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Heat Pumps

Learn how to use heat pumps as a battery!

Got Solar? Use Water as a Battery!

Recently Australia reached a milestone of 3-million solar systems installed on homes & businesses. That’s more than 1 in 4 houses!

Unfortunately, for many WA households, a large part of their solar power gets exported to the grid for a measly 2.5c/kWh feed-in tariff. only to later repurchase it from the grid in the evening for 30c/kWh. What a scam!

Not surprisingly, many solar system owners are wondering how they can avoid this…

Shifting electricity usage into the daytime is one strategy we recommend. For example, running the pool pump, washing machine and dishwasher during the day instead of night. But even then, many families still have high night-time electricity usage.

Another solution gaining popularity are Home Energy Storage Batteries. At Positive Energy Solutions more than 1 in 3 of our customers are now purchasing a Battery with their new Solar Panel System. Our most popular options being:

For some customers though, battery prices don’t quite fit the budget. There is, however, a much more affordable way to store some of that excess solar energy…


Heating Costs

A major energy cost for most families (often around 20%) is for heating water. Therefore a smarter, more efficient solution gaining favour is the iStore Hot Water Heat Pump AKA “Thermal Battery” An iStore Heat Pump will use your excess solar power to heat water and store it in a tank for later use. 
Similar to how excess solar power can gets stored in a battery. Hot Water Heat Pumps use similar technology to fridges and air-conditioners. Which use a refrigeration cycle to transfer heat. However, rather than using the cooling effect, a Hot Water Heat Pump works in reverse. (Like a reverse-cycle air-conditioner does when on heating mode)

1. A fan draws in air, containing ambient heat energy, which blows across the evaporator. 

2. The evaporator turns the liquid refrigerant into a gas (CFC Free R134a) 

3. The compressor pressurizes the gas making it very hot. 

4. The hot gas inside the condenser coil (wrapped around the tank) heats the water inside

5. After transferring the heat to the water tank. Then the refrigerant gas turns back into a liquid. Finally returning to the evaporator for the process to start again. 

6. The cycle continues until the water reaches temperature. 

7. The cycle will restart if the water temperature inside the tank drops below 45°C while the water

Heat Pump Economics

The Economics

If you currently have a Gas hot water system, an iStore Heat Pump is a very sensible investment. Especially if your current hot water system has a low star rating or is due for replacement anyway.

Like grid electricity, gas prices are also increasing. Currently, the price of gas in WA is equal to 15.35 cents/kWh.

So, rather than selling your excess solar power to the grid for only 2.5c. You can use that power to heat water cheaper than by using gas. This change boosts the value of your excess solar power by at least 5 times.


270L iStore Running Cost Per Year*

* Savings based on a family of 4 consuming 200 litres per day for one year. Tariffs based on $0.25 per kWh for electricity. Natural Gas price of $0.0351 c/MJ & LPG price of 1.25 $/L. Actual savings may vary on household usage, solar power system and climate conditions.

How much Solar is needed for a Heat Pump?

How much excess solar power do you need?
One common question we get asked is how much excess solar power do we need to run a Hot Water Heat Pump?
The 270L iStore Heat Pump draws 1000W of power and usually runs about 4 hours per day. Or the smaller 180L iStore draws only 500W of power. So, for most typical size homes, the answer is about 2 – 4 kWh per day.
Considering the average solar system size these days is around 6.5kW. Which generates approximately 26kWh per day on average. There is usually plenty of excess solar power available for the iStore Heat Pump.
Our Advice: Instead of paying around $500 per year for gas to heat water. Use your excess solar power instead which Synergy values at only $30 per year. Interested in the iStore Heat Pump? 
Request a Quote today and receive up to $1,000 STC Discount

Solar and Battery Upgrade | Port Kennedy

We recently upgraded & expanded a system for our customer in Port Kennedy with 4.5kW of extra solar panels, new Fronius Hybrid inverter and 11kWh BYD Battery.


Solar and Battery Upgrade | Secret Harbour

We recently expanded & upgraded an existing system in Secret Harbour with an extra 9kW of solar panels + new 10kW Sungrow Hybrid inverter + 12.8kWh Sungrow Battery.

Contact Us

Give us a call today and one of our friendly and knowledgeable energy consultants will be able to assist you with your enquiry.


Level 1, 59 Howe Street Osborne Park, Perth 6017


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