Solar Hot Water Systems vs Electric Hot Water Systems

When choosing a hot water system for your Brisbane home, it's important to understand how solar and electric hot water systems work. Mitchell Plumbing & Gas helps homeowners make informed decisions about their hot water needs.

A solar hot water system uses the sun's energy to heat water through panels or tubes installed on your roof. These panels collect sunlight and transfer the heat to water stored in a tank. The heated water is then ready for use in your home's taps and appliances.

An electric hot water system heats water using an electric element, much like a kettle. The element sits inside a storage tank and heats the water to your desired temperature. It's a straightforward hot water system that has been used in Australian homes for many years.

Solar and electric hot water systems each bring different benefits to your home. While solar hot water systems harness sunlight and may reduce water-heating costs, electric hot water systems offer reliability and simpler setup. Understanding these differences helps you pick the hot water system that best matches your household's needs. Here's how they measure up in important areas.

• Energy Use and Running Costs: Solar collectors can reduce the purchased energy needed for water heating, but gas or electric boosting still adds to running costs. Compare the selected systems using your hot water demand, available sunlight, booster use and energy tariffs.
• Installation Costs: The upfront cost of solar hot water systems is higher because of the panels, tank, and more complex installation process. Electric hot water systems are cheaper to buy and install because they're simpler. The initial investment varies based on hot water system size and home requirements.
• Maintenance Requirements: Both solar and electric hot water systems need routine maintenance according to their owner's guides. Solar collector care depends on the model and local conditions. Electric storage systems also need scheduled safety-valve and tank maintenance, even when they appear to be working normally.
• System Lifespan: Service life varies with the model, water conditions, usage and maintenance. Compare the complete systems rather than assuming solar will always outlast electric.
• Heat-Up Time: Heating time depends on the model, the water being reheated and available energy. Solar systems also depend on sunlight and their gas or electric booster. Stored hot water can be used before a full-tank reheating cycle is complete.
• Noise Levels: Sound depends on the specific equipment and installation. Neither type is guaranteed to be silent.

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What Is A Solar Hot Water System? 

A solar hot water system is a water heating setup that turns sunlight into heat for your home's water supply. This hot water system catches the sun's warmth through collectors fixed on your roof. Inside these collectors, there's a special fluid that warms up in the sunlight. As this fluid gets hot, it moves down into a tank and passes its heat to your household water.

The main parts of a solar hot water system are:

• Solar collectors (flat panels or tubes) that soak up the sun's heat
• A storage tank with special insulation to keep water hot
• Pipes that connect the collectors to your tank
• A pump that moves the heating fluid through the hot water system
• A controller that manages the whole process

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What Is An Electric Hot Water System? 

An electric hot water system is a water heater that uses electrical power to warm your water. The hot water system works by passing electricity through heating elements inside a tank. These elements heat up like a big kettle and warm the surrounding water to the temperature you want.

The main parts of an electric hot water system are:

• An insulated storage tank that holds the water
• One or two heating elements that warm the water
• A thermostat that keeps track of water temperature
• Cold water inlet and hot water outlet pipes
• A temperature pressure relief valve for safety

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What Are The Differences Between Solar And Electric Hot Water Systems?

The main differences between solar and electric hot water systems show up in how they work, what powers them, and what they cost to run and install.

• Energy Source: Solar hot water systems use sunlight with gas or electric boosting. The electric systems compared here use resistance heating and can draw power from the grid or rooftop solar PV, depending on the setup.
• Efficiency: Solar contribution and appliance conversion efficiency measure different things. Compare complete-system energy use, including boosting and heat losses.
• Installation Process: Solar hot water systems need roof access and more complex setup work. Panels must face the right way to catch maximum sunlight. Electric resistance storage systems need suitable electrical and plumbing connections, safety devices, drainage and service access.
• Cost: Solar hot water systems can cost more upfront and may reduce ongoing water-heating bills. Compare installed quotes and estimated running costs for your household before deciding whether future savings justify the extra purchase cost.

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Energy Efficiency Differences Between Solar And Electric Hot Water Systems

Solar contribution is the share of water heating supplied by sunlight. It varies with climate, collector installation and demand. Rheem's solar FAQs explain that gas or electric boosting supplies heat when sunlight is insufficient.

Electric resistance-storage systems heat water with an element and can use grid electricity or solar PV. Element efficiency alone does not account for heat lost from the tank and pipework.

Compare energy use for the same household demand, including:

• Local sunlight and collector shading
• Hot-water use and storage heat losses
• The amount of gas or electric boosting needed
• Electricity supplied by the grid or rooftop solar PV

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Installation Cost Differences Between Solar And Electric Hot Water Systems

Installation costs cover everything needed to get your hot water system working safely in your home, from the equipment itself to the professional labour required. Solar hot water systems typically come with a higher upfront cost because they need rooftop collectors, storage tanks, and more complex installation work. Their placement also needs careful planning to maximise sun exposure.

Electric hot water systems have a lower initial cost because they need simpler equipment and installation work. The installer must check the selected model's electrical and plumbing connections, safety devices, drainage and service access.

Eligible solar hot water installations may qualify for Small-scale Technology Certificates (STCs). The selected model must be on the relevant register, and the installation must meet scheme requirements, including applicable installer licensing. Assigning the right to create STCs to a registered agent may provide an upfront discount. This is not an automatic cash rebate or a fixed discount; check the Clean Energy Regulator's eligibility guidance and your quote before committing.

There is no single annual saving or payback period that applies to every home. Compare the installed-price difference after confirmed incentives with the estimated annual running-cost difference between the systems you are considering. Allow for hot water use, solar exposure, boosting, tariffs and maintenance. Rheem's solar hot water guide explains how savings depend on the system replaced, location, use and tariffs. Ask for the assumptions behind any savings estimate, including which existing system it is compared with.

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Required Maintenance Differences Between Solar And Electric Hot Water Systems

Maintenance means keeping your hot water system working safely and efficiently through regular checks and servicing. This helps prevent breakdowns and extends the hot water system's life.

Solar hot water systems need collector care and servicing according to the manufacturer's instructions and local conditions. Have a qualified technician assess the collectors, roof mounting, tank, connections and booster as required for the model. Follow its relief-valve and anode maintenance schedule. Solahart's thermosiphon owner's guide gives one model-specific example.

Electric storage systems need scheduled maintenance according to the manufacturer's instructions. Relief valves, the tank and any anode need attention at the specified intervals; water conditions can affect the schedule. Leave electrical inspection and repairs to an appropriately licensed professional. Follow the owner-maintenance instructions for your model and only perform owner checks where safely accessible. Relief-valve discharge can scald: stay clear of the outlet, never block its drain and ask a licensed plumber if unsure.

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Average Lifespan Differences Between Solar And Electric Hot Water Systems

A hot water system's lifespan is the period it remains in service before replacement. Solar collectors, the storage tank and any booster are separate components, so the age or condition of one component does not establish the lifespan of the whole system.

Electric storage systems also vary in tank construction and operating conditions. Using an electric heating element does not, by itself, establish a shorter service life than a solar system. Compare the selected models and their condition.

Water chemistry, pressure, water temperatures and usage patterns can affect service life. Solahart's split-solar owner's guide (page 17) and Rheem's electric-storage owner's guide (page 15) describe these factors. Follow the maintenance guidance for the particular model rather than relying on a fixed lifespan for either category.

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Heat-Up Time Differences Between Solar And Electric Hot Water Systems

Solar heating varies with sunlight, weather, collector conditions and hot water use. Gas or electric boosting can provide additional heat when solar energy is insufficient. There is no single solar-only full-tank heating time that applies to every system.

Electric storage reheating time depends on the water volume, element power and incoming water temperature. Rinnai's reheating FAQ also identifies the electricity supply arrangement as a factor. An off-peak or timed system may not be able to reheat throughout the day.

For daily use, compare the stored hot water available with your household's demand and the selected model's recovery information. Check how its booster works: some arrangements reheat only part of the tank, so boosted hot water availability does not establish a full-tank reheating time.

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Noise Level Differences Between Solar And Electric Hot Water Systems

Solar hot water systems are not always silent. Pumped systems have a circulation pump, and solar collectors can also make sounds under some operating conditions. Rinnai's split-solar manual describes possible collector noises during high solar gain.

Electric resistance hot water systems may hum when their elements heat, and pipework can click as it expands or contracts. How noticeable these sounds are depends on the installation and background noise. Compare the specific equipment and proposed location rather than assuming one type will be quieter.

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Environmental Impact Differences Between Solar And Electric Hot Water Systems

Solar collectors use renewable sunlight, but the complete system is not emission-free. Operating emissions depend on boosting and the energy supply.

Electric water heating does not burn fuel at the appliance. Its indirect emissions depend on electricity generation, including any rooftop solar supply. The Clean Energy Regulator explains direct and indirect emissions. Compare specific systems and usage rather than assuming a fixed annual emissions figure or environmental ranking.

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What Are The Overall Pros And Cons When Comparing Solar And Electric Hot Water Systems?

A clear comparison of both systems helps understand their strengths and limitations across different aspects:

Solar Hot Water Systems:

• Efficiency: Solar contribution varies with the installation and household
• Installation: Complex setup requiring professional installation
• Cost: Higher upfront cost may be offset by lower water-heating bills, depending on the home and system
• Noise: Varies with the system, booster and installation
• Environmental Impact: Depends on boosting and the system replaced

Electric Hot Water Systems:

• Efficiency: Include storage losses when comparing electricity use
• Installation: Requires suitable electrical and plumbing connections, safety devices and service access
• Cost: Compare the installed price and expected electricity costs for your usage and tariff
• Noise: Element hum and pipework sounds may occur
• Environmental Impact: Depends on electricity use and supply

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What Are The Advantages Of Solar Hot Water Systems?

Solar hot water systems provide several advantages when compared to electric hot water systems:

Potential Water-Heating Savings:

• May reduce water-heating bills; savings vary by system and household
• Less purchased energy may reduce exposure to price rises, but boosting still has a cost
• Running costs depend on booster use, hot water demand and tariffs
• Free energy from the sun
• Payback depends on the extra installed cost after confirmed incentives and actual annual savings

Environmentally Friendly:

• Solar collectors use sunlight without burning fuel
• Uses renewable energy source
• May reduce operating emissions, depending on boosting and the system replaced
• Supports sustainable living
• May reduce grid electricity use, depending on the systems compared

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What Are The Advantages Of Electric Hot Water Systems?

Electric hot water systems offer distinct benefits in certain situations:

Consistent Performance:

• Reliable hot water delivery
• Works in all weather conditions
• Even water temperature
• No reliance on sunlight

Practical Benefits:

• Lower upfront purchase costs
• Simple installation process
• Needs a suitable location with the model's required service access and clearances
• No roof space needed
• Easy maintenance access

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