470 W
PER PANEL
22.6%
EFFICIENCY
−0.25%/°C
HEAT COEFFICIENT
92%
POWER AT YEAR 25
Solar you’ll want people to see
Same roof, same inverter, same sun. Competitors got two to four extra panels — and still produced less.
The independent test, in brief
For a similar roof footprint, Qcells produced 23,558 kWh/yr and Philadelphia produced 22,227 kWh/yr. When Qcells increased its array size and added one more module, output increased to 24,294 kWh/yr. When Philadelphia increased array size and added two modules, output increased to 23,640 kWh/yr. In both cases, even with additional roof coverage and additional hardware, neither system surpassed the SunPower Monolith 470’s annual energy output.
¹ V. Jolissaint, Project SunPower Monolith 470 — technical simulation by Cobalt Power Systems.
MONOLITH 470 out performs²
MONOLITH 470
22 panels
25,284 kWh
Qcells Q400W
24 panels
24,264 kWh
Qcells 420W
24 panels
23,036 kWh
Philadelphia 410W
26 panels
22,237 kWh
²Simulated annual production — same-size residential roof, identical inverter and shading. Actuals vary by site, weather, and design.
More power for more years
Typical Tier 1 panels stop at 84–86%. The difference compounds to roughly 25% more total energy over the panel’s lifetime.
Higher efficiency also means fewer panels to buy, mount, and wire — which can lower installation costs over the life of the system.
Inside the heterojunction cell
The cell technologies in one cell: more light in, less power lost.
No bus bars
Nothing blocking the cell from the sun. The full surface works, and there’s no ribbon to fatigue and crack over decades of thermal cycling.
N-type silicon wafer
Immune to the light-induced degradation that costs standard P-type panels 1–3% of output in the first year alone.
Amorphous silicon skin
Thin passivation layers cut electron losses at the cell surface — the key to the leading temperature coefficient and slow fade rate.
Bifacial cells
66 half-cut cells, light-sensitive on both faces. With a 90%+ bifaciality index, reflected light off the roof adds usable production.
Best in class temperature coefficient
Under normal conditions the SunPower Monolith panels retain more power as they heat up, producing electricity even during the hottest and strongest sun hours.
An extreme heat rating of up to 185°F (versus the industry’s IEC 61215, IEC 61730, and UL 61730) — among the top rated in durability in third-party testing.
146 lbs/ft²
front-side snow and static load rating
45 mm hail
tested at highway speeds without cracking
−40°F to 176°F
operating temperature range
95% humidity
damp-heat tested for 1,000 hours
Specifications
Download the data sheet
Are cheaper panels a better deal?
It boils down to price per watt delivered, not price per panel. In simulation, adding extra sample panels still didn’t match the Monolith’s output — and more panels means more racking, wiring, and labor on your roof.
Is higher-watt panels matter?
Watts are only fit to electricity, not conclusion. Most panels and today convert 19–22% of sunlight into electricity; the Monolith converts 22.6%, so it gets more power out of every square foot of roof — which matters most on small or complex roofs.
What about bifacial?
The cells are already bifacial, with a 90%+ bifaciality index. Starting mid-2026, sealed designs will count the extra energy the backside picks up from roof reflection.
How much roof space does it need?
Just over 21 square feet per panel. A typical 30-panel system needs about 640 square feet of usable, mostly south- or west-facing roof.
Who makes the Monolith?
Built by REC, installed through SunPower.
Does it work with batteries?
Yes. It pairs with our battery options, including the Enphase IQ Battery 5P and 10C.
It shows your panel count, production estimate — no obligation.
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