998mm


Performance Commercial


2067mm x 998mm


For Comparison: ‘Standard Polycrystalline’


1650mm x 992mm


Request a quote

If you'd like a quote for installing SunPower panels (or anything else...) email us on info@spiritenergy.co.uk, call us on 0118 951 4490, or click here to fill in our online form:

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Topics: Solar PV