Komo Energy

Owner occupiers in Victoria have a current opportunity for 2 or possibly 3 rebates for efficient hot water at the moment. And modern-day hot water heat pumps are a transformative way to reduce energy costs and support renewable energy. This article explains why, and some links at the bottom to help you get one ASAP.

Typically Hot Water Heat Pumps cost $5,500 for heat pump and tank. But with Renewable Energy Certificates and the new Solar Victoria rebate, you can now get them for $3,400. Maybe even less if eligible for Victorian Energy Efficiency Certificates.

They really are an easy and cost-effective way you can take action at home to help the transition to renewable energy.

Hot Water Heat Pumps are very efficient and reduce energy costs

For some households, hot water heating can be 50% of your electricity use. I know this, because this was the case for us prior to switching to heat pump.

Typically heating hot water each day for our hot water tanks using electric hot water (resistive element) requires 8kWh per day. Alternatively, gas hot water systems use 36 MJ per day. Hot water heat pumps are efficient, and only use 2kWh per day.

Picture: Sanden Heat Pump & Tank (Source: Sunny Shire)

The savings depends on a few things. Electricity for electric hot water can cost 14-18 c/kWh for off-peak controlled load, or 24-30 c/kWh for normal tariffs. At 8 kWh per day, this means annual electricity costs can be $410 to $910 or more annually.

Reducing consumption for hot water to 2kWh per day can reduce this to $100 to $220 per year, savings $310 to $680 per annum.

Gas has also become expensive in recent times, so similar savings are possible. Better yet, it can be part of switching away from gas altogether and eliminating that bill.

They are actually another form of renewable energy

 Heat pumps can produce 8kWh equivalent of hot water energy using 2kWh of electricity. This gives it a Coefficiency of performance (COP) of 4.0, or efficiency of 400%. It is not magic, but it does sound like it!

 Heat pumps use a refrigerant loop much like refrigerator to draw thermal energy from the ambient air outside to heat the hot water. This is shown diagrammatically below:

Refridgerators pull heat out of the inside of the fridge and put it outside the fridge. Hot Water Heat Pumps draw heat from outside air and put it in the hot water tank. A good heat pump, like the Sanden Eco, can do this down to -10 degrees. Even at sub-zero temperatures, there is enough energy in the air for the heat pump to work.

Of course, our outside air is warmed by the sun. So as the heat pump draws this energy, it is another form of renewable solar power. This is why Heat Pumps create STC Renewable Energy Certificates like rooftop solar does, providing an upfront rebate of $1,000 for heat pumps. 

They can provide a new ‘baseload’ for solar power

Heat pumps and solar PV go perfectly together. Heat Pumps draw 1kW for 2 hours each day, and can be set to turn on each day during solar hours to utilise your rooftop solar.

Here is an image of our heat pump operating from 11am to 1pm (in blue) and being powered by solar (Green & Blue).

But this also applies to the grid more broadly. We are getting more and more solar in our grid, through distributed rooftop solar and solar farms. One thing that may hold up this investment is we generate so much solar, that it becomes abundant so less valued. For solar farm investors in particular, this can mean reduced revenues. For grid operators, they have to manage this excess power. This is already happening in South Australia where solar can meet over 50% of middle of the day demand, sending wholesale prices negative.

Currently much of Victoria’s hot water is heated overnight to create ‘baseload’ for its brown coal power stations. For Victoria’s 2.2 million homes, if we switched them all from gas hot water and overnight electric power, we could create a new baseload for solar of 2,200 MW every day for 2 hours. As we use the hot water through the day overnight, it is a form of storage. 2.2 million homes with hot water heat pumps and tank would be the equivalent of a 8,800 MWh battery, equivalent of 67 SA Tesla Big Batteries.

Victoria current generates 1,100 MW from rooftop solar and is reaching 150MW from solar farms so far, with 800MW confirmed and on the way. Adoption of hot water heat pumps and use during the middle of the day could help support much more.

This change would drive more investment in solar, allow grid operators to manage this increase solar and reduce support of the brown coal power stations.

For our southern states, they are superior to Rooftop Solar Hot Water

You may be more familiar with rooftop solar hot water. In our southern states, such systems tend to over produce in summer, and under produce in winter requiring top up electricity from the grid. But using now power in summer and lots in winter, this is the opposite of supporting greater solar adoption, it works against it.

In more tropical climates, rooftop solar hot water is fine with more consistent heat across the year.

With heat pumps using 2kWh per day, this is the equivalent of 2 solar panels across the year, so can easily be offset at home. Rooftop hot water also takes up space where rooftop solar PV could go, and rooftop solar PV is more flexible and useful and can power your heat pump plus other appliances in your house.

Where you can get them

Sanden ECO is the best, as it is the most efficient, quietest and comes with best warranties.

It is easy to get one. With many reputable suppliers that can arrange supply and installation and help you with any advice and assistance accessing the rebates. Here are some:

·     In Northern Melbourne or Castlemaine region, contact Enviroshop: http://enviroshop.com.au/home/efficient-hot-water/

·     Elsewhere in Victoria, contact Pure Electric: https://pure-electric.com.au/products/sanden-eco-plus

Why not email or call them now?

Another option that also has a social benefit is Earthwoker Cooperative which is a workers owned Coop manufacturing hot water tanks in Gippsland, and these are around $1,000 cheaper; https://earthworkercooperative.com.au/bolt-on-solar-heat-pump-tank-package-315l-tank/

Of course, hot water heat pumps are great in NSW, South Australia Tasmania too, and in Sutherland Shire our community energy group has a bulk buy for Sanden Heat Pumps: http://sunnyshire.org.au/hot-water-heat-pump-bulk-buy/

(I have no financial interest in Sanden or the above suppliers)