Paul,

You are correct to a degree about the 55C temperature in HW tank, one does not know if it will reach it unless a temperature gauge is employed.

But one can oversize the solar array, in this case using more tubes, e.g. 30 instead of 22, which is the normal number for a 250L tank, plus set the collector's angle higher, that means optimize it for winter, the summer solar gain is more that ample to cater for the mismatch, especially in SA (in my case Barossa).

Even if the booster element is turned on in winter it will be a more cost effective solution than the heat pump, heat pumps do not use the J tariff, as you know they are fridges in reverse and turn on and off all the time, unlike the electric booster coming on only at preset time.

Anyway, in David's case your suggestion makes a lot of sense.

And to answer Aaron's remark, yes I did have such an assessment firsthand.

Regards

Stan

Thanks for what is a good article. My assessor did a good job when assessing our passive solar home but his most frequent comment was: the software doesn't recognise this or that innovation. For example, our top-loading washing machine recycles the first load - that's the water with all the washing powder in it. Because it's not a front loader, the software isn't able to record our recycling of water and washing powder from the top loader. Another example, our house is double brick and wall insulation is simply not possible, yet our assessment report recommended that we spend some of the Green Loan money we were entitled to borrow on wall insulation!
Overall, the ideas behind this scheme are OK but the bureaucracy that put it into effect imposed too many constraints or software limitations. If it was run by people who really understood energy and water efficiency and the practicalities of the problems people face, then it could have been so much better. Maybe it's not too late to ask ATA to run it.

DEWHA staff should have ALERTED PETER GARRET:
It is hard to believe that such a debacle has resulted from the headlong desire of the Federal ALP Government to tackle climate change in an exemplary manner before the world. But it is not surprising. That headlong thrust was not accompanied with adequate training, organisation and inspection processes. It is probable that the future of Government is in Federal unitarian local governments, and this would mean that the Federal will should or could be strengthened at the local level by officials of that Federal node.
In this case, DEWHA staff should have alerted Peter Garrett much more emphatically. But let us ask, 'was the pace of roll-out too fast for even DEWHA ground workers?"

DEWHA should GO FOR WOOL BATTS
DEWHA, under Peter Garrett and now with Greg Combe, should have gone for WOOL BATTS and should definitely do so now. They are the best for insulation; they are non-synthetic; they are non-conducting; and their use would give the wool industry a tremendous shot in the arm.

But it is important that the pace of installation be capped so that the race to get the rebate does not pressurize the industry beyond its capacity.

It is the suspicion of some here in the Katoomba electorate that the Aluminium industry is guilty of lobbying Peter Garrett or DEWHA so that this crude, old fashioned method of insulation is used to the detraction of wool batts. A local elector here says:
"If I pay for you to put in aluminium insulation, and it turns out to be faulty, am I to blame? NO! It is the manufacturer's fault.

However, I did point out that Peter Garrett, as then-the-full Minister of Environment, was sorely lacking if he did not get warnings from his department that installation was being buggered at the fundamental level of workmanship. -Bluey Quilty, MA(Australian History)
Advocate of Federal Unitarian government
ALP Branch member, Katoomba, NSW

Let's get back to "your" problem with the heat pumps. I actually did my homework. I could afford a heat pump, for which I had to outlay $2300, but I could not find the extra outlay for a solar system, even though the running costs are minimal and the rebate was greater. Incidentally, I am still waiting for the rebate.

Now let us get down to the operation of the heat pump. As installed, it is connected to the power continuously. That is because in an average household it does not have the capacity to supply enough hot water if the time is restricted. In my particular case, there are only two of us, we live in the country and have to provide our own water supply. We do not shower every day and we are frugal with our use of water generally. Our heat pump is therefore able to run for somewhat less than six hours a day, if it is run during daylight hours when the outside air temperature is warm. If it were to run during the night when the air temperature is much colder, not only would it run for much longer, the lower night rate tariff would not make up for the extra power consumed. If I turn the power on at 8.00 a.m., it generally turns itself off at around 2.00 p.m.

I believe that the next generation of heat pumps will be even more efficient, because the heating unit will be able to be installed in the ceiling, where the air temperature is much higher. Even so, our heat pump uses only about thirty percent of the power of an element type unit.

So there you go, don't knock the heat pump, and don't forget that there is also an environmental cost in actually manufacturing all your solar panels too.

David