Solar
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Plain-language definitions, with the technical detail one click away.
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Common questions
Do solar panels work on cloudy days?
Yes, at reduced output. Diffuse light still reaches the cells, so panels produce a fraction of their clear-day output under cloud.
Is hotter weather better for solar?
No. Panels want bright light, not heat. Above about 25°C, silicon cells become slightly less efficient, so a cool, clear day can beat a scorching one.
How long do solar panels last?
Most panels carry 20 to 30 year performance warranties and lose roughly half a percent of output each year. Inverters usually need replacing once during that time.
Does solar work at night?
Panels produce nothing at night. Homes either draw from the grid or use energy a battery stored during the day.
How much roof space does a home system need?
As a rule of thumb, about 10 square metres (around 100 square feet) of shade-free roof per kilowatt of panels, including spacing.
Is solar energy really clean?
Solar produces no emissions while operating. Manufacturing does cause emissions, but over its lifetime solar emits a small fraction of what coal or gas power does per unit of electricity. The IPCC's lifecycle estimates put utility solar around 48 g CO₂e per kWh, against about 820 for coal.