Instant v stoarge Howt water service

Hi eceryone
I have looked through the archive and found a little bit on this subject but not much. If it has been done can someone direct me to the appropriate post please.
Doing a reno and will be shifting an old HWS (2 star rating!!!!!). Tossing up between storage and instant. Instant looks good due to size and star rating. We are very water conscious and would like to be more efficient gas wise. Some say it takes time for taps to heat to desired temp, so wastes water but that's okay, we often collect this water anyhow. We also tend to have baths more than showers and very rarely would two hot water taps be on simultaneously.
The thing that is worrying me though is people saying there may be a need for new gas pipes and water pipes? We have just got a Brivis ducted gas heating installed and no need for new pipes.
Can anyone tell me in what situation I would need need water or gas pipes? I live in Melbourne and as I said have gas ducted heating and water pressure is great. Any thoughts you think would be helpful would be appreciated.
Cheers
McBlurter.

A woman walks into a bar and asks for a double entendre, so the barman gave her one!

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Originally Posted by Mcblurter

Can anyone tell me in what situation I would need need water or gas pipes? I live in Melbourne and as I said have gas ducted heating and water pressure is great.

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The instanteneous gas HWS uses a large quantity of gas to quickly heat the water when required whereas a storage heater doesn't as it will heat slower over a longer period of time.

When I looked into it I was told that the existing gas line, which ran past the proposed HWS, of I" diam would not be sufficient and that it would have to be replaced with a 1 3/4" pipe.

This would have virtually doubled the cost of the unit, so I went to an electric storage HWS at a quarter of the cost of the proposed gas one.


Peter.

I love mine. Yes had to add a new gas pipe but I needed that anyway, they do take a large pipe but if you've got gas ducted you may be OK?

Not sure about the 1 3/4 above ... that's huge! I have a 1 inch main gas line in melbourne that splits into two 3/4 inch pipes feeding the Hotwater an ducted heating.

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Originally Posted by OBBob

Not sure about the 1 3/4 above ... that's huge! I have a 1 inch main gas line in melbourne that splits into two 3/4 inch pipes feeding the Hotwater an ducted heating.

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The existing gas pipe that we wanted to tap into runs to the ducted heating which was a 1".

The plumber enquired from the gas shop and the manufacturer of the HWS and the existing ducted heating as to the pipe needed and that was their advice.

Something to do with if both started up at the same time I suppose, but it is definitely something to factor into the equation and should be enquired about when pricing the two options.


Peter.

The pressure requirements are important ... maybe the pressure is a little lower in your area?

McBlurter - The pressure requirements are in the manual that you can download for the Integrity ... I assume they'd all be similar.

As for different water pipes ... don't see why that would be the case ... my are normal. My gas bill certainly dropped when the old inefficient storage unit was replaced. But you may get the same drop by using a newer more efficient storage unit.

My other main consideration was the size. Being close to the city ... space is a premium ... probably not as high on the importence list for Sturdey in Donvale.

thanks OBob and Sturdee.
Will check out the specifications and see what they say.
Cheers
Mcblurter

Hi
Just checked the Rinnai specs and found this
** All Rinnai INFINITY models will operate at lower pressures, however the specified flow rates may not be achieved. Gas pipe sizing should be performed using an approved sizing chart, as specified in AS 5601 / AG 601. Water pipe sizing should be in accordance with AS 3500.

Can anyone shed some light on these?
Does anyone have both Ducted heating and instant HW on a 1" pipe (is 1" standard?) and have any problems?
Cheers
Mcblurter

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Originally Posted by OBBob

My other main consideration was the size. Being close to the city ... space is a premium ... probably not as high on the importance list for Sturdee in Donvale.

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As the house, without the garage, is only approx 40 squares in the old measurements and I'm on a quarter acre block, space is not a major issue.:D In fact our BBQ area is bigger than most units backyard.

But I never have enough space in the workshop.


Peter.

Gathering more info.
We have a 1/2" pipe and seems like instant HWS would need at least a 3/4 to 1" pipe.
So next question is what size pipe do I put in. do I need a 1 1/4" pipe to cover the 1/2' and 3/4"? or Would a 1" pipe be adequate, I'm not a plumber so unsure of how the pipe size thing works?
Is it a costly job, any ball park figures? Probably about 6mtrs from mains to HWS.
Cheers
McBlurter

So.....solar is not an option?

Hot water consumes about 1/3 of all energy needs of a house.

Do your bit for then environment and seriously think about solar or a heat pump type system. Quantum Energy

Chris

The most energy efficient hot water is off peak electric. With solar added it can only save more. The pressure is not good though. In country area's with plenty of sunshine you would be mad to do it any other way. In Melb mains gas area, storage is more efficient. In my own personal opinion, instant gas is for people who are obviously not on the poverty line and struggling just to meet house repayments, and can afford extra gas costs.

McBlurter,
As OBBob says, pipe size will depend on gas pressure and pipe distance. You mentioned 6mtrs. Whats the pipe distance to your Brivis unit? Check the supply pressure from your meter/regulator. As an example only...if the pressure is between 2.75-5kPa, 25mm (1") copper pipe will supply 600MJ/h upto 12 metres.
Mate, my best advice would be to get your local gas fitter out to have a look. If you tell him the gas consumption in MJ/h of your new Hot water unit and your Brivis unit, he'll size the pipe within seconds.

With instantaneous you have greater efficiency ( not by much) but a reduced flowrate to your taps- good if your water wise, bad if you like blasting showers.

Storage has full flow rate but heats water when you dont need it to.

With Instantaneous heaters you sometimes have trouble fitting water saver devices- eg shower head- because of the reduced flow rate. But your already using less water so you dont really need the devices anyway.

In sa plumbers/ house holders can ask for the gas pressure to be increased from 1.4 kpa to 2.75 kpa- this will let us install big heaters with no pipe size change. Maybe you can too?

If you have a plumber / gasfitter come around they will be able to tell you on the spot if you need bigger pipes so you can make a decision then.

Thanks again everyone
A few issues raised.
I've looked at quite a number of units before solar, electric and heat pump. If I can remember rightly the heat pump needs a certain outside temp to work efficently so would have to have a backup, also has electricity needs. Solar is a bit too costly to set up initially and storage again heats water when don't need it, plus always forget to turn it off during holidays etc. Will be looking at installing some solar panels, but holding off until after next election. Seems to be a lot of research and develoment in this area and hopefully some larger rebates on the way!!!
We are very enviro friendly and wanted to stay away from electricity as much as possible (not only greenhouse gases but also uses lots of water to produce it) As I have said, we don't use a lot of water (229 lt per day for two adults and two children) so think would be using a lot less gas than we do now. Have installed ducted gas but again see the use of this as minimal (we don't need to live in T-Shirts in winter!!!)
I will speak to a professional. I really like this forum as it helps me get to know what I need to know so I can ask the right questions!!! I can then do a bit more research so when I do speak to th eprofessional I don't waste his time andmine with stupid questions about stuff that isn't important, or using jargon that isn't correct.
So thanks again. Please feel free to make any more comments about any of these issues, especially the environmental impact.
Cheers
McBlurter

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Originally Posted by peter_sm

........In my own personal opinion, instant gas is for people who are obviously not on the poverty line and struggling just to meet house repayments, and can afford extra gas costs.......

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???

We converted to an instant system (Rinnai 26) about 2 years ago. Best thing we have done. Our gas bill is far less than our electricity bill ever was, and our overall energy consumption is much less. I can't see how an off peak electric system can be anywhere near as efficient as an instant gas system. We are also looking to put in a number of water tanks to reduce our water 'footprint' and hoping to tie them into the hot water system. The gas mains is 1 inch and this services our water heater, cooking and two gas fire places - no problems.

In the next 5 years, I think we will also look to supplement our water heating and further reducing our footprint by installing a solar system.

If I get time, I will sit down and analyse our power/water usage since 2001 and that will show a definitive comparison between the stored system and the instant system.

Cheers

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If I can remember rightly the heat pump needs a certain outside temp to work efficently so would have to have a backup,

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A heat pump system will work all the way down to -10 degrees C.

Hi Grunt
You seem pretty keen on the Quantum HWS which I have been looking into. I see it is connected to electricity and wondering what does it use electricity for? It compares the greenhouse emissions with a standard electric system but not a gas one so unsure how much greenhouse gas emissions it saves as it uses some electricity compared to gas? Also a pity we can't get a smaller tank, smalledst is 270lt. We have a 135lt gas one and suits us fine. Also do you know what the ongoing cost of changing the annode every 5 years is and can a handyman do that?.
Don't expect you to know all the answers, I could speak to a retailer, but thought you may have already looked into is as you are recommending it.
Cheers
Mcblurter

I'm not sure about the comparison to gas. I'm in the country so only bottled gas is available.

I don't know about the cost of annode servicing.

We're also using ours for heating the house as well be installing water filled radiators. Quite cheap for house heating.

We managed to find a brand new Quantum split system off of eBay for $1400 which sort of clinched the deal for us.

Bottled gas is very expensive.
$1400 would certainly clinch the deal for me as well!!!
May have to give ebay a look.
Is yours up and running already? How are you finding it?
Cheers
McBlurter

Anode replacement is a 20 min job on a storage heater . 10 of it to find the very large sogket to remove the old anode, would probably be similar on a quantum, you could try asking the manufacturer

I used to have a gas storage system and upgraded to instant gas service. Both were on bottles. We had to upgrade to a larger diameter pipe.

Since we have upgrade our gas bills are half, and we use a lot less water.

How? Well you are not heating water up in case you need it, there is no pilot. also you get controller which you can pre-set the water temp. this means that you don't cool down your hot water by adding cold water to it. So now we save on water as well - down by half as well.

We have bottled gas and it costs for a family of four, also running our gas cook top about $50 a quater - plus a yearly access fee of $32.

Origin is my supplier in case you are wondering.:)

Thanks mdfdust and everyone
Sent an email to the heat pump people regarding comparison of greenhouse gas emissions with natural gas and a few questions reagrding its use of electricty but haven't heard back from them.
If have to get a new gaspipe then tossing up between instant gas and solar with a gas booster as cost probably around the same. Anyone had any experience with solar that they would like to share? Seems like the bigger the system the more rebate, but again don't want to heat water we don't use, so any suggestions for smallish tanks and systems to check out would be appreciated.
Cheers
Mcblurter

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Originally Posted by peter_sm

The most energy efficient hot water is off peak electric.
In my own personal opinion, instant gas is for people who are obviously not on the poverty line and struggling just to meet house repayments, and can afford extra gas costs.

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Cant see how that could be so Peter. Here in NSW storage systems are extinct because we have the BASIX (building sustainability index) assessment required for all new houses & reno's over $100,000 ( from July reno's over $50,000). Gas instantaneous are very efficient, thus their popularity. They're also very cost effective compared to solar.

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Originally Posted by peter_sm

In Melb mains gas area, storage is more efficient. In my own personal opinion, instant gas is for people who are obviously not on the poverty line and struggling just to meet house repayments, and can afford extra gas costs.

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I'm afraid I have to agree with the others also Peter. I 've recently moved house and we have gone from a 135l storage unit to a instant unit( a fairly old Bosch one at that) and our gas bills are about 35% less. All other gas uses remain the same- our new house even has the same stove as our old one.
I would think a new unit would be even more efficient than our one.

Bruce T.

Thanks everyone for your comments.
I have decided to go for a 5 star 130lt capacity gas storage tank. Will use a lot less gas than our current 2 star one so a vast improvement. Will save us some money also so we can save for some solar panels at a later stage (Hopefully both political parties will have a huge rebate for solar panels!!!!)
Thanks again
McBlurter

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Originally Posted by peter_sm

The most energy efficient hot water is off peak electric. With solar added it can only save more. The pressure is not good though. In country area's with plenty of sunshine you would be mad to do it any other way. In Melb mains gas area, storage is more efficient. In my own personal opinion, instant gas is for people who are obviously not on the poverty line and struggling just to meet house repayments, and can afford extra gas costs.

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Nope - most energy efficient (aside from solar only which is impractical for most installations at present) is solar/ gas using a suitably sized storage unit, but as always capital outlay is higher. Remember that electricity is relatively efficient at point of use, but we lose 70% or more in producing it and transmitting it to where we need it. Not sure what is mean by pressure not being good - solar power units are mains pressure for the delivery of the hot water to taps - the lower pressures are through the heating units - by convection, but now mostly by a small pump. Costs for gas storage heating is mostly less than off-peak electricity - and environmentally much better.

Some issues to think about:

If you do intend to go solar then your purchase now needs to be a storage tank not instantaneous so you can plumb in the solar array at a later stage. But, if you had the money you could install the gas Rinnai or similar now and a full solar storage rooftop unit without needing to connect an electric booster as the solar is plumbed through the instantaneous (which only fires up of the temp of inflow is below what you have set for use).

The savings from a gas instant use system such as the Rinnai [I have had one for years and the gas pipe is 19mm (from the meter to the devices) that is shared with a large Brivis central heater] comes from 3 characteristics:
a) the gas is cheaper per Kw output and efficiently burned
b) you use heat only when you need hot water and
c) most importantly you heat the water only to the temperature you need to use it (37-42 or so in bathrooms and 50-55 to wash up in kitchen).

If you want to shower at 42 degrees you set the temp to that and the heater has only to heat the water up the difference between the ambient water temp (say 12-20 degrees) and 42. In a storage heater you heat all water to 60 or more, keep it at that temp whether you are using it or not, then mix cold water into the shower to cool it to the temp you need - wasteful indeed.

There are plenty of web sites on this stuff - start with:
http://www.greenhouse.gov.au/

especially

http://www.greenhouse.gov.au/yourhom...nical/fs42.htm

Note - physically running your own pipe work is probably OK, but it is not smart to make the soldered/brazed/compression connections if you are not a licenced plumber - especially for gas. Illegal in all states too of course.

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Originally Posted by Kiwibrucee

I'm afraid I have to agree with the others also Peter. I 've recently moved house and we have gone from a 135l storage unit to a instant unit( a fairly old Bosch one at that) and our gas bills are about 35% less. All other gas uses remain the same- our new house even has the same stove as our old one.
I would think a new unit would be even more efficient than our one.

Bruce T.

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I am guessing but that size unit might be a bit small so prevent you using solar with it later - but check with your gas energy supplier.

And of course biggest savings can be made by simply showering for shorter times, and using less hot water generally - cold for washing, use eco cycles on a dishwasher (or washing up by hand - don't believe the nonsense about hand washing up using more than a dishwasher!) etc.

Another saver is to wrap additional insulation blanket around your storage heater - even the new ones benefit. Have to make sure with gas that you do not block intake and exhaust vents, but this is a cheap and simple way to prevent heat loss - especially if on an outdoor unit.

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Originally Posted by Sturdee

The instanteneous gas HWS uses a large quantity of gas to quickly heat the water when required whereas a storage heater doesn't as it will heat slower over a longer period of time.

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It takes the SAME amount of gas to heat the SAME amount of water whether it is used in a storage heater or instantaneous heater.

The requirements of a HWS generally dictate the need for the type of HWS chosen.

The instantaneous gas is by far the most economical as you ONLY heat the water you NEED/WANT. Storage HWS's keep the stored water hot ALL the time, so use gas frequently to keep the temperature up. This means that if the HWS is NOT used during the day, then the storage heater is using gas to keep the water hot for no real reason.

The major difference between the two types and the need for one over the other is pressure. The pressure is generally better from the storage type of system and therefore handles more taps in use at the one time. However the newer types of instant HWS are VERY GOOD and still very efficient. They can usually handle two taps at once. PLUS with some of the instant HWS you can regulate the temperature very easily.

Sure the instant uses a lot of gas "instantly", but no more than what is needed at the time, and it uses no more than that of a storage HWS, and usually much less as it is NOT keeping the water hot while the hot water is not required.

Economically the instant HWS is the best, providing the pressure and/or taps in use are acceptable by the user.

Instant HWS also work very well with solar HWS. They "kick in" when the (solar) stored water drops below the temp set at the HWS. This IS MUCH CHEAPER to run than the electric heater in the solar tank.

Water pressure is the ONLY consideration.

If you have kids that use lots of water, then the instant HWS will keep up with the continual needs, but not necessarily with 3 or 4 taps at once.

With storage HWS the pressure may be available at these 3 or 5 taps, BUT you will run out of hot water very quickly. The storage heater takes MUCH longer to heat up the incoming water. By design it is not as efficient as the instant HWS.

Basically with instant HWS you NEVER run out of hot water.

If I had to install a HWS for my wife and myself it would be an instantaneous HWS without doubt.

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When I looked into it I was told that the existing gas line, which ran past the proposed HWS, of I" diam would not be sufficient and that it would have to be replaced with a 1 3/4" pipe.

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That's a hell of a lot of gas! :D :D

I've noticed a new trend on a few houses lately, which is to have mutiple instant HWS's. I guess to reduce the distance the water needs to travel in the pipes. They might have one near each bathroom or kitchen / bathroom if there is a distance between them.

I guess in the scheme of things if building a new place it isn't a lot more money and I imagine you would lose quite a lot of heat from even the insulated pipes ... not to mention all the cold water watsed waiting for the warm to come through.

Not sure I'd do it but I have seen it a couple of times now. :)

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Originally Posted by SilentButDeadly

So.....solar is not an option?

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He lives in Melbourne:doh:

What's it like to need a gas heating system:roll:

HH.

I grew up with a instantaneous gas system about 20 years ago in Britain that also did the central heating, which gave the hot water priority, so if everyone had a shower in the morning, the house gradually got colder and colder... We installed a new gas instantaneous hot water system ( no need for central heating in Brisbane) about 3 years ago, and cut the bills by a huge chunk - even adding on a gas stove top and a gas convection room heater for the Brisbane 'winter' we spend $15 a month on mains gas. We never run out of water. I can put the washing machine on, then put the dishwasher on, then turn on the taps and still not get any complaints from the wife in the shower.

I just went down the instant road on my renovation - which after doing the sums seemed to make the most sense for me energy wise. I chose the Rinnai Infinity 26, which cost me $1150.

What I hadn't factored into the equation is some thieving mongrel stealing it from my wall last night. We are at the tail end of what has been a 14 month project on my first home that I have done as much as humanly possible myself to save on costs and about 3 weeks from moving in, baby on the way and some low life goes and does that. It makes my blood boil to think that you bust your ???? to try and get ahead and social scum come along and do that. Victoria Police's finest were completely disinterested and claimed that it was a common occurance.

So, for anyone who does install one of these - make sure that it is not easily accessible, otherwise you will end up paying more than you bargained for.

The Bitter and Twisted One.

I have heard this is coming quite common. I have installed mine low so that it is less visible. They would be pretty easy to remove in most instances. You might be able to buy it back of e-bay in a week or so?? :)

I've seen people put steel cages over them dynabolted to the wall so that they can't be nicked. It must be common enough.

HappyHammer, what's it like to have air conditioning? One benefit of global warming is that us Melbournians are still having beautiful 20 degree days in May!!!!
As for the theft issue, such things are often stolen by dodgy tradesmen (can't see some desperate drug user knicking a HWS for cash (crime) converters!!) so watch out for offers on certian items that seem to good to be true. Here in Melbourne there is often thefts from newly built places, sometimes they remove all appliances in the place. Many places are putting on security to ensure this doesn't happen.
Also guy who installed my ducted gas heater said to be careful putting it where it can be seen as they often get nicked as well.
Cheers
McBlurter

McB,

I only use A/C a handful of times a year, I live in the most temperate region on the East Coast, rarely too hot or too cold.:U :U

HH.

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Originally Posted by OBBob

I've noticed a new trend on a few houses lately, which is to have mutiple instant HWS's.

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That's a neat idea!

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I guess to reduce the distance the water needs to travel in the pipes. They might have one near each bathroom or kitchen / bathroom if there is a distance between them.

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I doubt that. It is more likely that they can utilise SMALLER heaters and consequently less gas for the immediate need of the location, eg kitchen/bathroom etc.

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I guess in the scheme of things if building a new place it isn't a lot more money and I imagine you would lose quite a lot of heat from even the insulated pipes ... not to mention all the cold water watsed waiting for the warm to come through.

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There is VERY little water wasted waiting for the heater to instantly heat the water. The water flow is restricted slightly to enable the water in the water jacket to heat. The water would begin to heat within the first litre of water. The "rest" of the cold water "wasted" is that water that sits in the HW pipe between the heater and the HW tap AND THIS applies exactly the same way to storage HWS.

BTW I used to (in another life :) ) service and repair instananeous gas HWS.

Yeah ... good point. I hadn't considered having multiple smaller units. Not a bad idea if you can get gas to each of locations without too much expense.

Wish I had have considered that for mine as I have a bathroom on each side of teh hosue and the gas pipe runs right past each.

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Wish I had have considered that for mine

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Gas was out for us because we're on bottled gas but we thought about a small storage heater under the kitchen. In the end, we decided against it because of the cost and the extra electricity we'd be using, but it would be a much better idea with instant. Will be putting in an Enviro Save when his flick mixer rig is ready for market.

And I'm so glad to meet someone who knows it's "had have" not "had of". :wink: