Solar Hot Water : Why don’t I have hot water when it’s cloudy?

no hot water when cloudy

No solar hot water when it’s cloudy?

Solar hot water system troubleshooting tips.

After weeks of hot weather and ample sunshine, as soon as we experience a few days of rain and cloudy skies we are guaranteed to receive an increase in phone calls from solar hot water customers complaining they have no hot water all of sudden. Many are often perplexed as to why their solar hot water supply seems to come and go – one day they have ample hot water, then the next none. Why does this happen?

Why do I run out of solar hot water when it’s cloudy?

Solar water heaters work by absorbing energy from the sun’s rays in the roof mounted solar collectors and transferring this to heat water stored in the tank.

Ground mounted direct systems rely on an inbuilt circulator to push the water through the system, whereas roof mounted systems rely on a natural ‘thermosiphon’ effect. Water passes through the solar collector where it is heated, then moves out of the collector and into the tank. The tank gradually gets hotter until the water reaches its maximum stored temperature.

All solar hot water systems come with a gas or electric back-up system that will continue to supply hot water during cloudy days and prolonged periods of low sunshine. If there is a problem with the backup systems then, on cloudy days when there isn’t enough sunshine to heat the water via the suns rays, you are likely to run out or experience no hot water.  Then, when the sun returns, so does your hot water supply.

When we experience weeks of sunny skies and warm temperatures, many people don’t even realise there is a problem with their solar hot water system. It is only once we have a few days of inclement weather that this is brought to their attention and hence we receive an influx of calls from perplexed solar hot water users.

The problem is usually not with the entire system, just the gas or electric backup.  Typically the repair involves replacing the broken or worn parts and the customer is back experiencing trouble-free solar hot water – rain, hail or shine!

Solar hot water problems?

We are the Sydney solar hot water experts. We are authorised installers and repair technicians for all the solar hot water heater brands including SolahartRheemEdwardsApricusQuantum and many more.  Our solar systems are competitively priced because we purchase large quantities direct from the manufacturers – a saving we can pass on to our customers.


The information on this website is of a general nature only. We do not make an warranties about the completeness, accuracy or reliability of this information or whether it is relevant to your specific hot water problem(s). For professional hot water repair advice specific to you, contact our Sydney hot water specialists direct on 0410 693 532.

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Why we’re the Sydney solar hot water specialists

Hot water is our business and that’s why, when you deal with our highly-skilled, solar hot water specialists, you’re assured of service and expertise that is second to none.

  • Hot water is our business and we are Sydney’s leading solar hot water specialists.
  • Our fully qualified, licensed hot water heater repair specialists each have over 25+ years experience.
  • We are accredited service agents for all solar hot water brands including Rheem, Apricus, QuantumEdwards SolarSolahart and more.
  • We are a local, Australian-owned, family-run business offering reliable, old fashioned service.
  • If your current solar hot water heater is beyond repair we offer free delivery of a new system and complimentary disposal (and recycling) of your old water heater.
  • We are qualified to undertake all the plumbing and electrical work required to install a new hot water system. There is no need to waste money employing multiple trades.
  • We have all the equipment needed to install your hot water system today. We don’t have to hire or wait for other trades to arrive with the required equipment.

For helpful advice about choosing the right solar hot water system, use the quick links below:

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