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  1. #1
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    Default Heat Pump suggestions

    We are looking at replacing the HWS. Looking possibly at evacuated tubes, but also at heat pumps. One thing that attracts me a bit to heat pumps is that in the future we will not be able to claim any rebates for replacement, so although cost now isn't a big factor due to the rebates making all of them relatively OK, the future replacement cost will be a fair bit more for evacuated tubes. Only problem is that the current HWS has an aircon mounted above it. From memory clearance from the ground is about 1760mm, and the recommended heat pumps wont fit (315L or so Steibel or Siddons). DOes anyone know of a reliable unit that is lower? If not, then how much is it likely to cost in extra installation cost to move the HWS by about 5m or so?

    Peter
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  2. #2
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    Siddons sell pre-charged refrigerant coupling hoses to move the compressor further away from the tank if that's what you are asking about? They came in 1.5m, 3m, 5m and 7m. when we bought ours a couple of years ago.

    I would have thought solar was the way to go in Brisbane though. Running costs should be less than heatpump even if long term replacement is higher (which also surprises me)

    Life of either system should be long though, and relative costs will probably be different by then...

    woodbe.

  3. #3
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    In my case it's the tank location that's the problem - the Siddons tank is 1900m or so high. The location of all the inlet and outlet plumbing is under an aircon unit which is 1760mm above the gound, so the tank won't fit where the plumbing is located. From what we have seen, running costs certainly should be lower in Brissie, but from whatI can work out, the cost of an unrebated system is about $8000 for evacuated tubes, and about $4000 - $5000 for a heat pump. On that cold middle winter day (on a weekend too is my past experience) when the system finally dies, I expect that $4000 will be easier to find for an emergency replacement than $8000. Are you saying that you expect the relative cost to be about the same for system replacement in the future?

    Peter
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    Quote Originally Posted by petersemple View Post
    Are you saying that you expect the relative cost to be about the same for system replacement in the future?

    Peter
    Hi Peter,

    Not really, just that they will be different to what they are today. Perhaps cheaper.

    Bear in mind that when the Siddons dies, you're up for standard compressor repairs or replacement - its servicable for a long time into the future. Likewise, Evac tubes are replaceable leaving the water circulation system untouched. Should last a long time...

    By then, I'd expect replacements to be higher efficiency and cheaper than today, and I'd also expect that by then we would be permitted another run at the RECS for the replacement system.

    Bottom line for me, I would buy the system that will deliver the lowest running costs for my needs now and not worry about replacement - you will be able to decide that when the time comes based on the available technology and price. You can always swap to the other system at replacement time if it has gained an edge on the competition.

    woodbe.

  5. #5
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    Heat pump systems can be had where the tank is remote from the heat exchanger - so they aren't as tall.

    Unrebated solar is only expensive precisely because there are rebates. It is called market distortion.

    Mind you where you got the $8K figure from is of concern - Runonsun will sell you a 250 litre electric boost system for $5200 before rebates. Even with a $1500 install that's still a grand cheaper than your quote. Reduce that by the $3400 in QLD rebates and RECS.....
    Joined RF in 2006...Resigned in 2020.

  6. #6
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    Where I got the $8000 figure is mostly in my head ) It is a ballpark of what we have been quoted for evac tubes from memory (none of the quotes are in front of me). With rebates thay come down to about $3500 - $4000 out of pocket. Just looked at runonsun. Their biggest system is 250L. Everything we have told is that we need bigger for our family. Maybe we've been told wrong. Also, I am not putting a tank on the roof. Too many people I know have ended up with water damage inside the house when the tank starts to leak (I guess water goes down the piping, because I assume any leak that falls directly on the roof wouldn't be a problem or we'd all be in trouble when it rains).

    Peter
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  7. #7
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    The choices are replace with same, with heat pump, or with solar (either evac tube or flat panel).

    The general consensus is that evac tubes make more sense in southern latitudes and in higher altitudes.

    Brisbane is neither, so get quotes on flat panel systems as well.

    The first thing to understand about selecting a solar HWS is the draw down factor - what you and your family require in hot water needs for AT LEAST two days (pref 3).

    This means an opportnuity exists to FIRST reduce your hot water consumption BEFORE you look at 'sizing' a tank and SHWS.

    Here's how it works. A modest, energy and water efficient shower is one that lasts not more than 10mins and is run thru a 9L/min 3-star WELS-rated shower head (less flow rate is a joke).

    With this shower head in place, a 10min shower uses 90L, of which approx 50L is hot water. Multiply by the number of showers per day X 2 and this is the size of the tank you will require, in order to get the benefit of the sun-heated HW.

    Further to this, you need to leave the booster switched off so you can manually control when you need to boost, otherwise it will automatically boost each night so the tank will be full of hot water when the sun peeps over the horizon each morning. Operating in 'auto-pilot' what you have is actually an Off-Peak HWS with a bit of sun-boosting, rather than the other way around.

    This is why hot water conservation and tank sizing is so crucial.

    Why can't you move the A/C unit, or, probably even easier, get the plumber to lengthen the existing pipes so the new tank can sit beside the A/C unit? This is what they are trained to do, after all.

  8. #8
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    ALright, looking more seriously at evac tubes. Can't really move the A/C unit. It's a small though the wall one, and we would be left with a huge hole in the wall to fill. Not what we want to do. Have heard a lot of people talk about flat panels as being a risk for leakage, and that a leak is usually expensive compared to evac tubes. One question is to do with the number of tubes. We have had 2 companies quote on the same system, but one quoted for 20 tubes and one for 30. How do we know how many to go with (the cheaper quote was for more tubes BTW - on the same system, same size tank, so that company gets the nod, but could we get it even cheaper if we ask them for 20 tubes instead?)

    Peter

    ETA - we already have 9L/min shower heads installed on all showers and usually have 4 min showers, we use a front load washing machine and generally do what we can to reduce water usage. Appliances are connected to cold water and we wash cold - again to reduce hot water usage.
    Life's too short for dull sandpaper

  9. #9
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    If you are handy you might look at a retrofit using evacuated tubes and a decent size newish tank that has been replaced with a solar HWS. See here: eBay Australia Shop - ultimate products direct:

    I have seen a few done now and have just got hold of a 400L tank to do one for me. No rebates at all but a good solar HWS for under $2K.

    I know one happy owner who has used this mob too: SolarVox :: Home I haven't decided who I'm gunna buy the tubes from. In a cold climate you need 58mm diameter tubes and either 1.8 or 2m long.
    Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.

  10. #10
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    Quote Originally Posted by Buzzman View Post
    Further to this, you need to leave the booster switched off so you can manually control when you need to boost, otherwise it will automatically boost each night so the tank will be full of hot water when the sun peeps over the horizon each morning. Operating in 'auto-pilot' what you have is actually an Off-Peak HWS with a bit of sun-boosting, rather than the other way around.
    This is what puts me off recommending solar HWS for the average residential situation. Yes you could operate the booster so as to maximise efficiency, but how many people are actually going to do that in practice over the long term? If people have difficulty switching their computer and washing machine off at the wall when not in use then I find it very hard to believe that they will actually operate the solar HWS efficiently.

    In contrast, put in a Siddons or other quality heat pump (beware some of the duds) and you can be confident that it will save 65 - 75% (depending on location) of the electricity otherwise consumed to heat water. No iffs or buts, it will save that amount of energy. The solar HWS may well be more efficient in theory, but how will it actually perform in practice with actual usage?

    I don't have figures for evacuated tubes or other locations, but back in the 1980's (the good ole days...) the Hydro-Electric Commission in Tasmania did some decent research into hot water usage (they put real time data loggers on houses with continuous tariff water heaters to gain the hourly usage data) as well as the performance of solar.

    The conclusion was that a conventional flat plate solar HWS (like the ones most commonly made by SolaHart) will save 45 - 50% of electricity consumption in a "set and forget" usage pattern with location in Tasmania.

    Part of the problem with solar being that hot water energy usage as measured was found to be 30% higher in Winter than in Summer, noting that in Winter in Tasmania the booster would be supplying the vast majority of the energy input. For this reason there was an obvious alternative option to install a wet back to a slow combustion wood heater (sales of combustion heaters without wet backs were booming at the time following the heating oil price hikes) as this would deliver a comparable benefit to solar for water heating.

    Combine both a wet back and solar and there would be virtually no need for an electric booster, assuming the fire was actually lit to heat the house during cool weather.

    In reality however, solar and wood hot water systems never gained significant market share in Tas prior to very recently. Cheap electricity and consumers focused on space heating as by far the largest energy user (and even greater cost given that before the wood heater boom of the 80's the usual means of space heating was oil-fired, the cost of which soared to ridiculous levels circa 1979) diverted any real attention away from solar hot water. It was only a handfull of, somewhat ironically, anti-Hydro greens who actually installed solar / wood water heaters and there are very few such systems still in use today.

    Now, I don't doubt that there will have been some improvements to ssolar hot water systems over the years but nothing I have seen demonstrates that there has been any major technological change in an "off the shelf" flat plate system. Anecdotal data supports that too. So I'd still expect it to save somewhere around 50% under Tasmanian conditions.

    The above leads me to recommend heat pumps for use in Tasmania, with solar being more suited to warmer climates. No messing about, the heat pump just sits there and delivers a 65% saving.

  11. #11
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    Well, we are going with an Apricus evacuated tube system. The booster is a manual switch that you have to turn on, but it turns off automatically when the water is hot enough. We used it on friday (the tank is in but they need to come back to do the roof collector. It's now Sunday and we haven't used the booster again. WHen it's all up there will be a readout of tank and roof temperatures as well apparently, to help judge if boosting is needed.

    Peter
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    That's a quality brand and should work well for you. In Brisbane you should rarely need boost.
    Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.

  13. #13
    Senior Member Bluegum's Avatar
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    Quote Originally Posted by petersemple View Post
    Well, we are going with an Apricus evacuated tube system. The booster is a manual switch that you have to turn on, but it turns off automatically when the water is hot enough. We used it on friday (the tank is in but they need to come back to do the roof collector. It's now Sunday and we haven't used the booster again. WHen it's all up there will be a readout of tank and roof temperatures as well apparently, to help judge if boosting is needed.

    Peter
    This is a great thread and thanks for the contributions from all concerned. We have been offered the Apricus system as part of the donations from them for flood affected people. I had a member of the master plumbers come by to give us a quote and he was suggesting the heat pump system was very effective and extremely cost effective. His comments were that the heat pump system would use about $150 per year. He thought the Apricus system was also an excellent unit but you had to take into account of the cost of running the pump to the unit on the roof and the the cost of boosting. Apricus felt the 315 litre tank with 30 tube heater would be more than suitable foe a family of three
    Dave,
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  14. #14
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    Quote Originally Posted by Bluegum View Post
    This is a great thread and thanks for the contributions from all concerned. We have been offered the Apricus system as part of the donations from them for flood affected people. I had a member of the master plumbers come by to give us a quote and he was suggesting the heat pump system was very effective and extremely cost effective. His comments were that the heat pump system would use about $150 per year. He thought the Apricus system was also an excellent unit but you had to take into account of the cost of running the pump to the unit on the roof and the the cost of boosting. Apricus felt the 315 litre tank with 30 tube heater would be more than suitable foe a family of three
    The 'cost of the pump' on a solar system is trivial and a BS argument - they run at between 40-75W (so about 20c a day if it ran all day!) and run only as needed by the temperature differences. In Ipswich the should be almost no boosting cost if a) the system is sized correctly and b) you know how a solar system works.

    That means not having any booster configured to keep boosting all through the night - or even at all except by a timer or manual switching (as well as the thermostat of course).

    It also means using most of your water first thing in the morning so the tank can heat up using the sun (so showers, washing, dishwasher etc in the morning if you can). Solar can't heat if the booster has already heated it overnight - the tank has to be cool in the morning for the solar tubes/panel to be most effective.

    You want a electric or gas boosted solar hot water system not a solar boosted electric or gas HWS!

    Power prices are heading up and will continue no matter how good your heat pump is. Solar energy will stay free!
    Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.

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    Quote Originally Posted by Bloss View Post
    Power prices are heading up and will continue no matter how good your heat pump is. Solar energy will stay free!
    What really matters is how much electricity (or gas) you actually end up using to meet your hot water needs. In terms of avoiding rises in costs, you want the lowest power consumption regardless of whether that is with solar or heat pump.

    Producing solar hot water isn't really the objective. The objective under most circumstances is minimising the use of electricity, in terms of the total amount used over a 12 month period. Heating water with the sun is just a means of achieving the objective of using less electricity.

    As for the pump for the solar, agreed that's a non-issue. It's in the category of not wanting to spend $1 in order to save $10, a very common situation unfortunately when it comes to energy efficiency in general.

  16. #16
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    Quote Originally Posted by Bluegum View Post
    This is a great thread and thanks for the contributions from all concerned. We have been offered the Apricus system as part of the donations from them for flood affected people. I had a member of the master plumbers come by to give us a quote and he was suggesting the heat pump system was very effective and extremely cost effective. His comments were that the heat pump system would use about $150 per year. He thought the Apricus system was also an excellent unit but you had to take into account of the cost of running the pump to the unit on the roof and the the cost of boosting. Apricus felt the 315 litre tank with 30 tube heater would be more than suitable foe a family of three
    Sounds like the exact system we have in. To give you some idea, like I said, the tank went in on Friday, and the solar collector was done the Monday after (yesterday). Because they weren't doing the collector until later, the tank was essentially still an electric HWS for the weekend. They turned on the booster on Friday lunchtime as they left, and we would just have to use it through the weekend as we needed to keep up the hot water (it's a push button switch that only goes on when we turn it on - not automatically over night or anything). Anyway, from Friday lunch we got through until Sunday night without using the booster. We had to use it on Sunday night to give us showers on Monday. Remember this is with no solar collector at all, so the 315L tank lasted a family of 5 in a big house for several days. I am guessing that this means good things for using the solar. One day (or even maybe part of a day) should be enough to give us several days hot water at a time. I don't imagine using the booster much.

    Peter
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    Quote Originally Posted by petersemple View Post
    Anyway, from Friday lunch we got through until Sunday night without using the booster.
    5 people, 315L and 2 days = 31.5L per person per day.

    And there's the rub. If you have done the work and installed water saving shower heads etc, and an energy saving mindset in the home, any investment you make in energy efficiency pays back double. Hats off to the Semple household!

    Sounds like a good solution.

    woodbe.

  18. #18
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    Quote Originally Posted by Smurf View Post
    Producing solar hot water isn't really the objective. The objective under most circumstances is minimising the use of electricity
    Aside from the fact of the continuing main heat source being free (the sun) and from an engineering viewpoint on using energy well (and in my case a certain obsessiveness about waste & inefficiency) electricity is only a concern if it is fossil fuel sourced (or uranium, for different reasons). If the energy supply is renewable (say being bought through Greenpower) then what does it matter. If the grid supply or your household is all renewable then even an electric resistance HWS is OK. There might be cheaper and more efficient HWS choice to be made, but the clean source makes the choices different. Of course the more wasteful we are in energy use the the more costly it will be for us all to have the increased generation capacity that waste creates - but that is then a financial cost issue not an environmental one.

    And in fact contrary to what you say none of us care about the energy at all really (except that it must all eventually be renewable) - we really want what it produces: we want hot water, we want warm houses, we want cool houses we want to use tools and electronics systems and on it goes. The energy equivalent or analogue we haven't yet cottoned onto is the one that is like what I want from a phone systems or the internet - I have a series of uses and things I want to do and really do not care who or what is in the middle of them or what the technology is - I want the service. Energy is the same we want the energy and the goods and services it produces and the over-riding need (and challenge) is to replace a system that uses a finite and filthy energy source to provide all those things with one that is effectively infinite and clean. Simple really!

    oops, raving again . . .
    Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.

  19. #19
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    I still maintain my view that the only reason for installing a solar water heater is to provide hot water using less, or no, electricity / gas.

    The motivation for using less electricity / gas will vary between individuals (cost, environment, physical lack of access to mains power) but achieving that lower (or no) use of it is still the only reason most people consider using solar.

    I stay in hotels every now and then either for holidays or work related travel. 90% of the time I would have no idea how the hot water is provided. I turn the tap on and hot water comes out. Hot water is hot water, unless I can see the water heater then I have no idea if it is gas, electric or whatever.

    The last hotel I stayed in? No idea how they heated water. Hot hot water came out the taps as expected so I had no reason to question anything to do with it. Same with most hotels I've ever stayed in. I remember noticing a large LPG tank and external gas HWS at one, and there was an electric cylinder in a cupboard in another. But hot water is hot water - if I hadn't see the means of heating it then I'd have no idea if it was electric, LPG or whatever.

    Most people just want hot water that works. They don't think about it unless it stops working, is costing a lot or, for some, due to concerns about human impact on the natural environment. Hot water is hot water whether it came from the sun, electric, gas, oil, a wood stove or whatever. It's the exact same end product - stay in a hotel and odds are you'll have no idea how they are heating the water.

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