Hot water cost double NZ average even with solar

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alaw005

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#3212885 1-Apr-2024 15:23

That makes sense. There is no non return value from top tank back to bottom. As noted expect that solar is drawing off hot water and having to then make up with element. Would it be better if element in top tank? And remove the pipe back to bottom tank?

tweake

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#3212891 1-Apr-2024 15:45

alaw005: That makes sense. There is no non return value from top tank back to bottom. As noted expect that solar is drawing off hot water and having to then make up with element. Would it be better if element in top tank? And remove the pipe back to bottom tank?

there has to be a non return valve, or you have the pipe layout mixed up. otherwise every time you turn a hot tap on, cold water will bypass the tanks and you get very cool "hot" water. just check that pipe doesn't go to a tempering valve (which is a common setup).

top element or bottom depends more on how the system is designed. if it was a big solar panel then use a top element for back up use. if small solar then use bottom element as main heat source with solar adding to that. personally i would disable the solar and see how the power bill changes.

alaw005

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#3212893 1-Apr-2024 15:57

I might have missed the non return valve. I will disable solar and see what happens. I had previously just turned pump to solar off but occurs to me now that I need to turn the solar valves off too. Then after a few days I will request info from Mercury on daily power consumption to see if any difference. Hopefully weather stays the same as good control. I only have two panels on the roof so expect that isn't enough other than just topping up so element on bottom makes sense.

Jase2985

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#3213125 2-Apr-2024 09:00

im wondering if the solar hasnt been working and you have been heating the tanks and the roof top array each night. The thermostat will probably be higher giving its a solar system so it could be heating to 70+ degrees.

10h x 2kW = ~20kWh

alaw005

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#3213130 2-Apr-2024 09:16

I turned the solar off completely last night and will see what happens. Calitec advise they can heat same amount of water circa 500 liters usage per day for only 4.4kwh, 75% less than current costs.

Spyware

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#3213132 2-Apr-2024 09:23

20 KWh is 330 litres 50 degrees.

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SATTV

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#3213134 2-Apr-2024 09:34

We used to have solar back in the late 70's early 80's, we would turn off our element at labour weekend and turn on around Easter, we very rarely ran out of hot water, it was only a 220l tank.

I think a plumber that knows solar will be able to resolve this fairly quickly.

Even at this time of year, depending on on what you have for panels you should still get a reasonable ammount of hot water.

John

I know enough to be dangerous

alaw005

37 posts

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#3213231 2-Apr-2024 14:10

I turned the solar off completely last night and will see what happens. Calitec advise they can heat same amount of water circa 500 liters usage per day for only 4.4kwh, 75% less than current costs.

WWHB

35 posts

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#3214777 5-Apr-2024 19:05

Look at the Sanden Ecoplus or Reclaim systems if your are looking at going down the Hot Water Heat pump route. They use CO2 as the refrigerant so much more environmentally friendly, the6 are also super quite and probably the best systems available in NZ. (Heat pump units are made by the same parent company in Japan).

I have the Sanden system myself and it took around $100 a month off our power bill

PolicyGuy

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#3214799 5-Apr-2024 20:56

WWHB:

Look at the Sanden Ecoplus or Reclaim systems if your are looking at going down the Hot Water Heat pump route. They use CO2 as the refrigerant so much more environmentally friendly, the6 are also super quite and probably the best systems available in NZ. (Heat pump units are made by the same parent company in Japan).

I have the Sanden system myself and it took around $100 a month off our power bill

I have had the Reclaim unit for about 18 months.
Very quiet, works like a charm, thoroughly recommended

alaw005

37 posts

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#3214801 5-Apr-2024 21:03

What is the cost of those systems, particularly the Sanden? I need a split system as can't put tank outside as doesn't fit in space but heat pump unit will. I'm also trying to understand the real difference between R32 and CO2.

Jase2985

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#3214805 5-Apr-2024 21:46

alaw005: What is the cost of those systems, particularly the Sanden?

https://www.hotwatercylinders.nz/product/rheem-ecoplus-heat-pump-hot-water-cylinder-system/

and the reclaim one is about the same price

Jase2985

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#3214829 5-Apr-2024 22:10

WWHB:

I have the Sanden system myself and it took around $100 a month off our power bill

how much hot water are you using?

WWHB

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#3214965 6-Apr-2024 09:51

Jase2985:

WWHB:

I have the Sanden system myself and it took around $100 a month off our power bill

how much hot water are you using?

I have 2 teenagers and had a 180litre mains pressure cylinder, we regularly ran out of hot water. My daughter could empty the cylinder herself, and that was with a 9 litre a minute flow restrictor on the shower head. (We tried to control excessive showers but can’t do anything if she is showering whilst I am out at work)
Since installing the Sanden system we have never run out of hot water.

The Sanden and Reclaim systems also have superb hot water recovery rates over standard electric cylinders.

tweake

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#3215055 6-Apr-2024 13:23

alaw005: What is the cost of those systems, particularly the Sanden? I need a split system as can't put tank outside as doesn't fit in space but heat pump unit will. I'm also trying to understand the real difference between R32 and CO2.

what gas is used changes its performance curve. ie how efficient it is at -10c than it is at 20c. especially important with hot water systems because of the high temp hot water gets to.

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