Instant v stoarge Howt water service

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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. :)