Panelwise kWh
Solar, measured

Every solar decision is a number you can check.

Panel efficiency, inverter losses, payback periods, degradation rates. We work them out in the open and show where each figure comes from, so you can argue with the maths instead of trusting a sales pitch.

Read the guides Start with the basics →

Daily output curve of a 5 kilowatt rooftop solar array Output rises from zero at 5am, peaks at 4.1 kilowatts around solar noon, and falls back to zero by 7pm, totalling 22.6 kilowatt-hours for the day. 06:00 09:00 12:00 15:00 18:00 4.1 kW peak
One clear October day, 5 kWp array, 32° tilt facing south. This is the shape every solar calculation is really about.
5.0 kWp Array size
4.1 kW Peak output
22.6 kWh Harvested that day
82 % Peak vs rated
Why the tables matter

We publish the spec sheet, not the brochure

Panel marketing leads with peak efficiency because it is the flattering number. Temperature coefficient and degradation rate decide what you actually harvest over twenty-five years.

Typical residential module characteristics by cell technology, 2026
Technology Efficiency Temp. coefficient Annual degradation Area per kWp
Monocrystalline PERC 20–22 % −0.34 %/°C 0.50 % 4.7 m²
Monocrystalline TOPCon 22–23 % −0.29 %/°C 0.40 % 4.4 m²
Polycrystalline 15–17 % −0.39 %/°C 0.60 % 6.1 m²
Thin-film CdTe 14–16 % −0.25 %/°C 0.40 % 6.9 m²

These are typical ranges, not a substitute for the datasheet of the specific module you are quoted. REPLACE the figures above with values you have cited to a primary source before publishing — a sourced table is the whole point of this section. For the full comparison, read monocrystalline vs polycrystalline vs thin-film.