Yes, solar vacuum tubes do not produce as much energy on cloudy days, so a backup power source might be necessary to ensure a consistent supply of electricity.
No, solar vacuum tubes do not require a backup power source during cloudy days as they are designed to still generate heat and produce hot water even in low light conditions.
Yes, solar vacuum tubes do not require a backup power source during cloudy days. While their efficiency may be reduced, solar vacuum tubes can still generate heat and produce hot water even in cloudy conditions.
