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Gas Boosted Solar Hot Water Systems: Complete Guide and FAQ

High-efficiency gas boosted solar hot water systems are one of the most economically and environmentally friendly ways to keep your home’s hot water supply in shape all year round. Although it is a bit more common to see electric systems around the country today, natural gas boosted solar hot water heaters are often the right choice for many homes and buildings throughout Australia. 

Below, we will explore the components, benefits, and considerations of installing a gas boosted solar hot water system before answering some of the most common customer questions from Australians today.

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Solar Hot Water Systems 101

As most homes down under receive more sunlight than they know what to do with, solar hot water systems are extremely common on rooftops across the country. Today, there are two distinct kinds of solar generators to consider for your home: photovoltaic (PV) solar panels or thermal solar collectors. 

PV solar panels are used to generate electricity which can be used in the home and/or sent back to the electrical grid. While PV solar panels can also be utilized to assist an electricity boosted solar hot water system, the primary component of any solar heating installation is the thermal solar collectors. 

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Thermal Solar Panel Collection 

A solar hot water system uses thermal solar collectors to generate usable energy. While humans have been harnessing the sun’s heat for their water supply for over a dozen centuries,  there are several high-efficiency technologies that have been popularized around the world in the last few decades.  

Today, solar hot water systems typically use an array of flat plate or evacuated tube collectors to collect the heat from the sun and transfer it to the rest of the system. While both technologies have various models, pros, and cons, evacuated tube generators are generally seen as the premium choice for high-efficiency systems. 

Heat Transfer, Water Storage, and Household Use

In most solar hot water systems, the energy from the sun is sent to a special “heat transfer fluid” which is then passed on to the home’s water supply. Alternately, other systems are designed to heat the water directly with the sun’s energy (i.e. passing through the collector) and continuously moving it through the home’s pipes and appliances. 

Within the tank, the hot water is then stored in an insulated environment, specifically designed to maintain heat levels overnight while new solar energy is not available. Once installed, solar hot water heaters operate as normal, and using the system is as simple as running the taps within the home. 

Gas Boosted Solar Hot Water Systems

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In a gas-assisted solar hot water system, the “booster” or “pump” is used to provide additional water heating when the available solar energy is not sufficient enough to meet household demand. As shown in the image above, the booster directly heats the water within the tank before it is sent to the running taps throughout the building. 

While the outcome is generally the same, gas boosted solar hot water systems typically activate at one of two specific instances.

  1. On some installations, a tank temperature is set so that hot water will always be instantly available from a preheated supply.
  2. In others, the gas boost is applied as soon as the hot water tap is activated before being sent to an appliance or tap.

By utilizing a point-of-use gas booster, you are more likely to conserve energy over time. With this, most system owners choose a point-of-use system to save on long-term costs and typically the only real downside is having to wait a few extra seconds for your shower to heat up.

Gas vs. Electric Solar Hot Water Boosts 

If you’ve been exploring the best way to economically and environmentally heat your home’s water supply, then you’ve surely been met with an array of gas or electric boosted options. Both gas and electric power can be used to efficiently supplement a solar hot water system in a home or large property space. 

Below, we will explore the pros and cons of choosing a gas or electric boosted solar hot water system.   

Pros of a Gas Boosted Solar Hot Water System

First and foremost, gas-assisted solar installations are designed for long-term savings. In general, the ongoing operations of most gas-boosted solar hot water systems will be cheaper than their electric counterparts thanks to the fact that natural gas is typically offered at lower rates than electricity from local utilities. 

Environmentally, natural gas boosted systems also produce significantly fewer greenhouse gases than electricity utility fed systems. Of course, this may change globally as more and more clean energy is being produced and sent to the national electric grid. 

Cons of a Gas Boosted Solar Hot Water System

On the other hand, gas boosted solar hot water systems are typically more expensive to purchase and install than electric systems, and thus require higher upfront costs. If you are not using your boost very often, an investment in a gas-fed system may not be necessary.

Beyond this, gas boosted systems generally require more maintenance than electric boosted systems because they have more fluids and additional moving parts. This could add extra costs later, especially if something needs to be replaced or repaired. 

Pros of an Electric Boosted Solar Hot Water System

While gas prices tend to be lower on average than electricity rates nationwide, highly efficient electric boosted solar energy systems may still have lower operational costs than gas boosts with minimal energy use. 

With an electric boosted solar hot water system, it is also possible to incorporate PV solar panels to supply the extra energy needed for your home’s hot water. Although here it is important to consider that poor sunlight conditions will limit overall performance, whereas a gas-boosted system would be able to supply essentially unlimited hot water. 

Cons of an Electric Boosted Solar Hot Water System

With an electric boosted hot water system, it will not take long for you to see a dramatic increase in your electricity bill. If you already own and operate several electric appliances, adding an electric boost may run the risk of consuming enough electricity to be charged at a higher tiered rate from the utility. 

While advanced systems may be able to run for a handful of dollars each month, highly efficient electric boost systems will also require a significant upfront investment. This may cause owners on a budget the need to settle for mid-grade parts and materials, and thus be left consuming more energy and spending more money than expected. 

Verdict: Should I choose a gas or electric solar boost? 

In truth, the choice between a gas or electric boosted solar hot water system is a virtual toss-up that relies heavily on local influences. As both gas and electric boosts have been proven solutions for properties across the country, many cost-benefit analyses of long-term savings between the two have yielded varying results. 

If you are considering a gas-assisted solar hot water system, this will likely be the right choice if natural gas prices are lower than electricity rates or if you already use a significant amount of electricity in your home. This is especially true if you plan to use your boost for multiple months out of the year.

For minimal hot water users with plenty of solar gains, an electric boost system will likely be a better financial choice to save on purchase, installation, and maintenance costs. While natural gas boosted systems are quick to win the environmental vote, it is also important to consider the many sources of green electricity that could help sway electric boosted systems to be considered more sustainable. 

How much does a gas boosted solar hot water system cost?

Alright, let’s talk about some numbers! Although prices will always fluctuate, below, we will explore the costs to consider when planning a solar hot water installation. As hot water typically uses up to 30% of a household’s energy, a gas boosted solar hot water system is a large investment in your home’s ongoing operations.

For this reason, many companies and independent agencies provide hot water and solar financing structures specifically designed to recoup a solar hot water investment. Before moving forward with any product or company, we highly recommend getting multiple quotes from local providers to get the best possible deal, service, and system performance. 

Parts and Installation Costs

First, the most obvious expenses in a solar hot water installation are the parts and labour. There are a few different ways to help minimize upfront costs on your system. Below, you will see a gas boosted solar hot water system with a rooftop tank. This popular system design is often used in place of a standalone tank, which minimizes total materials and installation time in addition to saving property space. 

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When pursuing an installation, homeowners are also given the choice to install a variety of solar collectors both in various size and efficiency capacities. Here, some money can typically be saved by purchasing a flat plate panel or a less-efficient evacuated tube collector that is still capable of getting the job done.  

Ongoing Water Heating Costs 

So although solar energy will remain free until the government figures out a way to tax the sun, there will always be ongoing costs associated with a gas boosted system. Through ongoing use, conservation will always be the key to keeping operational costs low by minimizing the amount of gas-associated expenses.

If your tank can be set to a specific temperature, we recommend knocking it a few degrees lower than what you are used to in order to see a significant amount of savings. Likewise, whenever you head out on vacation, remember to set your heater to “away” mode for minimal costs if possible. 

Maintenance and Future Expenses 

Finally, all good things must come to an end, and even the best gas boosted solar hot water systems will eventually begin to deteriorate. Throughout a system’s lifespan, it is recommended that professional inspection is performed every 5 years during normal use. 

Of course, as the system owner, it is also a good idea to check the system’s valves, moving parts, and performance every year or two to stop serious problems before they happen. Here, you will always be happy to have chosen the system with the longest warranty period in case anything is required to be fixed or replaced. 


Lastly, we’d like to share answers to some of the questions we hear most from Australian home and building owners considering a gas boosted solar hot water system. 

Is solar hot water cheaper than gas?

Yes, a solar hot water system runs on free solar energy, and thus will always be cheaper than any heating system run on exclusively utility-fed natural gas…. to OPERATE. However, solar hot water systems can cost more to initially purchase and install than a gas system.

In this article, we explored gas boosted solar hot water heaters which are able to utilize the benefits of solar energy and make up for its shortcomings with a gas-assisted boost. And such, gas boosted solar hot water heaters can be considered the “best of both worlds.”

What is the most economical hot water heater?

Hot water heater economics are heavily influenced by localized factors such as parts, price, utility rates, and available resources. Across the country, however, solar boosted hot water systems are by far the most economical. 

Behind solar, gas boosted systems are generally more economical than electric boosted systems and there are many proprieties in Australia that are also well suited for other technologies such as heat pumps. 

Do all solar hot water systems have a booster?

Today, nearly every new solar hot water system is installed with a thermostat and booster, though there are many in the wild that run on solar alone. In Australia’s most livable regions, temperature changes throughout the year make a booster entirely necessary for full annual hot water coverage, the choice of which can be gas or electric. 

What is the best brand of gas-boosted solar hot water heater?

In Australia, we are lucky enough to have our pick from a large number of reputable domestic and international solar hot water heater manufacturers. While new companies are debuting advanced models every year, large companies like Rinnai, Rheem, Neopower, and Dux manufacture some of the best gas boosted systems on the market today. 

How does a gas boosted solar hot water system work?

A gas boosted solar hot water system works by automatically transferring the power supply from solar to natural gas when the tank temperature reaches below a predetermined threshold. So typically, homeowners are able to simply set a thermostat and let the system handle the rest of the work. 

With smart hot water usage and good sunlight conditions, many solar hot water systems require very little or entirely no gas boosting for long periods of time. 

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Do solar water heaters work in winter?

Yes, solar hot water heaters work in the winter, although typically at less efficient rates than in summer sunlight and heat conditions. With this in mind, gas or electric boosts are much more commonly used throughout the winter to supplement the power input of a solar hot water system. 

When should I use my solar hot water booster?

Thankfully, many of today’s solar hot water boosters automatically run when necessary, so very little ongoing maintenance is required. When adjusting the settings, most boosters will only activate when the default tank temperature is not being maintained by the energy from the solar panels along. 

Thus, boosters are most often used at night or throughout periods of extended cloud coverage or limited sunlight. Most likely, the booster will only truly be activated when someone in the home is actively using hot water.  

How do I use my solar hot water gas booster? 

To adjust the settings of your solar hot water gas booster, most of the configurations can be set on the installed thermostat. In newer models, it is also becoming more common for smart thermostats to be installed with digital compatibility of controlling your solar hot water gas booster via smartphone or tablet. 

How long do solar hot water heaters last? 

Solar hot water heaters are a simple combination of parts, all of which tend to have different lifespans. In general, most high-quality gas boosted solar hot water installations are warrantied for 15 years or more on the tank, booster, and other main system components. 

With this, most systems can be exposed to last for up to 20 years and more. This is especially true of the solar collectors, which often operate at slowly deteriorating efficiency rates for several decades. 


These days nearly everyone is trying their best to save some money or help conserve the environment, and installing a gas boosted solar hot water system is a great way to kill two birds with one stone (metaphorically speaking of course). 

While there are many different ways to heat a home’s water supply, with the right sunlight and property conditions, it is possible to save a significant amount of money on the long-term costs with a solar gas boosted system.