Energy Accounts and Billing

Help with your AGL Energy account or AGL online tools.

Help with your AGL Energy account or AGL online tools.

Hot Water Gas Meter ITRON UltraMaXX HW recording higher usage


Hi All,

In Feb 2018 Jemena has installed new gas hot water meter for my unit. I live in building with 24 blocks and I am the only person having that meter. Since this meter been installed I am getting very higher usage bill, roughly almost $400 approx for 90 days. We are only 3 person and hardly use hot water just for shower.


I strongly believe its because of wrong billing which AGL doing. Here is my meter pics with read.


They are using all digits from reading, multiplying by 10, then further multiplying by conversion factor .32. So if my meter reading shows 79.375, they are capturing this bill without decimal 7937.50*10*.32 like this and showing total usage 25400 Usage MJ. And this figure get further multiplying by usage and supply charge @0.029 and giving $736 which I believe is very high.


Question or Doubt what I have -

1) When my meter reading showing only five digit usage 2 integer digit and 3 decimal digit e.g. 79.375 , refer the link above then why AGL showing that figure in their bill like this 7937.50. Changing from 5 digit to 6 digit and moving decimal position.


2) How do I know whether my meter recording water liter in KiloLiter or just Liter? what this 79.375 number represent. I mean measurement Unit? It shows at the end of number cubic meter? What cubic meter represent and how it should calculated for billing?


3) The usage on meter. Is it water usage or gas usage? what exactly it is as the purpose of this meter is to measure Hot water usage running through GAS.


4) If possible share the details how Digital meter reading should capture and calculated. I already got one link where they are showing how you should read Digital Gas Meter reading but I am more interested how calculation should run.






thanks Nam - I have been in contact with your team, and they have unfortunately not been able to help.  I am being lead to believe that I consume 177MJ of gas a day - for a 2 br apartment with only gas hot water and cooktop, that is monumental.  It seems many others have the same issue, but no one is able to explain how this could happen, and what could cause it.


Hi All,


I am having exactly same issue and sort of figured out the reading issue that AGL has for Cyclonic Meter Read VS Digital Meter Read.


I strongly believe that Digital Meter read should be read as it is shown in the meter


This should be read 15.59 so the reading is consistent with the cyclonic dial.


Based on the decimal read


-The cyclonic dial has 4 digits after (wxyz)

-whereas the Digital Meter only has 3 digits (xyz)


When 10 litre hot water is used - the cyclonic dial x turned into 100 however  the digital meter y turned into 10!!


After much research, i figured that's how the Itron UltraMaxx users are scammed by AGL.. 10x the Bill..


I did a lot of research on this and have added this to the site - hopefully, it helps others.  The main message is to keep monitoring your hot water usage!  You have lots of info to help you do this, that you might not be aware of.  Have a look at the "Readings" section below for what I did to track usage


If you have a gas cooktop and gas hot water, you will have at least two meters in your apartment.  One will be in the kitchen somewhere near your stove, the other probably under your laundry sink.  The one in the kitchen is for your cooktop, and generally should normally register around 1,500 MJ for a two - three person household.  Any higher than this, then you might think of having it checked.


The meter under the laundry sink is your hot water meter, and this measures the number of litres of hot water that you consume.  If you have high gas bills, it will almost certainly be this meter that is causing the high costs.


Because the highest proportion of your gas bill is due to hot water usage, this post focuses solely on how to check how much gas you are using that is attributable to hot water.


Common hot water systems

A “Common” or “Centralised” hot water service is just that – a single system that heats water for all apartments in your complex.  Somewhere in your building, there will be a gas fired boiler which centrally heats the water and distributes it through the pipes into each apartment. 


Because the water is heated centrally, if you find you have increased gas bills, this creates a number of issues:


  • there is no way for you to check what your gas usage is or the costs of heating the water you use as there is no gas meter in your apartment
  • there may be an issue with the boiler, and you probably dont have access to check it
  • the boiler should be serviced regularly, and if not, then it may operate inefficiently, causing higher gas usage
  • if your apartment is some distance from the boiler, you may have to wait a long time for your water to run hot, which causes increased HW usage
  • if the occupancy rate in your apartment complex is low, then the same amount of hot water is heated but the cost is distributed across fewer people, which means your bill is higher
  • the boiler may be set to a high temperate to cater for all users, whereas, it is more energy efficient to set water temperature at 40 - 45° (rather than add cold water to very hot water). 


There are ways to work around some of these issues.  Here are a couple of quick and easy ways to do so.


Start with the boiler


Speak with your building manager and check if:


  • occupancy rates are low (or have been over the last year or so)
  • whether the boiler has been recently serviced
  • whether there are any leaks evident in the boiler room, or elsewhere in the complex
  • what temperature the boiler is set at and see if it could be adjusted.


If the building manager is not overly helpful, then just ask your neighbours if they have high gas bills – if the issue is the boiler, everyone will be getting high bills.  It might be easier to get the manager’s attention if everyone has the same issue.


Check your hot water meter


Allocation of usage to your apartment


Before we explain this, you need to know a little bit about how the gas wholesaler (Jemena) and your retailer determines the gas used by your apartment to heat your hot water. 


As we said above, the water in common hot water heaters is centrally heated, so you don’t know your own personal gas usage.  To get around that, Jemena, (the gas wholesaler which supplies the gas to your retailer), measures the amount of hot water used by each apartment in your block to work out your relative proportion of usage.  They do this by installing a hot water meter in your apartment – this is the one under your laundry sink.  Then, they take a reading of everyone’s hot water usage, and just proportionally allocate the gas used to heat the boiler.  Your retailer then takes that information and applies the billing rates according to your gas plan, and works out how much your bill is.


What your meter measures


A digital meter (such as the Itron ultramaxx) reads the amount of hot water that you use in your apartment in cubic metres, which is 1,000 litres.   You'll see that there is a decimal point showing before the last 3 digits, so if you ignore the decimal point, it's actually telling you the number of litres of hot water that you've used.  


This is pretty handy because you can do a number of things to check if it’s reading correctly, without having to pay Jemena to do it.


Tips to measure accuracy of your meter


Has the meter been properly installed?


Firstly, you should check if only hot water is passing through the meter - you can easily do this by turning off the stop **bleep** before the meter and then alternately turning on your hot and cold taps at the basin - the cold water should flow and the hot water should not - if that happens, then you know only the hot water is passing through the meter.


Is your meter reading correctly?


By filling up a bucket from one of your hot water taps, you can check your meterage by comparing the volume of hot water you have put into the bucket to the change in your meter.  If you fill a standard 9 litre bucket, the last digit on the meter should move by 9 units - if it does, then your meter is reading the amount of hot water you are using accurately. 


There are other types of meters, and I dont have experience of those, but I am sure there will be ways to conduct a similar test on those meters.


By the way, the digital display screen on the meter will probably be blank.  It's not broken, just in power saving mode - press the red button and it will activate the LED reading.  




By far & away the most important and valuable tool to check your usage is readings.  It’s important to look at usage rather than cost, because that takes the possible impact of price changes in undertaking your analysis. 


Before we look at how to measure usage, you need to understand what your meter measures, and what your bill measures. 


Retailers generally report your usage in decilitres on the bill, but the numbers on your meter are in in cubic metres (m3, or 1,000 litres).  If you ignore the decimal point on the meter, you get the litres used. 


Details of your hot water consumed are also shown on your gas bill. For AGL bills (and possibly others), the opening and closing reading is displayed in the bill detail.  This is the total number of decilitres that you had used on that meter at the start of the period and the total number of decilitres you had used at the end of the period.  The hot water you used during the quarter is the number shown under the heading "Units", and is also in decilitres (it’s just the difference between the opening and closing readings). 


Because your bill is in decilitres, your retailer multiplies the number of units shown on your bill by 10 to convert to the number of litres consumed.  This is not a scam, as many have insisted


With that background, here’s what I did to check my gas usage:


  • Measure your hot water usage as often as possible - take a photo of the meter every day at around the same time. 
  • Note the usage each day, including the reading, time and date, and see what your usage rates are and do a daily average (if you miss a day or two, just average it out so you can see if it’s around your expected daily use).  I did a simple excel spreadsheet to help out.
  • After a couple of weeks, you'll be able to see how consistent your usage is, what factors influence it, what your average daily usage is, and whether it is within the parameters that you would expect (these are below).  
  • You can also see if there are changes in your daily usage - mine was pretty much 200 litres a day with 2 or 3 people. 
  • Check this to the usage on your bill – as I said above, your bill has the details of your two meters – the hot water readings in the detailed analysis on the second page which should correlate to your “WT” meter – check the reading on your last bill and see if it aligns to the current reading.


  • You can extrapolate the average daily usage for the quarter (just multiply by 90 days to get the expected quarterly usage) and check this to your next bill, or your last one


  • Check the water usage on your last bill - does it align with your extrapolated daily reading?  


  • For any significant variances between the days, you need to consider what you did during the previous day to see what has influenced the spike in usage – cleaning bathrooms & showers, having a bath, using hot water in your washing machine, etc.


  • Have a look at your hot water usage according to the last 6 or 7 bills and compare bills issued in comparable months (eg compare the decilitre meter readings in Sept 2020 to Sept 2019, etc) - this will give you usage in the seasons - hot water is usually higher in winter.  You can get all of your bills online, so this is much easier and quicker to do than it sounds. 


  • What I found was that, according to my bill, my meter was replaced in May 2019, and usage changed substantially.  Check if your meter has been replaced, and if so, whether there is a change in the usage based on seasonal billings.


The above might sound a bit time consuming, but it was a simple way to keep tabs on usage and provide meaningful feedback to the gas retailer.  Once I had the system set up, and realised what I needed to do, it was really easy, and only took a minute or so a day.  I can certainly say that, compared to the amount of time wasted speaking with the “customer assistance” call centre, it was time well spent. 


Here is a summary of what I came across. 


  • Before I contacted my retailer, hot water usage was on average 313.4 litres per day.  The readings showed precisely the same average daily usage, which seems odd. 


  • After I registered a complaint that the meter was wrong, overnight, with no change in activities or use, average usage fell to 200 litres a day.  Maybe that’s a coincidence, but it is passing strange that such a dramatic reduction occurred immediately after I complained about the meter.


  • About 18 months ago, my gas bills skyrocketed.  When I looked at the readings for hot water usage in one of my old accounts, it showed that a new (Itron Ultramaxx) meter had been installed.  When I compared the readings pre and post the new meter, the usage apparently doubled, but there was no change to usage, appliances, or number of occupants. 


  • I also took readings last thing at night and first thing in the morning – one night, 10 litres of water had apparently been used, and another showed 4 litres being used.  No one had used the hot water at all – everyone was in bed asleep.


  • After three weeks of monitoring, I found my average usage was 200 litres of hot water a day.  Then, inexplicably, 460 litres was used overnight. 


All of that told me that there was clearly an intermittent issue with the meter.  The matter is now before EWON, and they are getting the retailer to try to make sense of this.  I am asking for half of my bills to be refunded.


How much hot water can I expect to use?


SA Water usage estimator


To be able to estimate your usage, there's a handy reference at SA Water - here is a link:  


Estimated hot water usage rates per person


I must say, I was surprised at how much hot water one person uses every day.  As a general rule, one person will use between 75 - 100 litres of hot water a day, which is a relatively wide range, but for a 3 person apartment, you could expect to use between 20,000 and 25,000 litres a quarter - check this out on your bill. 


To work out your average daily usage, divide the total number of litres from your bill by the number of days in the quarter (between 90 – 92).  That will give you your average daily usage for the quarter.


When you do your daily meter readings, you can compare your average to actual, to see if that lines up.


If your readings are not within the band, then you may have an issue with your usage and so think about why it would be higher than average and see if reducing excess usage improves the position.  


How much water do I use in my shower & what should it cost?


The biggest single contributor to your hot water cost is your shower.  There are ways to check whether you have a high hot water usage in your shower - obviously long showers, but also, the efficiency of your shower rose.  Check the flow rate for your shower and see if it is low, generally between 6 - 9 litres a minute.  A tip for how to check usage and what to do about it is noted later.  


If your shower uses 8 litres of hot water per minute, and you have a 5 minute shower (including time to get the water hot), then you’ll use around 40 litres of hot water.  Hot water should cost about $0.015 (ie one and a half cents) per litre.  So, your average shower should cost you about 60c. 


You can do this using the information on your own bill to check your costs and see whether they are as expected.  All you need to do is to look at your bill and get your conversion factor and the price per MJ that your retailer charges you.  Here’s how I did it – (you’ll be able to work this out by looking at your bill):


4 decilitres = 40 litres x conversion factor (mine is 0.504)  =  20MJ of gas used


Under my plan, I am charged around $0.027 per MJ, so total cost of about 55c


Next steps


If you have exhausted all of the above avenues, then you must arrange for a plumber to confirm whether there are any leaks in the piping within your unit and your apartment complex.  EWON advises that this is a requirement before your energy retailer will concede that there is a problem.  It sounds unnecessary, but you will need to arrange this.  If you are renting, then either your body corporate or landlord has to pay for this.  Speak to the Tenants Union if you have any issues getting it done, as they can apparently require the landlord to undertake the work.


Hints to reduce your hot water usage


Water efficient shower head


A water-efficient shower head with a low flow rate will help reduce your usage, with no noticeable reduction in the quality of your shower. 


If you don’t know the efficiency of your existing shower rose, check the flow rate by turning on the shower filling a bucket for 10 seconds. Measure the amount of water collected in litres and multiply this by 6 to give you a flow rate per minute.


For example, if you collected three litres in 10 seconds, the flow rate is 3 x 6 = 18 litres per minute.  Generally, a low flow rate is between 6 and 8 litres per minute.  Average rates are around 9 litres per minute. 


If your flow rate is on the high side, think about getting a pressure limiting valve (not practical with a Common Hot Water unit) or buying a shower rose with a lower flow rate.




If you have taps (not mixers), and you are right handed, then when rinsing items at the kitchen sink, you will invariably turn on the hot tap (it’s on the left and you generally hold the plates / utensils in your right hand) - this can lead to a significant increase in hot water usage, especially if you have to wait long periods for the water to get hot.


Sequential showering


Try and arrange for people to shower straight after one another - your apartment can be a long way from the central water heater, so you waste hot water each time you keep the HW tap running waiting for the water to get hot.




Finally, if you still get no joy from the retailer, and have exhausted all avenues of enquiry, then you can engage EWON, the Energy Ombudsman.  They can help, although their terms of reference are relatively narrow, and they have a limited remit - if you cant prove to them that there is a problem, then they really cant take any action. 


Some have expressed concerns that EWON are very slow to respond.  My experience is the opposite - they have been both helpful and very responsive.  I think they need to have the ammunition to be able to ask the retailer the right questions, so the better prepared you are, the better the result will be.


If you mention the Ombudsman in discussions with the retailer, you will be allocated to the "special" resolutions team.  In my experience, these people aren’t any better at helping you understand your usage issues, but they are better at discouraging you from taking any further action.


Myths & misconceptions


There are a number of misconceptions out there as well.  Have a look at these:


The mythical “freeloaders”


Some are convinced that "freeloaders" are using hot water but not paying for it, typically because the occupants did not register for gas either at the time the apartments were constructed, or when they moved into their apartment.  For the first case, each apartment is assigned a Delivery Point Identifier (DPI) or Meter Registration Identification Number (MIRN) and all meters in the apartment are assigned to that dwelling via this ID (you can see this on your bill). 


Although Jemena owns the meter, the builder arranges for a retailer is assigned to each gas meter at the time of installation, and so all gas points for each apartment are registered and logged.  When you move in you are still free to change retailers, but all meters assigned to the DPI / MIRN for that apartment - it is not possible to split or disaggregate the meters to hide usage.   Hence, when bills are issued, they have both gas points - you cant only have one (otherwise theoretically, you could activate and pay for your cooktop, but your hot water would be free). 


In the second case, if you move into an existing apartment, and don't register with a gas retailer, then the retailer for the previous occupant keeps track of your charges and send you a bill to your address to "the Householder", and takes steps for collection if it is not registered and paid.  You dont absorb the cost of this, any risk of non recovery rests with the retailer.


What is a conversion factor?


The “Conversion Factor” is really the “MJ used per litre of water" – in other words, it is the amount of energy that is used to heat each litre of the hot water that you consume.    


Jemena will not tell you how they determine the conversion factor, or what it means.  Indeed, you have no contract with them, only with your retailer.  So, you need to get your retailer (who does have a contract with Jemena) to ask Jemena to check it.  They will be able to do this for you if you ask.  However, an easy work around for this is to talk to your neighbours and see what their bills are - find out how many litres of hot water they use and see what the MJ used per litre are - this is the conversion factor noted on your bill.  While the factor changes seasonally due to gas pressure etc, it should be roughly consistent between all occupants in your apartment for each quarter that you are billed.  

AGL Community Manager

Fantastic post @Uma! Many thanks for taking the time to share all that info in one place - hopefully others will find it useful.

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