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Quantum Energy AC4 Series

Quantum Energy AC4 Series (page 2 of 3)

Compact 150L, Compact 200L, Compact 270L, Compact 340L and Titan Compact 340L
2.6 from 52 reviews

great unit.....would support any progressive technologies

Wouldn't go back to gas storage, instant gas or elemental electric
This thing produces endless hot water for my medium size family
12 months on and hasn't disappointed us yet

Glorious hot water

We purchased a house in far east Gippsland not long ago. After settlement, we soon found that the electric hot water service was leaking. After some time on the internet researching replacement environmental friendly options, we came across Quantum Energy Technologies great offer. In this, they supply and install your new heater then claim the rebates currently available from the Federal and Victorian governments. All you pay is a small amount direct to Quantum. Such a good offer that we purchased a second unit for our Melbourne address.

This action was in the first few days of January during the Christmas break,and yes you can probably guess what happened next. We turned on the old unit on arrival on a Sunday night and anticipated hot water the following morning. Instead we were greeted by water flowing down the drive from the failure of the pressure vessel.

Katie prioritised our installation following the failure of the old unit and our new service arrived from Sydney in a few days. Then Quantum's installer arrived a little later after to connect the new heater.

So well done and thank-you to the Quantum team. Great customer service! We are very pleased with our choice.

It is early days with the unit, and it will be a little while before we receive an electricity account, but I can confirm that the unit is very quiet and below the level we expected.

Paul Cribb


just out of warranty and you guessed it leaking water from the tank,
I have installed at least 20 plus quantum hot water units within the last 6 years and have a failure rate of in excess 25%, NOT HAPPY JAN I would have a drama installing another quantum sad but true.

1 comment
another 2 units have failed within the last month, this product is absolute rubbish and by my best interests I reckon cheap overseas rubbish and not made to last, some one made a fortune on these and it was no way the purchaser as we got robbed . total failure rate now at least 50% ++++

Quantum Heat Pump Under 3 Years Life

Quantum heat pump split after nearly 3 years. Quantum sold me a new one for 1400.00 delivered but still! They also get to keep the rebates. Cost of plumbing, electrician, etc. makes for a pretty expensive heater.

Steer clear

Purchased 340litre quantum HWC through Orange Tehnologies NZ In July 2014 and it went fine for a few months. Now we are having to turn it off regularly as the neghbourhood has had enough of the extreme noise. We regularly have no hot water and no technician or Quantum knows how to fix it and they are SLOWLY replacing parts with no good results at our inconvience. Eg Friday Quantum Australia agree on another part and it doesn't get installed by technician until the Wednesday/Thursday Another week with hassles. All Warrantee claims have to go through Australia so can't be sorted till they give the OK. This can take days especially if it is a Friday. We are so over it and are hoping the out come come will end in cash back and then we can choose anything but a Quantum. The only reason we chose this one is that we had 1 for 17 years any only had a few problems with gas leakage which was an easy fix. New model doesn't live up to the test. We have asked them to replace it in case this one is a lemon but they seem to want to keep just trying to repair without any success.

No problems here.

We installed a Quantum system (Heatpump hot water) in 1993 when we built our present home. As it's an old one you cannot get the gas (R21?) for it now but it's cheap and trouble free. Ours lives in the corner of the garage and makes little or no noise. This model has collectors on the roof through which the gas flows and exchanges the atmospheres heat. It seems to work best when it's raining or blowing and uses 500W. $20 a month for hot water....

Fantastic - Quantum hot water system

Hi, we've had our Quantum 340L heat pump installed for about 5 months now. We live in the Adelaide Hills and run the system using off-peak electricity. It has worked perfectly even during the cooler nights. Compared to our old element system (also used off-peak) we now only use about 20% of the energy. Our annual electricity saving is $650 pa (daily cost to heat water is 40c vs $2 per day). I was concerned regarding the noise from the other reviews but they aren't very noisy. We have ours located outside the kitchen windows and have trouble hearing it from inside the house. Fantastic. If you are looking for a reliable installer in Adelaide we used SA Hot Water and they were superb.

Cheap efficient water heater

We have had our 250ltr quantum heat pump for 9years...replaced small white cylindrical solenoid 3 years ago but no other issues. It runs for 2-3 hours like an inverter aircond so don't place unit near bedrooms. Our electricity bills are very low with this system on off peak1...wont heat up enough on off peak 2 as we discovered. Would highly recommend this system

Heat pump died after 5.5 years

My quantum heat pump compact 340 has rusted out after 5. 5 years I swaped it from a twin element 400 litre electric heater when the rebates were on but it has not lasted it has a roof over it specially made to protect heater from the elements but it still rusted out , will see what quantum has to say on Monday when I ring them to complain as I am a plumber that has installed a load of these heaters and now my has rusted out I am waiting for my customers to starting ring me that there's has crap it self as well as my was the first that I installed after doing my research on heat pumps

Thank you Quantum Energy!

Just updating my experience with expensive and ineffectual repairs to our Quantum Energy Heat Pump (reviewed April 18). Thanks to Quantum's intervention, their service agent yesterday refunded the amount charged, less the call out fee which we agreed to pay.
After four weeks with no hot water we are now able to purchase another hot water system.

Good Product - Very Efficient

Our Quantum has just died after approx 20 years of use. Very cheap hot water. It was in the garage and we had no problem with noise or rust. We are going to replace this with the smaller 200L unit as we don't need the bigger size.

compressor lasted 14yrs tank still going

Noisy yes but used little electricity and compressor ran for 14 yrs. About what you'd expec from a fridge or similar. Hoped for more but pretty happy.

Stress purchase of a Quantum 270, by a high priced installer

We have just had a Quantum 270 installed due to the failure of a 15 Year twin element off peak. Fell for the Omega sales pitch regarding 75% electricity savings, and paid the ridiculous price of $6400 installed. Then encountered all sort of issues with our Energy Provider in switching to the suggested Off Peak 2 from 1. The provider employees knew little about the difference in Off Peak numbers. Then we received an energy offer which only had three hurdle rates for Peak, albeit at half the normal Peak rate. All up very wary, especially as the warranty of 6 years is still less than other brand units at half the price. Did receive good communications from Quantum when chasing comparison details and the STC rebate of almost $900. Yes the unit is noisy, but at this stage not annoyingly so.

Noisy & Unreliable - avoid!!!

Unfortunately installed these units six years ago and put up with the noise throughout that time. Neighbour thought we must have a very clean house as she thought we were using the ducted vacuum all the time! May have been more energy efficient, but having to switch from off peak to peak power meant they were no cheaper. Broke down after warranty and thankfully only $300 repair. Lived with these units until we sold the house and moved. Have nothing good to say about these units. Never again.

Noisy water heating

From the first day we moved in, I was aghast at our new water heater roaring away outside our bedroom for hours every night. The only positive thing:yes, it produced hot water. Advice: note the past tense and steer clear.

Very happy

I have had 2 270ltr units installed on my home and besides a malfunction with the computer on one unit, (which was covered by warranty) I couldn't be happier with the quantum heat pumps. It provides hot water to my taps faster than any other unit we looked at and with the temp set its never scolding hot. Thumbs up from WA :)

Quantum Heat Pump now out the dump!

I have just returned from taking my 6 year old Quantum 250L heat pump to the dump. I have replaced it with a bog standard electric hot water heater and couldn't be happier. It will be only slightly more expensive to run than the heat pump once I switch it to off peak (controlled load 1).

These heat pumps are touted to be cheaper and better for the environment. But they aren't that much cheaper to run. Cheaper for me is calculated by original cost price, minus running costs, minus repairs. This heat pump was rusting out, we had to pay for a off peak meter board switch to reduce running costs, and now it's died and no a/c tech in our area will touch it.

As for the environment, what about the cost to the environment of making it then having to recycle/destroy it only a few years later?

These heat pumps are basically small, noisy air conditioners. They run for 3-6hrs per day, every day. That's about 1000-2000hrs a year. With so many moving parts, gas joins and electircal wiring out in the Australian elements it's no wonder they aren't lasting long.

I join with the host of other consumers who sadly but with a sense of relief, farewell the failed, flawed and finished heat pump.

It was with the house when we bought it.
Noisy, rusted, failed and was not repairable.

Do NOT buy a heat pump -Too Noisy

The Quantum heat pump is extremely, extremely noisy. We now have to spend $4,000 on a gas system because the Quantum system wakes our young family and neighbours up. I do not why ethically Quantum can sell them without disclosing how much noise pollution they provide. I urge anyone to avoid considering a Quantum heat pump.

too noisy

Hi Roger, they should be no noisier than the outdoor unit of a Split System Air Conditioner, which has been my experience with them. Perhaps you have a faulty bearing in the fan or something else that needs maintenance?Hi Roger, the Quantum's are the quietest on the market (depending on the model). there is also a baffle that can be used to further reduce noise. if it's as noisy as you state there may be some issue with the fan - if it's new warranty may cover itI have a very noisy Quantam heat pump and the company employee came out and said that the noise level is loud because it is between two buildings and said that there is nothing wrong with the unit. Also the plumber Quantam sent out did not install it correctly so I had to pay another plumber to move it onto a concrete slab and drain the considerable water away to a more suitable location. (The technician did not comment on the installation I noticed it after reading the manual and then a further two installation problems were detected by someone else ( I have taken photos)) My son is having a breakdown so now we are forced to spend more money to have an electrician put a timer on it so he can get some sleep but it will be unbearably noisy during the afternoon. What a waste of money........

Quantum has been fantastic

Although this quantum unit was purchased 14 years ago, we have never had a problem with it producing instant hot water.
It has produced bountiful steaming hot water and halved our energy expenses.
I got it serviced two years ago as recommended by Quantum although it didn't seem necessary as it was functioning

Seemed expensive at the time but pretty cheap in retrospect !

Inexpensive Hot Water

We have had a Qantum Hot Water System for 6 years now, and it is still going strong. We regularly get down to overnight temperatures of minus 5 degrees, but we also have plenty of hot water, so the sub zero air temperatures don't bother these Heaters. Quiet, efficient , and helps keep the electricity bills low. Cannot really comment on Customer Service as we haven't had any problems.
Inexpensive Hot Water
The fan can sometimes be a bit noisy, so avoid putting one near a bedroom.

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Questions & Answers

why is the water in the system hot. but not hot coming out not even luke warm
No answers

I hear a loud buzzing every 10-15 minutes. What would cause this?
No answers

Hi, my late father had one of these units put in in 2013. My mum is concerned that the unit seems to be running for longer than usual lately. I've just started taking an interest in it, after a 5 minute shower it seems to run for around 4 hrs. We are in nz and the climate is cooling down after summer, but can anyone tell me what an average run time is? Our unit is a 340-11AC4-134. My elderly mum is concerned the thing will get too hot and burn the place down! Our unit doesn't seem to have the red alert indicator on the outside, so I guess I have to take the cover off the top of the cylinder and see if the control box is showing any error codes. Any advice appreciated, thanks, Jeff
No answers

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