25 June 2020

Cost of continuous flow hot water system?

| CanberraGirl2002
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Hi all,

Newbie here – please be kind 🙂 Our electric tank hot water system has died, leaving us without hot water. Instead of paying to get it fixed we thought we may as well get a continuous flow hot water system (gas) installed, as we’ve been talking about it for a while, but have never gotten around to making it a priority.

Our quote has come back at just under 4K. As we need to book it in asap I thought I would throw it out on RIOTACT to see if anyone else has had one installed and what the cost was. I think much of the cost is in the installation. Just as background, we are in an old (circa 1950-60) four bedroom home with two bathrooms.

Thanks in advance!

If you’re looking for more information on hot water systems, check out our recently updated article on the best hot water system repairers in Canberra.

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I would be wary of installing a new gas line with the volatility in the gas market at the moment – obviously impossible to predict but most projections have prices more than doubling in the next couple of years. Based on what price you’re quoting I assume you’re having to have gas connected or at least the pipes upgraded to allow for the high flow rate of gas required for instantaneous systems. I personally wouldn’t install anything gas any more.

If you have a largish house it’s worth considering multiple units – for instance if your bathrooms and kitchen are at opposite ends of the house you will lose a lot of heat (as well as waste water) on long pipe runs. You could consider a small point of use storage electric system for the kitchen – like a 25 or 50L tank you could keep under the sink, or else an instant electric. Then you could look at a solar or heat pump for the bathrooms (as close as possible). I personally would recommend a heat pump – the technology (the same as for an air conditioner) is well established overseas and there are plenty of great options available on the market now. The Edson Sanden (? something like that) one uses CO2 instead of a normal refrigerant and is great at the low temperatures we get in Canberra. There is some noise from the compressor unit so you don’t want to install right outside bedrooms or near neighbours. Some models can operate on off-peak too to save even more.
If you go for solar, evacuated tubes are a must in our climate and you could consider oversizing your panels to allow for less sun in winter (if necessary covering them over in summer to prevent overheating).

pajs said :

JC said :

Oh forgot to say with traditional tank heaters it has been the law for about 20 years that if you have a tank replaced it needs a tempering valve set to 60c. So even though it may be easy to up thermostat on a tank beyond this you will wont get super hot temps like some people are talking about as the tempering cable will mix in cold water for reduce it.

You should still be able to run a direct line from a higher-temperature supply to your kitchen sink, so long as the rest of the pipes have a tempering or thermostatic mixing valve between the supply and the use. The intention of the regulation is to stop bathroom scalds, not the washing up.

Yep – plumber quite legally set up for me a bypass system so that the bathroom hot water is 55% but the kitchen water is hot as.

If you install instant hot water in Canberra you have to have a system that preheats the water in a tank to a temperature that will allow a decent instant flow. There is no instant hot water system designed for near-zero water temperatures. You only usually find them in rentals, where the landlord doesn’t care whether the tenant gets a decent hot shower!

CheekyChicken said :

This is something we looked into with a great deal of interest.

We have a 20 place child care centre that needed a Hot water solution for 2 bathrooms and a kitchen.

Being a not for profit we needed to be absolutely certain that the unit we went with was first and foremost good for the environment and had the least amount of running costs and future maintenance / service costs.

Electric Tank = out of the question.
SOLAR hot water = Very expensive even with rebates, be cautious about what booster you have. other wise its just an electric tank on terrible winter days. or gas… with the added benefit of another gas bill.
Solar can sit there for 15 years potentially without any serious maintenance issues, but if it does not it can be very costly. Ongoing payback in our opinion was not worth the outlay as it is not as high a rebate as it used to be.

Gas / instant or similar. Cheap to buy, expensive to install depending on your installer.
The ACTEW shop as well as the government department that actually gives rebates for improving commercial premises advised against installing a gas unit as the projected cost of gas along with the initial purchase outlay and installation outlay were deemed not viable.

At point instant. = super popular in the UK mainly due to lack of ability to run pipes etc. AUST = the lucky country for that, easy timber framed houses generally. ( = poor heating and cooling retention but thats another topic)

They suggested solar or heat pumps.

We ended up getting a Quantum Energy heat pump. work down to some ridiculous minus temperature in winter, so no issues in Canberra.

Its their commercial unit, however they make a couple of residential units as well.

These things run with a tiny electric motor like a fridge basically and are WAY more efficient at giving your hot water day, night, sun shining or not… 🙂

There are rebates for these as well i believe.

The literature available online will show you comparisons between gas, elec, solar and the heat pumps so see for yourself whats better.

http://quantumenergy.com.au/products/heat-pump-vs-electric-solar-gas/
The ultimate hot water is geo thermal heat pump, but who has 20k to spend on hot water HAA HAA.

I installed a Dux heat pump HWS about 6 years ago. It was supplied without the “sub-zero chip” but when this was added it delivered hot water on the same basis as the old on demand electric I had for 10 years.
Electricity consumption decreased 30% immediately. The only maintenance problem I am aware of is replacement of the sacrificial anodes is required every 5 – 10 years. I used to replace elements in the old on demand electric every 2 – 3 years.
With heat pump air heating and cooling, double glazing, ceiling insulation and LED lighting I have reduced electricity consumption by half over 5 years.
I won’t contemplate gas due to a family tragedy caused by a faulty gas heater many years ago.

dungfungus said :

Be aware that Australia has signed massive delivery contracts for exporting gas and on current projections we will not meet them so domestic gas supplies will become even more expensive.
Once again, that filthy black stuff will save all civilised Australians who use electricity.

Yes we are very good at this, selling our resources overseas to make more money, while not caring about our own people. Look at fuel prices in countries that produce fuel. They keep them low by not selling everything overseas and buying it back.

Queanbeyanite9:56 pm 19 Feb 15

Pros:
Never runs cold, handy if we have guests,
set the thermometer and 20 seconds later you’ve got hot water at the right temperature, no micro adjustment of the hot and cold taps for a minute or so.
bump the hot tap with your elbow and the temp doesn’t budge.

Cons:
Gas is going to get a lot dearer.
Can’t set the temp below 38 degrees or it cuts in and out, not good on hot days when you want a cooler shower.

Referring to the post above about the dishwasher:
We had our old one replaced recently and the installer said we should only connect it to cold water.
Hot water entering a cold dishwasher expands and contracts the seals quickly, reducing their working life.

CheekyChicken9:53 pm 19 Feb 15

This is something we looked into with a great deal of interest.

We have a 20 place child care centre that needed a Hot water solution for 2 bathrooms and a kitchen.

Being a not for profit we needed to be absolutely certain that the unit we went with was first and foremost good for the environment and had the least amount of running costs and future maintenance / service costs.

Electric Tank = out of the question.
SOLAR hot water = Very expensive even with rebates, be cautious about what booster you have. other wise its just an electric tank on terrible winter days. or gas… with the added benefit of another gas bill.
Solar can sit there for 15 years potentially without any serious maintenance issues, but if it does not it can be very costly. Ongoing payback in our opinion was not worth the outlay as it is not as high a rebate as it used to be.

Gas / instant or similar. Cheap to buy, expensive to install depending on your installer.
The ACTEW shop as well as the government department that actually gives rebates for improving commercial premises advised against installing a gas unit as the projected cost of gas along with the initial purchase outlay and installation outlay were deemed not viable.

At point instant. = super popular in the UK mainly due to lack of ability to run pipes etc. AUST = the lucky country for that, easy timber framed houses generally. ( = poor heating and cooling retention but thats another topic)

They suggested solar or heat pumps.

We ended up getting a Quantum Energy heat pump. work down to some ridiculous minus temperature in winter, so no issues in Canberra.

Its their commercial unit, however they make a couple of residential units as well.

These things run with a tiny electric motor like a fridge basically and are WAY more efficient at giving your hot water day, night, sun shining or not… 🙂

There are rebates for these as well i believe.

The literature available online will show you comparisons between gas, elec, solar and the heat pumps so see for yourself whats better.

http://quantumenergy.com.au/products/heat-pump-vs-electric-solar-gas/
The ultimate hot water is geo thermal heat pump, but who has 20k to spend on hot water HAA HAA.

pajs said :

JC said :

Oh forgot to say with traditional tank heaters it has been the law for about 20 years that if you have a tank replaced it needs a tempering valve set to 60c. So even though it may be easy to up thermostat on a tank beyond this you will wont get super hot temps like some people are talking about as the tempering cable will mix in cold water for reduce it.

You should still be able to run a direct line from a higher-temperature supply to your kitchen sink, so long as the rest of the pipes have a tempering or thermostatic mixing valve between the supply and the use. The intention of the regulation is to stop bathroom scalds, not the washing up.

That’s what happens in my house.

JC said :

Oh forgot to say with traditional tank heaters it has been the law for about 20 years that if you have a tank replaced it needs a tempering valve set to 60c. So even though it may be easy to up thermostat on a tank beyond this you will wont get super hot temps like some people are talking about as the tempering cable will mix in cold water for reduce it.

You should still be able to run a direct line from a higher-temperature supply to your kitchen sink, so long as the rest of the pipes have a tempering or thermostatic mixing valve between the supply and the use. The intention of the regulation is to stop bathroom scalds, not the washing up.

Oh forgot to say with traditional tank heaters it has been the law for about 20 years that if you have a tank replaced it needs a tempering valve set to 60c. So even though it may be easy to up thermostat on a tank beyond this you will wont get super hot temps like some people are talking about as the tempering cable will mix in cold water for reduce it.

VYBerlinaV8_is_back said :

carpediem said :

dungfungus said :

Stay with electricity, better still put in a solar with electric boost.
Gas is outrageously expensive.

With 4 adults and occaisonal warm water washing – I’ve actially found my gas hot water to be substantially cheaper than electricity. Could be the choice of systems?

Your $4K quote might also include getting the natural gas lines to house if they hadn’t been previously connected. If so, you wont get that component of the cost any cheaper.

We had a rinnai (sp?) infinity gas system at my last house and it costs three fifths of nothing to run, it was insanely cheap.

That said, it takes time for hot water to reach extremities of the house (the bigger the house the worse the latency), and also cost a lot more to install in the first place.

I’m about to replace our normal gas hot water unit and am currently thinking that another standard gas unit might well be the best bet. It still doesn’t cost much to run, keeps up with our hot water needs without issue and costs substantially less to install in the first place.

Decisions, decisions…

If the OP doesn’t have gas already connected then it makes no sense to do it just for heating water. The daily “standing charge” for a gas service is about 65 cents a day. The gas costs extra.
Be aware that Australia has signed massive delivery contracts for exporting gas and on current projections we will not meet them so domestic gas supplies will become even more expensive.
Once again, that filthy black stuff will save all civilised Australians who use electricity.

With the infinity the temp is set at 50c unless you have controllers where it can go to 55. That’s said had one for 15 years set at 50 and never had issues with cleaning the dishes.

I added controllers later on which was good. Means when having a shower you set the temp you want and don’t waste money heating water only to cool it by mixing in cold water. I found 42 in the ensuite was quite comfortable or 41 in the main shower which was close to the unit.

Time wise it takes about 15 seconds for the ensuite to come to temp and the main bathroom and kitchen under 5 seconds. You can buy an add on preheated to get around this issue but requires a return pipe to be run from the further most outlet back to the heater.

So moral to for it but get controllers. For the infinity they are about $120 retail for the standard type no doubt an installer will jack the price significantly.

VYBerlinaV8_is_back12:50 pm 19 Feb 15

carpediem said :

dungfungus said :

Stay with electricity, better still put in a solar with electric boost.
Gas is outrageously expensive.

With 4 adults and occaisonal warm water washing – I’ve actially found my gas hot water to be substantially cheaper than electricity. Could be the choice of systems?

Your $4K quote might also include getting the natural gas lines to house if they hadn’t been previously connected. If so, you wont get that component of the cost any cheaper.

We had a rinnai (sp?) infinity gas system at my last house and it costs three fifths of nothing to run, it was insanely cheap.

That said, it takes time for hot water to reach extremities of the house (the bigger the house the worse the latency), and also cost a lot more to install in the first place.

I’m about to replace our normal gas hot water unit and am currently thinking that another standard gas unit might well be the best bet. It still doesn’t cost much to run, keeps up with our hot water needs without issue and costs substantially less to install in the first place.

Decisions, decisions…

You can get a solar hot water system with an electric boost to the storage tank for about that $4k figure. Less exposure to gas prices that way.

Rollersk8r said :

but I think standard units only heat the water to 60 degrees. Some people say this is not hot enough to wash really dirty dishes etc.

My solar tank is heated to 70 degrees, but the temperature mixer then cools the water to most of the house. The exception is a separate line running into the kitchen hot water tap that bypasses the mixer. Water cooled by the mixer is definitely not hot enough to hygienically wash dishes.
My last house had water at 85 degrees running into the kitchen sink. Now that cleans dishes well.

dungfungus said :

Stay with electricity, better still put in a solar with electric boost.
Gas is outrageously expensive.

With 4 adults and occaisonal warm water washing – I’ve actially found my gas hot water to be substantially cheaper than electricity. Could be the choice of systems?

Your $4K quote might also include getting the natural gas lines to house if they hadn’t been previously connected. If so, you wont get that component of the cost any cheaper.

dungfungus said :

Stay with electricity, better still put in a solar with electric boost.
Gas is outrageously expensive.

I agree about the gas. My solar has an electric booster. The builder wanted to have a gas booster, but I said no, as I didn’t want to pay for a service every month, even if I used no gas. My house only needs a wood fired stove to heat for very rare use, and doesn’t need any other heat source. Plus I didn’t want to cook with gas. So the only use gas would have would be boosting the solar hot water system one month a year. So I stuck with electricity. My electricity use triples for the month my booster is on, raising the bill (with service charges) to about $170. Next winter I shall only boost in off peak, in an attempt to lower that.

dungfungus said :

Stay with electricity, better still put in a solar with electric boost.
Gas is outrageously expensive.

I find the most expensive thing about gas are the supply charges.

My old house had gas cooking, heating, and hot water, and the supply charge for each bill was typically more than the actual gas I used.

If I were building a house, I’d be tempted to go all electric, as I imagine any increase in electricity costs would be more than offset by the circa $300 a year not being paid in gas supply charges.

Rollersk8r said :

We put one in, a few years ago, for a bit over $3000. Electricity bill immediately reduced by 20% – and we were very happy to reclaim the space the tank was taking up in the laundry.

A couple of points to be aware of though! Firstly, the instant gas system works very well for us, thanks to having a tiny house (as already posted). There is still a bit of a delay.

Secondly – and most importantly – is the temperature of the unit. I’m not 100% sure this is still current information – but I think standard units only heat the water to 60 degrees. Some people say this is not hot enough to wash really dirty dishes etc. We purposely sourced a hotter unit and have no problems with it being hot enough.

Make that 50 degrees C. Being a typical mindless bureaucrat nannystate regulation, this means that an older house with little or no insulation on the pipes makes the hot water too cold by the time it gets to the kitchen sink to shift grease. A bit of searching for the manual for your model on the internet usually finds the instructions you need to make it run hotter.

We had one installed several years ago to replace a failed electric storage tank (not off-peak) and are still happy with it. But as dungers says, gas is getting noticeably more expensive to run it. It was cheaper to start with, but I don’t think so anymore. Also make sure the installer puts it where the pipes will have the shortest run. Ours was installed for their convenience on the day and we ended up with long runs of pipe to join back to the failed water tank pipes in the roof which also doesn’t help heating efficiency.

We put one in, a few years ago, for a bit over $3000. Electricity bill immediately reduced by 20% – and we were very happy to reclaim the space the tank was taking up in the laundry.

A couple of points to be aware of though! Firstly, the instant gas system works very well for us, thanks to having a tiny house (as already posted). There is still a bit of a delay.

Secondly – and most importantly – is the temperature of the unit. I’m not 100% sure this is still current information – but I think standard units only heat the water to 60 degrees. Some people say this is not hot enough to wash really dirty dishes etc. We purposely sourced a hotter unit and have no problems with it being hot enough.

Do the electric systems require three phase?

Stay with electricity, better still put in a solar with electric boost.
Gas is outrageously expensive.

If you have to pay that much, why not pay a bit more and have solar installed. I only need the booster about one month a year. The rest of the year the sun heats the water. That’s means for eleven months of the year I don’t pay for power to heat water. The time the booster is needed could likely be reduced if I added more tubes.

We had one installed last year for about $3600. It used an existing external power outlet so that cut costs by a small amount.

There are limitations as to where they can be installed (distance from windows etc) but try to get it as close to your wet areas as possible. We had to put ours at one end of the house and it takes an age for the hot water to reach the kitchen.

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