# Forum Home Renovation Heating & Cooling  Off peak HWS V Heat Pump HWS

## lazydays

Lots of knowledgeable people on this subject so here goes. 
What is so bad with my Off peak HWS service that the govt tells me I should take it to the dump and replace it with a $4,000 Heat Pump system. 
I've just had my Green loan Assessment done and the recommendation is to replace it. 
The current system is a Hardie Dux 400L off peak tank and looking over the last years electricity bills it has averaged a usage of 8kw/day with an average quarterly bill of usually under $50. That seems fairly good for a household of 3 adults/ 3 teenagers and the occasional bath for some youngsters and it has NEVER run of hot water. 
At the time of building the house the budget got a bit tight and although I wanted to go with Solar, it was about $3,500 versus about $700. 
A quick search of google on heat pumps gives roughly a 250L system for around $4,000.
The Rheem gets shocking reviews on performance and noise and most of the specs of the others gives a noise level of 50db. Power usage on the specs says 1.2kw. But on what? Per hour? per day?? If per hour, how many hours per day must I multiply this by??? As stated my current system uses 8kw per day on the cheap offpeak rate of currently 6.99c/kWh. 
Thanks 
PS...location is SEQld

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## m6sports

i run my heatpump on Off Peak 1 and my power bill has drop from $40 every 3 months to $15. Thats a huge drop in KWh, which is good for my pocket and and enviroment  
i replaced mine for a heatpump due to needing a new hot water heater as the old one was on its last legs. With all the rebates at the time it cost me less to install the heatpump then to replace it with a normal heater, so it was a no brainer  :2thumbsup:

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## GeoffW1

Hi, 
Subsidies and grants supposedly bring the cost of a heat pump down to about the same level as an off-peak HWS.  
I get a feeling it is the same as a cash-back offer on a  **  brand laptop, you spend more effort trying to get your refund than than it is worth in the first place. 
You are correct, heat pumps in general have had some very bad reviews for efficiency and reliability, so I wonder if the engineering has a way to go yet. 
One thing worth keeping an eye on is when, in your State, mains electricity HWS (whether intended for off-peak use or not) will be withdrawn from sale. In Qld already they cannot be used for replacement where gas is available, and in new houses are banned from this year everywhere. 
If you have a HWS older than about 10 years (as I do) a decision of some sort is needed this year. 
Cheers

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## woodbe

> What is so bad with my Off peak HWS service that the govt tells me I should take it to the dump and replace it with a $4,000 Heat Pump system.

  When your Off peak HWS turns on, it runs a resistance heating element in the water tank. For every Kw of power consumed, it generates a Kw of heat in the tank.  
When a heatpump HWS turns on, it runs a heat transfer compressor cycle system (like a fridge in reverse). For every Kw of power consumed, it generates about 3Kw of heat in the tank. 
Assuming you connect it to the same rate power, it will shred your power bill. Ours dropped from $3-400 per year, to less than $100 per year. 
In Qld, you should look seriously at Gas boosted Solar HWS. If you cannot get Gas, then electric boosted on offpeak/demand tarrif. 
woodbe.

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## Bloss

:What he said:  sort of! An efficient heat pump HWS in the right climate (like Gold Coast) will have a COP (Coefficient of Performance) of from 4-5 (at an ambient temp of 30) not 3 (which is what roughly what an A/C does). What that means is that for every kW of electricity in it gives the equivalent output to heat your hot water is 4-5kW. So you do not compare the kW energy in between a heat pump and the existing electric or offpeak - but the heating capacity and then heat pumps wins. 
But as Woodbe said Qld Solar HWS performs exceptionally well and if you have gas then that is the most efficient boost - if not then electric boost (most cannot be boosted using off-peak tariff - utility will not allow that connection). The many I know who have solar HWS in Qld have almost no bills for boosting - but size the tank correctly and add extra insulation to it to.  :2thumbsup:

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## lazydays

thanks for the replies. it seems logical that solar is the way to go here.
I'll start investigating sizes and prices.
I don't have access to gas boost. I suppose since they will not allow power boost off my night time rate then the same will apply to my "controlled rate' which I run the pool pump on?

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## woodbe

> I suppose since they will not allow power boost off my night time rate then the same will apply to my "controlled rate' which I run the pool pump on?

  That's the demand tariff I was mentioning. It gets turned on off according to availability of power - if the load is high that day, you get cut, and for the privilege, the cost is lower. 
I dunno if you can use it with boost. Ask. We don't get it here (yet) 
woodbe.

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## Bloss

:What he said:  The tariff that you will be allowed to connect boost to will depend on the utility, but also they will often have different options based on the configuration of the boost switch too. So as woodbe says - check with them.  :2thumbsup:

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## Smurf

If you're just going to "install and forget" as I think most will do (apart from solar fanatics etc) then a quality heat pump will save around 70% compared to a conventional electric HWS just about anywhere in Australia. It will work a little better in Brisbane than in Hobart, but there's not a huge difference - perhaps 65% versus 75% at the extremes. 
Solar is more complicated in that you need to get it "right" or it won't deliver the promised savings. That said, for a commercial "off the shelf" system left to run it self (no fiddling with the boost - just letting it run itself) you can achieve 45% to over 95% saving on energy consumption as long as it's a properly sized and installed system.  
In theory, you can increase the saving by manually operating the booster but to be honeset I can't see the vast majority of households doing that. Those with an interest might, and they are generally the people who bought solar HWS years ago. But the rest will, in my opinion, just put it on the roof and forget about it unless something goes wrong, at which point they'll call a plumber. Hence I base all comparissons of hot water on the assumption that solar boosting is fully automatic with no manual intervention. 
Which is best varies around the country and with your individual situation. Heat pumps can be installed in most homes whereas solar doesn't suit all situations. Gas isn't available everywhere, and in some areas it's prohibitively expensive anyway. 
As for the off-peak connection for boosting or to run a heat pump, I've never heard of any problems for a "normal" connection in Qld, SA, WA or Tas. Check carefully in the other states. 
Some heat pumps, eg Siddons, are specifically intended to be on off-peak as are some solar HWS. Sure, you could run it on day rate power but that's expensive now and will become moreso as interval metering is rolled out. There's no point switching to solar only to end up with higher bills than you had before (a fairly common outcome). So either boost with gas or get one that can boost on limited hours electricity supply, either the official "off peak" or via your own timer once interval metering is rolled out.  
As for specific products, I'll only comment for heat pumps as their are far too many solar HWS on the market to evaluate them all. I'll just say that the very easy way to spot duds is to identify those with a boost element. It's certainly not needed in most parts of Tasmania so shouldn't be needed in the warmer states unless you really are up in the mountains or well inland and getting regular snow / ice. A quality system certainly doesn't need a booster in suburban Sydney, Melbourne, Adelaide etc.

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## Solarman

There are good heat pumps and there are bad heat pumps . . .  you only need to read some of the various other blogsites around, and there are common remarks on the bad ones, so I'm not going to mention any names!
We have been selling heat pumps for about 7 years - we've collected a bit of data on them and done a comparison with the popular ones with ours at Comparing our domestic 264/327 heat pump with other brands 
8kw per day on off-peak is not very much for 6 people, are you sure there isn't a daytime booster (second heating element) ? Most 6 person households would use double that. Anyway, our heat pump reduces electricity consumption by around 80% not much reduction for you personally, but nationally thats a lot of electricity! 
The Queensland Solar Hot Water Rebate Scheme (incl Fed Rebate) plus the federal RECs scheme ensures that the overall replacement cost will be minimal.  
These rebate schemes may not be around much longer as the take-up of the PV rebate was hugely underestimated (which is why they cut it off early) so do it now! :2thumbsup:

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## Black Cat

If you are thinking solar, then don't forget to have a look at Panels VS evacuated tubes. The tubes give you a longer collection period if your roof is facing the right way, so may be an attractive option for you.

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## Smurf

> There are good heat pumps and there are bad heat pumps . . . you only need to read some of the various other blogsites around, and there are common remarks on the bad ones, so I'm not going to mention any names!

  Same goes for heating houses (space heating) with heat pumps. Some work perfectly well in Tasmania in the middle of Winter but others struggle in warmer climates such as Sydney. 
Bottom line is that a quality heat pump can save 70%+ on your heating and hot water electricity use. And yes it can run on off-peak in the case of hot water. But there's plenty of dodgy systems around that fail under cold conditions, are far less efficient than is easily possible, are noisy or otherwise dissapoint consumers. 
Personally I like the Siddons units for hot water and quality air-condioners such as Panasonic, Mitsubishi etc for space heating use. Interestingly, it's the really biggest selling air-conditioner brands "Australia's favourite...." that don't work in the middle of Winter and have too many breakdowns. And it's the big name hot water companies that rely on back-up booster elements, don't work on off-peak, noisy etc. 
The Siddons unit I installed in December is working fine so far. I'll be interested to see how efficiency goes over Winter, but I'm not expecting any real issues apart from a modest increase in power use (still way below what a conventional electric HWS would use).

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## lazydays

[quote=Solarman;788511
8kw per day on off-peak is not very much for 6 people, are you sure there isn't a daytime booster (second heating element) ? Most 6 person households would use double that. [/quote]
No booster at all. It's 100% off peak. No other way it could possibly run. 
Thanks for further food for thought.

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## Bloss

Not sure what some of the figures being used here mean, but worth clarifying into lay terms:  
kW is kilowatt (unit of energy) and refers to capacity or size eg: a 3.6kW element or a 2.7kW A/C unit. 
kWh (or kWhr) is kilowatt hour and is the amount energy produced or consumed over time so a 1kW radiator run for an hour = 1kWh - and that's what is charged for by utilities. 
Average household in Australia use around 6000 to 8000 kWh annually ie: 17-22kWh a day of which around 5-7kWh (~30%) will be to get hot water. 
One of the reasons to move away from electricity of any type to solar or gas is that while electricity is around 26% of household energy use it emits around 50% of all greenhouse gas emissions. (we use fossil fuels, mainly coal,  very inefficiently). 
Eventually energy pricing will accurately reflect that fact - it doesn't yet, not even close. That will then change the relative pricing of the HWS we buy. Right now we are doing it like we do with PC printers - we get a really cheap printer, but the consumables are dear and worse it is as though we buy the cartridge refills, but are not paying the real price for the ink and the container - (in the case of electricity we do not pay proportionately or at all really for the damage the carbon impact has on the environment - and that affects everyone - even those who use little  no electricity). 
On me bike now . . .  :Smilie:

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