Do Solar Geysers Work in Winter and During Load Shedding?

Short answer: yes. Evacuated-tube solar geysers heat water from sunlight, not air temperature, so they keep working on cold, clear winter days. They also heat water during load shedding because the tubes need no electricity. On long overcast spells a small backup element tops up the heat.

How evacuated tubes work in winter

Each tube is like a vacuum flask: an inner glass tube absorbs sunlight, and the vacuum between the two glass layers stops the heat escaping. That is why tube collectors still perform well on frosty Highveld mornings, as long as the sun is out.

Winter days are shorter and the sun is lower, so expect less hot water than in summer. Point the collector north and tilt it at roughly your latitude plus 10–15° to catch more winter sun.

During load shedding

• The tubes keep heating water whether Eskom is on or off.
• A low-pressure solar geyser works by gravity, so it keeps supplying hot water with no power at all.
• The backup element only matters when the sun hasn't been out. Use a timer or a smart controller like the SR609C so it runs only when needed.

Cloudy and rainy days

Tubes still collect some heat through thin cloud, but on heavy overcast days the element does most of the work. A well-insulated tank holds yesterday's heat overnight, so one cloudy day rarely leaves you with cold water.

Tips for frost areas

• Insulate all exposed hot and cold pipes.
• Choose a slightly bigger geyser so stored hot water lasts through cold snaps.
• Ask us about the right setup for your area before installing.

See our low-pressure solar geysers and retrofit kits, or read What size solar geyser do I need?

The Sun Pays has supplied solar power, AC and DC water pumps and solar water heating across South Africa since 2007, with our own South African technical team for advice, repairs and support. Questions? WhatsApp 082 515 1655, call 012 734 0915 or email sales@thesunpays.co.za.

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