Everything you need to know about solar hot water: A comprehensive guide

Solar hot water. It’s good for the environment, your wallet, and it’s just plain interesting. Find out all you need to know, here.

It takes a LOT of energy to heat up water. It takes over four times the energy to heat water than the same amount of air. For your household, heating water is likely the largest source of carbon emissions and energy consumption, around 25—30% of energy usage for a typical home. Installing a solar hot water system can save the average Australian family between $300—$700 in electricity bills.

It is for these reasons that solar hot water is becoming more and more popular among Australians. Read on, to learn more about solar hot water and how it might fit into your lifestyle.
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Based on Baseline Energy Estimates 2008.

What are the components for a solar hot water system?

Solar hot water systems catch energy from the sun, store that energy in water and store that water for later uses around the home like hot showers and dishwashers. These systems take the pressure off of traditional gas or electricity-powered hot water systems like boilers.

Solar collector

First and foremost, a system is composed of a solar collector/collectors. This technology is responsible for capturing the sunlight and stopping it from escaping. This is also where the heat exchange takes place, where the Sun’s heat is used to warm the water.


This is where the heated water is sent for storage once it has been heated.

Solar booster

Solar boosters can be added on to your set up to make the most of your solar collecting water system. They can be powered with either gas or electricity, and can heat your water when the sun is not around, either from cloud cover or nightfall. Solar boosters are advantageous and can sometimes be necessary, especially taking into consideration the investment made into a pre-existing boosterless system.

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What do I use hot water on?

Hot water is used to clean things: your dishes, your clothes, and your body. In fact, around a third of your hot water usage comes from your time in the shower.

What are some other considerations regarding solar hot water installation?

When planning your system, think about how to minimise heat loss. Just as you wouldn’t eat an ice cream next to a campfire, like-temperature elements should be grouped. The components of your hot water system should be kept close to each other to conserve heat: the solar collecting panels should be placed near where the hot water will be stored (to shorten pipeage), both of which should be placed where the hot will be used, i.e. the kitchen, bathroom, and laundry.

How do I install my solar hot water system?

Collecting panels need to be mounted on a shade-free surface, facing north, and tilted approximately 35 degrees from completely flat, these suggestions vary depending on your specific location. Since many systems consist of a weighty storage tank that resides on the roof, professional installation is necessary to ensure structural integrity. Installation costs vary, and can sometimes cost as much as the system itself, so make sure to factor this into your solar hot water budget.

What are some companies that offer solar hot water installation, and how can I get a quote?

Rinnai, Solahart, EnergyAustralia, Apricus, Rheem all provide solar hot water options. You can visit their websites to get a quote.

What types of solar hot water systems are there?

Flat-plate vs. evacuated tube

There are various designs of solar collector, but two are more common. The flat-plate systems are an earlier design and the most common type. They consist of various layers of material that absorb the sun’s heat, and trap it between the layers to heat pipes bearing water (or other conductive fluid). The pipes take this heated water and deliver it to an insulated storage system.

Evacuated tubes operate similarly, but instead of a flat bed of absorbing material, the system is composed of repeating tubes. Due to the cylindrical design, the tubes are exposed to more sun throughout the day as it rises and falls. Further, the evacuated (vacuum) design stops heat from escaping, thus increasing the efficiency of the design.

Evacuated tube systems can be costlier than flat-plate systems, but can often save money in the long-run.

Are there any solar hot water rebates?

In same states and territories, the Australian government offered rebates for residents to switch over to solar hot water. There were a variety of rebates that varied by state, but most, if not all rebate offers have ended. For more information, you can visit the governmental site Hot Water Rebate.

How long does it take to install a solar hot water system?

Installing a solar hot water system typically takes as little as 2-3 hours, though this will vary depending on your system and location. You can discuss practicalities like this with a specialist energy consultant or with your system provider.

How many people does a solar hot water system supply?

Typically, a 300-litre system will serve a home of between four to six people. If you’re in a bigger home, or think you’re an above-average user, then higher-capacity gear or multiple systems can also be installed. Remember that all systems come with an electric or gas booster, which will ensure hot water is available all hours of the day regardless of the weather.

How much money will I save?

This will depend on your home location and usage, but it is estimated that the average family home could save up to $920 per year on their water heating bills by using solar.

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What are RECs (Renewable Energy Certificates)?

RECs are certificates that are awarded to qualifying solar hot water systems. They are a government initiative that is designed to encourage the use of products that reduce greenhouse gas emissions. RECs are traded on the market by energy companies, who buy them from renewable energy producers (including homes and business that own efficient systems). If you get a solar hot water system, you may be able to sell your REC to the supplier or installer, or sell them to a different buyer of your choice. The price of sale will vary depending on your systems; you should talk to a solar hot water installer or a specialist energy consultant to find out more.

If the system is damaged in a storm or by accident, am I covered by insurance?

This will vary depending on your insurance policy. Solar systems are often covered by standard household insurance, but don’t assume that this is automatically the case. Contact your insurer and check the terms of your policy, and make changes to expand your cover if necessary. The last thing you want is to have to dip into your own pocket to cover any accidents.

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