Thread: EV general discussion

Originally Posted by DiscoMick

Yep, once you have solar, the trick is to move consumption to the daytime and minimise night time demand.
We have solar hot water, so that's daytime.
With hindsight, we would have been better to have installed a heat pump and spent the extra money on more solar to power it.
You learn with time.

That all depends on what solar hot water you go for. Something like an Apricus will heat from the sun for 8-9 months of the year down south with no need to boost it unless the weather is really bad for a long period of time

As my off peak 350l Rheem is now 15 years old, I recently did a bit of a cost benefit analysis.

It costs about $40 a quarter to run the Rheem and a new one will cost about $1k.
So I am looking at alternatives.
My house cannot use solar hot water as for 6 months of the year it is completely in shade and 12 months shaded by neighbour's trees.

I recently did the an exercise on using an LPG instantaneous using manufacturer numbers, and 15 minutes per day and it would cost roughly $1000 per year to run one!!!!!! Almost 10 times the cost of the off peak.

Now maybe off peak will not exist in a few years time, but how long I do not know.

I guess some form of instantaneous electric is the go. I read about a Flash heat unit produced in Melbourne some time ago but nothing since.
The capital cost was high but operating cost low.

I have rejected the idea of a heat pump due to the complication, noise, and poor reliability. I recall about 10-15 years ago the commonwealth Government paid for multiple units in Caravan Parks etc. I remember at Cape Hillsborough they had about 8 of them and only one or two were working at a time. A colossal waste of money.

So what is the best instantaneous to get. I have usually very small demand using it only for one shpower a day. My Diswasher has it's own heater, but sometimes we have guests and the second bathroom is used, and what about the sink?
I just hope I get another 5 years from my off peak.
Regards PhilipA

Originally Posted by PhilipA

As my off peak 350l Rheem is now 15 years old, I recently did a bit of a cost benefit analysis.

It costs about $40 a quarter to run the Rheem and a new one will cost about $1k.
So I am looking at alternatives.
My house cannot use solar hot water as for 6 months of the year it is completely in shade and 12 months shaded by neighbour's trees.

I recently did the an exercise on using an LPG instantaneous using manufacturer numbers, and 15 minutes per day and it would cost roughly $1000 per year to run one!!!!!! Almost 10 times the cost of the off peak.

Now maybe off peak will not exist in a few years time, but how long I do not know.

I guess some form of instantaneous electric is the go. I read about a Flash heat unit produced in Melbourne some time ago but nothing since.
The capital cost was high but operating cost low.

I have rejected the idea of a heat pump due to the complication, noise, and poor reliability. I recall about 10-15 years ago the commonwealth Government paid for multiple units in Caravan Parks etc. I remember at Cape Hillsborough they had about 8 of them and only one or two were working at a time. A colossal waste of money.

So what is the best instantaneous to get. I have usually very small demand using it only for one shower a day. My Diswasher has it's own heater, but sometimes we have guests and the second bathroom is used, and what about the sink?
I just hope I get another 5 years from my off peak.
Regards PhilipA

I have sanden heat pumps for heating hot water and hydronic heating. They are both great and a PITA. The PITA is the person selling them to do more than Sanden designed each for. I have multiple into two tanks. Sandan is One heat pump to one tank. Mine are working easily heating the house and also ever ending hot water IF I cannot chase the kids out of the shower!!

The noise of the 5 Sanden heat pumps is a lot less that our fridge. The heat pumps out side can not be heard inside at all- The fridge is humming in my ear now. My nephew got a cheap heat pump installed a year ago. Suspect his might not have the reliability and it is louder and not as efficient as mine.

For your use I appreciate the higher initial cost might not see cost recovery as quickly as mine was.

Sanden Hot Water Heat Pumps - Energy Efficient Hot Water Systems


6 year warranty on Heat pump and 15 on tank - Suspect the heat pump is very similar to all the better quality spit systems. They are basically the same technology.

Back on EVs. The marathon accompanied by a Toyota FCEV yesterday and today was very cool. A lot cooler than the runners.

I did consider GAS several years ago before deciding on the Heat pumps. A family member who works in electricity and gas had predicted the issue with gas occurring now. While off peak electricity is not guarantees; We know for a fact peaks and troughs in both supply and demand for electricity has been used by industry and others to take and use the cheap power when it is available. Suspect that will become more common not less common with changes allowing feeding surge pricing to meet high demand periods already in place or planing.
The gas news OS is interesting

"Natural gas, used to generate electricity and heat homes, was abundant and cheap during much of the last decade amid a boom in supply from the U.S. to Australia. That came crashing to a halt this year as demand drastically outpaced new supply. European gas rates reached a record this week, while deliveries of the liquefied fuel to Asia are near an all-time high for this time of year."
The Era of Cheap Natural Gas Ends as Prices Surge by 1,000%

Originally Posted by PhilipA

I have rejected the idea of a heat pump due to the complication, noise, and poor reliability. I recall about 10-15 years ago the commonwealth Government paid for multiple units in Caravan Parks etc. I remember at Cape Hillsborough they had about 8 of them and only one or two were working at a time. A colossal waste of money.

I can beat that,we went to a commercial site about 6 weeks ago,11 out of 12 were not working,luckily they had gas HWS as backup.
PCB's,compresser capaciters,sensors,defrost solenoids the usual culprits,with the occasional faulty compressor and refrigerant leaks, as well.

There is another commercial site we havent got to yet that has 6 out of 6 not going,also with gas backup.

The gas will trip out when the power goes off,and when the building goes into fire mode,and has to be manually reset,as per regs,so they soon know when the back up HWS doesnt work.

Have never worked on a Sanden,seems they are on Co2,so will operate at huge pressures.
If they operate same sort of tech as split systems,with inverter compressers,numerous PCB's,etc,no doubt repair costs will be extremely expensive,and may not be viable to repair,same as most wall split system AC units.
Hopefully parts are in stock,one wouldnt want to be waiting 6 weeks.
Good they have a 6yr warranty and a pro rata of 15 and seems they are pretty efficient going by the data.

I wonder what sort of cost are they installed, compared to an equivalent electric HWS?

They are a bit like EVs,will suit some but not others.

Originally Posted by scarry

I can beat that,we went to a commercial site about 6 weeks ago,11 out of 12 were not working,luckily they had gas HWS as backup.
PCB's,compresser capaciters,sensors,defrost solenoids the usual culprits,with the occasional faulty compressor and refrigerant leaks, as well.

There is another commercial site we havent got to yet that has 6 out of 6 not going,also with gas backup.

The gas will trip out when the power goes off,and when the building goes into fire mode,and has to be manually reset,as per regs,so they soon know when the back up HWS doesnt work.

Have never worked on a Sanden,seems they are on Co2,so will operate at huge pressures.
If they operate same sort of tech as split systems,with inverter compressers,numerous PCB's,etc,no doubt repair costs will be extremely expensive,and may not be viable to repair,same as most wall split system AC units.
Hopefully parts are in stock,one wouldnt want to be waiting 6 weeks.
Good they have a 6yr warranty and a pro rata of 15 and seems they are pretty efficient going by the data.

I wonder what sort of cost are they installed, compared to an equivalent electric HWS?

They are a bit like EVs,will suit some but not others.

Frost are a possible No No for heat pumps- the put out a lot of very cold air. If it is already at or close to zero ice can form on the Heat pump fan. Just onces here but frosts are very rare and location very good. It is a issue to be aware of.

Originally Posted by NavyDiver

Frost are a possible No No for heat pumps- the put out a lot of very cold air. If it is already at or close to zero ice can form on the Heat pump fan. Just onces here but frosts are very rare and location very good. It is a issue to be aware of.

The ones i have seen have a de ice cycle to keep the frost off the evaporator,similar to an AC.
Ice on the evap will definitely reduce capacity.

Rare for frosts here in Brisbane,anyway,but we do get them on occasions.

I think Rick130 has worked on some in the Hunter Valley,i presume frosts would be pretty common there.

Talking about them putting out a lot of cold air,i know where there are 8 huge commercial units in a plant room in a commercial building,the consultant on that job obviously had no idea.

A few months later three large exhaust fans were fitted to the plant room,but they still had issues with condensation on the ductwork and plant room walls and floors.

Edit Sort of defeates the purpose,use HW Heat pumps,then have three huge fans running and wasting power to keep them operating.

I had a heat pump HWS in Yass (same climate as Canberra) for several years. It performed faultlessly.
I now have a had one in Tuross Head for several years and it has also been faultless and convenient. If I know I am going to be away for a week or so, I turn it off at the meter box. If I return by about sunset and switch it on there is enough hot water for a couple of showers by bedtime.
I know that in some commercial applications people have had problems, but I have no complaints.

Have a read on the MyEfficient Electric House Facebook group - lots of very experienced professionals plus thousands of householders very happy with better quality heat pump HWS (Sanden and Reclaim mostly).

But with reduced solar FIT and solar systems cheaper now, a normal resistive electric HWS may be cheaper to run and much more reliable?

Or if you have 3 phase an instantaneous Steibel maybe the go for low usage.