Is a Solar Water Heater Worth It?

13 / 03 / 2019

Water heating is the second biggest household energy user (just after space heating and cooling). Approximately 25 per cent of the household energy use is due to hot water (for bathroom, laundry and kitchen use).

Because of the sizable operating expenses (and the increasing utility bills), it’s really worth it to pay attention to the water heater you’ll use. Keep in mind that this will be an ongoing expense day in and day out. You have to consider how much your monthly expenses will be and the upfront price of the water heater itself.

Is a solar water heater worth it?

As a result, many consider buying a solar water heater mainly because of the free energy source. You don’t have to pay each month for the electricity or fuel. You also support green energy and environmental protection with the use of solar-enabled technologies.

But as with most things (especially things that we use or consume every day), we often consider both the upfront and long-term costs before making a purchase. Is a solar water heater (SWH) too expensive and will it be worth it in the long run? Do you actually save money in contrast to choosing a gas or electric hot water?

First, an SWH can only provide 50 to 90 per cent of your hot water needs. Often you need gas-boosted or electricity-boosted SWH so that you can get enough hot water for bathroom, laundry and kitchen use. That’s because solar cells and panels are not that highly efficient when converting sunlight’s energy into useful energy to heat the water. The mentioned percentages depend on your location and direction of solar panels (i.e. abundance of sunshine) and the amount of water you use (if you have a big household a 100% solar water heater is not enough).

In other words, getting the most out of the solar water heater depends on the following:

  • Your family size
  • Climate (e.g. abundance of sunshine, dominating weather in the area)
  • House type
  • Roof characteristics
  • Water quality
  • Available space (both the solar panels and storage tank require significant space, the wider the space available, larger or more solar panels can be installed)

As mentioned earlier, the direction of solar collectors is also important. For instance here in Australia, the solar collectors should be facing as close to north as possible to maximise efficiency. This is easy to achieve if the roof type and house orientation allows for such optimal installation. What about other directions? Installing the solar collectors facing east or west is still good but the amount of energy to be collected will be significantly lower.

You can already notice here that the manner of installation could be as crucial as the SWH itself. And getting the most out of the unit could largely depend on how the SWH is installed and other factors such as climate and location.

When it comes to climate and location, do you live in a frost-exposed area? Canberra, Melbourne and areas near Sydney can be exposed to frost and temperatures below 4℃. Frost can affect the SWH’s performance and efficiency through heat loss (cold temperatures outside can draw out the heat) and damage to the solar collectors (water inside freezes or there’s moisture build-up inside the collectors).

Water heater specialists solve this by including these frost protection measures:

  • Frost protection valves (relieves pressure and encourages water circulation)
  • Antifreeze (most common solution in heavy frost areas or sites with many days of frost)
  • Circulation pump (uses extra energy to warm water through the pipes)
  • System draining (drains the water in the collectors when freezing starts to become a risk)

Aside from climate, location and manner of installation, water quality also affects the SWH’s performance and efficiency. Water with high amounts of dissolved minerals and sediments can result to corrosion or mineral build-up in the storage tank. This can also lead to blocked pipes, failed valves and lower heat transfer. Water heater specialists have technical solutions for these scenarios.

Licensed professionals should install the solar hot water systems because of the complexity and variety in installation scenarios. As mentioned earlier, making sure that the solar water heater is worth it could depend heavily on the manner of installation (which then in turn depends on the expertise of installers). It’s not a one-size fits all wherein you only buy the best SWH and then move on no matter what climate or water quality you have in your area. Instead, it’s also about accounting for the unique requirements your household and site have so that customised and optimal solutions will be given.

Here at NSW Hot Water Pty Ltd we thoroughly study your unique requirements and that of the site so that we can customise the installation for you. This is important so that you can realise long-term savings from the use of solar water heater. Contact us today to ensure optimal installation and 100% compliance to the Australian Standards.