Why Solar Hot Water Systems Are, Fortunately, a Waste of Money

For an unknown reason solar hot water systems have grown to become nearly as popular, if not more so than their larger and more powerful cousins, PV solar systems. Most likely because they were the first kids on the block and gained popularity as the more stable option during a time when Solar PV was not yet efficient enough to capture public attention. Today, they are just a little bit silly.

Firstly, to get over any confusion, solar PV and solar hot water systems usually refer to two entirely different technologies. Solar PV is short for solar photovoltaics, meaning any technology which uses light to directly generate electricity. Solar hot water systems make use of solar thermal technology, meaning they rely on the Sun's heat to warm running water, usually by exposing an array of pipes to the light directly.

The shocking thing is, while you can buy a Solar PV system for $5000 - $7000 on average, the cost of a system that is only capable of heating your hot water will put you back a couple of thousand dollars. Worse than this, many families choose to purchase a hot water system without considering a Solar PV system, or opt to fork out nearly $10,000 to get both.

Interestingly, studies show that the most effective way to heat your hot water is by simply hooking up your existing solar system to your hot water tank. One solar system is entirely capable of powering both your home and your hot water. But, don’t take our word for it, a study from 2014 proved that solar PV was the least expensive method for heating your hot water.

Essentially the study showed that overall, solar PV can save you an additional $2000 when used in combination with energy storage, and is extremely competitive without storage. Given that using solar PV saves you having to spend additional thousands upfront, the fact PV is also more efficient to use is an added bonus.

The solar hot water industry was in 2009 actually larger than Solar PV, yet as solar cells improve and the demand for independent solar hot water falls the industry has taken a heavy hit over the past 7 years. Solar hot water shipped 200,000 units in 2009, which is meteoric when considering that only ~60,000 units were shipped in 2013. In comparison, solar hit a high of 360,000 units in 2011 and only falling to 200,000 in later years.

Ecoelectric managing director Jeff Wehl ,the company which conducted the study, had this to say:

“With over a million homes in Australia already having solar panels on their roofs, many people are unaware that these panels can be used to realise greater energy efficiency and savings, via the heating of water for their home.”

The great thing is that many people who thought they missed out on a solar hot water system, can spend a couple of hundred dollars and get the same results with a hot water timer.

There are a huge number of benefits that come with installing a hot water timer over a hot water system, beyond efficiency and cost. For instance, a timer requires much less space, and lesser components, making the installation process less of a headache.

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Solar thermal technologies are incredibly fragile, they must be pressure tested, and use heat transfer fluid to make sure that enough energy is captured and properly sent to the tank. However, if something goes wrong, it goes horribly wrong. As soon as fluid stops moving, the pipes begin to freeze and the whole thing becomes unusable. Where as solar PV hot water timers suffer none of these issues, making for a better customer experience overall.

It is a wonder why we still see solar hot water systems being advertised and sold separately from solar PV or worse solar together as two independent systems. Maybe it is because most consumers don’t know how efficient solar cells have become in recent years, or because the solar hot water industry refuses to go away or at least adapt to a better system.

All in all, unless you bought a hot water system when the only alternative was gas, or were mistaken and bought one not too long ago, this should be a nice surprise for many solar PV owners.

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