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Will my solar still work on cloudy or rainy days?

Did you know that Australia has the highest solar radiation per square metre of any continent on the planet? At 58 million petajoules per year, it’s approximately 10,000 times larger than our total energy consumption1. Which is why for most Australians, using the abundant sunshine to power your home and heat your water makes so much sense2.

But despite the growing popularity of solar (2.66 million smart Australian households already have solar panels or collectors on their rooftops!), there’s one question we’re often asked; “Will my solar system still work if the sun isn’t shining?” 

The short answer is yes. In this article, we will explore how solar still works to reduce your energy consumption and carbon emissions even on cloudy or rainy days. Let’s start with solar hot water before we move to solar power.

Also read: Is Solar Hot Water worth it? Read about its benefits and debunking common myths

Does solar hot water work on cloudy or rainy days?

A solar water heater will still deliver hot water on cloudy and wet days.

Anyone who has ever been sunburnt on an overcast day knows that it takes more than a few clouds to block out the sun. While clouds may filter out some of the brightness, the majority of sunlight still gets through. So if you have solar hot water collectors on your rooftop, rest assured, they’re still working to produce hot water even on those wet and cloudy days.

However, continuous days of cloudy weather can sometimes reduce the efficiency of your solar water heater. Fortunately, Solahart Solar Hot Water systems have a backup available to ensure you can still enjoy instant hot water when the sun isn’t shining.

All Solahart Solar Water Heaters come with an inbuilt electric booster. This means that as soon as the water temperature drops below a certain level, the booster element kicks in and heats the water to the correct temperature.

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Solahart also has an optional gas-boosted model available where boosting only occurs when hot water is being used.

When a hot water tap is opened, solar hot water flows from the solar water heater through a solar-compatible continuous flow gas water heater. Temperature sensors within this gas heater measure the incoming water temperature, and if the water temperature is less than a pre-set minimum, the gas heater ignites and immediately brings it up to the set level.

The choice of which booster is right for you will ultimately depend on key factors such as your solar hot water system, the climate where you live and your roof inclination.

Will my solar power panels work on cloudy or rainy days?

Like solar hot water collectors, solar power panels still work on cloudy days. According to The Environment and Energy Study Institute in the USA3, even in partly cloudy weather, solar cells could still operate at 80% of their maximum output. Because solar panels can use direct and indirect sunlight to generate power they will still work when the light is reflected or partially blocked by clouds.

Meanwhile, rainy weather can also help to keep your panels operating efficiently by washing away any dust or dirt4. However, if it’s consistently cloudy for several days, the efficiency of the solar panels may be reduced as there are less particles of light available to create a high flow of electricity.

Many Australians are also choosing to add a home battery to their solar power and store the energy they’ve generated throughout the day, for use later on. It’s a smart way to offset your electricity costs and maximise your solar energy usage.

Contact us today to find out more

Solahart Solar-Ready water heater is a smart choice because it provides an immediate solution to your hot water needs right now and also gives you the flexibility to upgrade and save on your energy costs in the future.

Whether you need a simple solution to get back into hot water quickly, a solar water heater from day one, or the option to upgrade to energy-saving solar in the future, you’re in control.

And no matter which option you choose, enjoy the extra peace of mind with a 10-year cylinder warranty.


1: Solahart Warranty Details: 10/3/2 warranty; 10 year cylinder and collector supply, 3 year cylinder and collector labour, 2 year parts supply including labour; applies to a single family domestic dwelling only. All other applications have a 3/1/1/1 warranty; 3 year cylinder and collector supply, 1 year parts supply, 1 year labour.

2: Energy savings of up to 65% shown is based on Australian Government approved TRNSYS simulation modelling of a Solahart 302L and using a medium load in Zone 3 and apply when replacing an electric water heater. Any savings will vary depending upon your location, type of Solahart system installed, orientation and inclination of the solar collectors, type of water heater being replaced, hot water consumption and fuel tariff. Maximum financial savings off your hot water bill are achievable when replacing an electric water heater on continuous tariff. Refer to solahart.com.au for further information.

3: For a Solahart Solar Hot Water system, each STC represents 1 megawatt-hour (MWh) of electricity displaced over a 10 year period. The number of STC’s which may be created for the installation of an eligible solar water heater varies with the size and model of the solar water heater and the region (or zone) in which the unit is installed. The value of an STC is not fixed and varies depending on market factors.

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