Heating Water With Solar Immersion Diverters No Longer Make Sense
If you want to heat your water using free energy from Solar PV panels then it's time to look at a different solution
What is a solar immersion diverter?
An immersion diverter, also known as an immersion optimiser, is a water heating module that when added to your solar PV system, uses excess energy generated to heat your water cylinder rather than sending it back to the grid. In the past this was very handy, and a very smart use of the energy you generate. But now with smart tariffs and the Microgeneration Scheme is it still needed?
Eddi & iBoost Immersion Diverters
A Smarter Way To Heat Your Water
Before smart meters were introduced in 2021/22 homeowners gave away the excess electricity generated by their solar PV panels to the grid for free. So an immersion diverter was a smart investment. Instead of giving electricity away, you could turn the excess energy generated by your solar panels into hot water.
However nowadays with the Microgeneration Scheme you get paid by your energy supplier for any excess electricity you send back to the grid. And with an optional battery storage add-on, you will significantly improve your consumption of the solar energy that is generated.
It’s now much more financially beneficial (and environmentally friendly) to store energy in your battery for consumption. And when your battery is full, sell the excess electricity back to the grid. But if you need to buy additional electricity to top up your battery, you can do so at a low night rate. This guarantees you power your home with the free solar energy you generate. And with the correct smart meter tariff and timings, you can heat your water very effectively — dramatically reducing your energy bills.
Big Solar Energy: Buy Low, Sell High
Many smart meter plans allow you to buy back electricity at a much lower rate in the middle of the night. For example, as of November 2024, with Energia you can sell any excess electricity to the grid in the day for 24 cents per unit and then buy it back in the middle of the night for 8 cents per unit. For every unit you give them, they’ll give you three back in the middle of the night!
If your primary goal with solar is to generate hot water, it’s generally more cost-effective to sell the electricity you produce and set a timer to turn the immersion on during off peak tariffs to take advantage of night rate energy (three hours for the price of one!). Or set it to come on daily during peak sunshine hours only (i.e 11.30am to 1.30pm) when it’s most likely that the solar system is producing energy optimally.
Go With The Flow (Of Energy)
You are planning to install solar system with a battery therefore the energy flow is as follows:
You will note that a diverter is last to be powered but the battery will have received a full charge because of this we cannot guarantee that the water will be heated on a consistent basis from a solar water diverter, particularly during the winter.
In summary, through our experience we find the optimal way to heat water, particularly if your immersion is the primary source for hot water, is to fit a time switch to use night rate or battery stored energy. This will ensure that you have hot water when required. For more information on immersion diverters or to discuss your own bespoke solar PV system, contact Energlaze today for a free consultation and quote.
