Which hot water unit?

[E Walde]

G’day all. I am building in Chittering, Western Australia and would appreciate some advice which hot water unit would be best for me. Sorry to ask as I’m sure you all get this question every day. The usual cunundrum, gas or elec. Storage or instant. Solar? There are two bathrooms for my wife, three kids (girls so multiply shower time by 3) and myself. We are using rainwater and a pump as out only water source, and bottled LPG and electricity for power. I have been told not to use the LPG as a fuel for the hot water unit as I will be changing bottles all of the time. I like the sound of instantanious as we would not be keeping a huge amount of water hot 24 hours a day as with storage (remember, three girls). Would that be a correct asumption? Any advise would be greatly appreciated.
Thanks in advance,
Scott.

[SelgasParticipant]

Don’t know much about Solar units so that one is out for me – one of the other boys may advise you better on that than I can. However if you are thinking of using gas then yes I can help. I would be looking at installing a 26 litre Rinnai Infinity or a 25 litre Bosch Electronic unit – either of these two are just fine. I would because you are using LPG as a fuel request that you fit a temperature control pad from the water heater so you do not have to waste energy heating the water up to 50 degrees then cooling it down again in the shower by adding or mixing cold water with it. The use of controllers will ensure you maximise the savings by being able to control temperatures to the levels you need which in turn will control just how much the gas valve opens and how much gas you will use. All instantaneous gas water heater no matter what make or model work on the principal of their size i.e. 20, 24, 26 etc litres/minute at a 25 degrees C temperature rise from the inlet cold water temperature, meaning if you want higher temperture water than the 25 degree rise the heater will slow the flow down to allow more energy to be applied to the flowing water so, at say a 15 degree inlet temperature and a specified outlet temperature of 40 dgrees you would have a full flow situation but when you step up the temperature to say 50 dgrees the heater will slow the flow down a little as I said earlier.
Here in NZ a bank of 2 45kg cylinders will last the average family using one of these water heaters about 6 to 8 weeks depending on the temperature of the water they require – higher temp = more gas usage.
Hope this helps.

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians

[Robert Stephen MortonParticipant]

Scotty. excuse peter for he comes from a place where the sun does’nt shine & the inhabitants smell like sulphur so they have to love sheep.
A 26 litre infinity will set you back in the order of $1300.00
A 330l rinnai solar system will cost you about $3200.00
you will get aprox $806.00 back from the Federal Govt for the REC’s making the cost to you about $2600.00
The Solar will be aprox $1300.00 dearer than the gas in the first instance, however with free hot water for the next 15-20 years (expected life of HWS) the $1300.00 would equate to aprox $65-$95 / year – I believe that gas or any fuel will cost you much more & possibly $1300.00 over 2-3 years
If you go for a solar system with a steel cylinder then the cost will be possibly $600.00 cheeper but they are generally only 260 litres and will have an expected life of 10-15 years. Recs are also only aprox $750.00
Bob

[ScottyParticipant]

Thanks heaps for your replies Peter and Bob. It sounds like you two are old sparing partners….
Free water sounds great, but I guess I would need a booster for when the sun is not shining (rare). Do most systems come with a booster built in, or would I still have to buy an elec. instantanious to heat the water on cold days. I guess the solar vs. Electric instantanious cunundrum comes down to the up front cost of solar compared to the cheaper price, but higher ongoing cost of electric.
Thanks heaps for narrowing down my options. The thought of changing my gas cylinders every 8 weeks does not really appeal to me, so I guess that’s ruled that out.
All the best to you both,
Scotty.

[Robert Stephen MortonParticipant]

Scotty, AS 3500 requires that water in a hot water service must be kept at above 60deg to stop the growth of legionella bacteria, therefore all solar hws must be boosted by electricity or gas, however the ammount of times the booster would cut in would be negligable.
And yes they come with an electric element or you install a gas booster on the hot water outlet. (quite expensive)

Bob

» This message has been edited by Robert Stephen Morton on 31 March 2006

[ScottyParticipant]

Looks like solar would suit me best. Thanks heaps for taking the time to reply.
All the best,
Scotty.

[SelgasParticipant]

Robert

Just as well I am thick skinned huh old buddy else I might think you are taking the piss outa me dam I just luv this Kiwi Auzzie bashin hehehehehe.

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians

[Robert Stephen MortonParticipant]

Hey Pete do you have to wear steel cap gummies over there ??? for work that is, I reckon that ordinary gummies would do for dancing & formal occasions.

Bob

[SelgasParticipant]

Rob

Nope steel toed gummies are a way too heavy to run in when you are trying to catch one of our cuddly and cute sheep, ya see ya need to stick their back feet inside yer gummies to hold em still and face them to the edge of a cliff so they kinda back into ya!!!
But hey it sure beats luvin one of them dern ugly skippy’s you folks are a kin too huh?? hehehehe

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians

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