Reducing hot water costs

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Starlancer

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#315756 13-Aug-2024 17:18

Are there ways to reduce hot water costs?

Such as ripple control? Does that need me to acquire expertise or let a suitable electrician set that up for me?

And putting a restrictor into the shower rose to reduce shower pressure?

And can I add solar power supply to my mains cylinder?

I just found out Flick Electric offered me a 22.96c/kWh flat rate compared to Contact Energy’s 31.66c/kWh rate.

Also are there NZ based plumbing and hot water discussion forums on the Net?

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#3271167 13-Aug-2024 17:35

Starlancer:

Are there ways to reduce hot water costs?

Such as ripple control? Does that need me to acquire expertise or let a suitable electrician set that up for me?

Yes, you could use ripple control or you could install a simple Hot Water cylinder Timer, this will enable your HWC to only turn on in periods of cheap power. See more below

Starlancer:

And putting a restrictor into the shower rose to reduce shower pressure?

And can I add solar power supply to my mains cylinder?

You could put restrictors on your taps etc but you want to check if they need them first, work out how much water they are using to see if they need them. Should have a flow rate of 5-8L litres per minute.

You would be better to put solar on your whole house as you would get more benefit from it. Then you could use a HWC diverter to put that solar power into your HWC, this works really well but is costly.

Starlancer:

I just found out Flick Electric offered me a 22.96c/kWh flat rate compared to Contact Energy’s 31.66c/kWh rate.

Also are there NZ based plumbing and hot water discussion forums on the Net?

Depending on where you are and what kind of meter you have you could get a day/night rate which offers cheaper power at night and in conjunction with the timer mentioned before, heat your cylinder on the night rate. or go with someone with 3 hours of free power and heat it then.

Also shop round for power, those rates could be high for your region.

gzt

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#3271170 13-Aug-2024 17:53

I use a 6lpm water restrictor on a 9lpm shower head. Pressure is excellent I have that advantage. Hardly a noticable difference in practical showering.

gzt

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#3271171 13-Aug-2024 17:55

Are there ways to reduce hot water costs?

Rubber lagging is great if you have easy access to the pipes. It prevents waste in winter running the tap for ages dumping water and wasting heat until it arrives at the other end.

elpenguino

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#3271174 13-Aug-2024 18:30

Number one way with the quickest pay back period to reduce energy cost is to fit an insulation sleeve to the cylinder.

Even new cylinders benefit from that.

https://insulationwarehouse.co.nz/shop/product/greenstuf-eco-wrap-hot-water-cylinder-wrap/

https://www.cea.co.nz/product/hot-water-cylinder-wrap/

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tweake

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Uber Geek

#3271178 13-Aug-2024 19:01

Starlancer: Are there ways to reduce hot water costs?

Such as ripple control?

ripple control depends on if the local lines system has it. if they do then the house typically already has it from new. if you do already have it, its just a matter of signing up to the correct plan.

you can fit solar panels direct to hot water cylinder, there is special systems for existing cylinders.

if your cylinder is old then it may be worth while to upgrade to a heat pump model.

upgrade insulation. however if you have a hot water cupboard that doubles for storage you might be better to upgrade the closets insulation.

but also be realistic. how much hot water do you actually use and is it going to be a meaning full saving.

OldGeek

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#3271195 13-Aug-2024 21:14

I have installed a timer with a Bluetooth interface that switches off the electricity supply to my hot water cylinder at my switchboard. I have programmed it via a phone app to switch off at peak electricity pricing times so that all hot water heating is at off-peak times.

memo BT1 - Vemer S.p.A.

Note that this is a 2-circuit timer - each separately programmable. Once you pair the device to a phone, existing settings can be downloaded to the app. Note that the English translation is a bit suspect but it is usable. Note that the settings are stored in non-volatile memory and battery-backup is used on time settings. This means that in the event of a power cut, settings are retained as is the time-of-day clock.

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prob

225 posts

Master Geek

#3271276 14-Aug-2024 07:38

I have a Iconic Wiser / PDL / Snieder Bluetooth timer. This is standard PDL kit that any electrician can install. I get power from Z Energy and they have free power from 3 to 6 am and that's when I heat our water.

Easy to make changes from my phone using an app.

Note this timer can also use Zigbee.

https://www.kiwisparks.co.nz/products/bluetooth-hot-water-cylinder-control-kit?variant=42444211749112

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raytaylor

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#3271641 14-Aug-2024 21:27

1) Ripple Control - Time Shifting of water heating

Call your electricity retailer and ask if they can give you advice on how to switch your electricity connection to a "Controlled" plan if you are currently "uncontrolled".

This will require a ripple or pilot controller to be installed by an approved electrician who will then send a certification to the retailer and lines company.

You will get a discount on your electricity bill because of this.

However most households already have this installed - it was required by law at one point. Most people dont even know they have it already.

The local lines company can switch off your hot water reheating for several hours at a time during the peak periods of the day.

It is unlikely that you will use all your stored hot water during these few hours and if you somehow do (45 mins of showering for a typical 180L tank) you just wait for a couple of hours and the water will begin to reheat again once the peak has passed and the lines company has spare capacity again.

When a power retailer provides a price quote, they will look up in a national database to see if your household is controlled or not.
Uncontrolled households pay more for lines maintenance and upgrades because they typically contribute to the evening peak more than controlled households.

2) Solar power

Its not worth installing solar water heaters anymore - solar electric panels have come down in price so much now and they are much more versatile with what you can do with them.

You can install a solar power system and then add a timer or a diversion controller so the hot water is heated by electric solar panels rather than grid supply.

3) Timer for off-peak rates

You can install a timer on your hot water cylinder so your water heating is done at times of cheap electricity, not just when it suits your local lines company.

Eg. My local lines company switches on the water reheating at about 7-8pm but my free power doesnt start until 9pm on the contact good nights plan.

So i have a wifi timer which waits until 9pm to start the water reheating in the free power period.

Because its only 3 of us and occasionally a girlfriend visiting in my flat, our 180L tank easily lasts us a day until the next 9pm rollover for reheating.
Effectively all our hotwater is free in my house.

If we did run out of hot water and didnt want to wait until 9pm for more free hot water, we can push a button on the timer and it will instantly turn on and start heating - 20 minutes later there is enough hot water for a shower.

Originally I had the timer set for a 30 minute boost at 6am because one of us showers before work in the morning but I found it wasnt needed.

Ray Taylor

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raytaylor

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#3271643 14-Aug-2024 21:32

prob:

I get power from Z Energy and they have free power from 3 to 6 am and that's when I heat our water.

Side question: What made you choose that plan vs contacts good nights plan which is the free 9pm-midnight?

I was looking at changing to it (I dont have an EV) but decided 9pm was more convenient for water heating and household heating.

The Z energy plan would mean our night store heaters could recharge and the house would be super warm when we wake up in the mornings. At the moment they charge up from 9-midnight and so they are still putting out a little bit of heat at 6am (they are really designed for an 8 hour charge up) and the house is reasonably warm to the point we dont have to turn on the heat pump.

But i ended up deciding the 9pm-midnight was still the more convenient time for us as it meant the dryer and dishwasher could run at that time too when noise isnt so annoying.

Ray Taylor

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coffeebaron

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#3271674 15-Aug-2024 07:04

Got teenagers? Maybe try a coin operated shower. Increase revenue to offset power bill and reduce it at the same time. Win win :)

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#3271803 15-Aug-2024 09:23

coffeebaron: Got teenagers? Maybe try a coin operated shower. Increase revenue to offset power bill and reduce it at the same time. Win win :)

Was reading the comments waiting for this.

Cheapest option to implement immediately is to use less hot water in the first place.
Not always an option but worth considering also.

russelo

328 posts

Ultimate Geek

#3271810 15-Aug-2024 09:30

raytaylor:

So i have a wifi timer which waits until 9pm to start the water reheating in the free power period.

What wifi timer device did you use? Do you have link for it?

hamish225

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#3271880 15-Aug-2024 09:52

If you use a lot of hot water and are looking at replacing your hot water cylinder, you could consider a heat pump hot water setup. they use 1/3 - 1/4 the power vs a normal resistive element, but the up front cost is a bit more.

*Insert big spe*dtest result here*

raytaylor

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#3272168 15-Aug-2024 16:43

russelo:

raytaylor:

So i have a wifi timer which waits until 9pm to start the water reheating in the free power period.

What wifi timer device did you use? Do you have link for it?

I cant remember the brand but its a smart wifi 16 amp din rail mounted one from trademe.

I used to have a standard timer but it crapped out - the heat inside the cupboard from the hot water cylinder nearby killed it very quickly so this one is a Wifi timer which connects to the wifi each time the ripple controlled supply powers it up, and then it syncs its clock via ntp and controlled via the Tuya app.

Ray Taylor

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larknz

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#3272220 15-Aug-2024 19:32

If you are losing that amount of heat from your cylinder then a cylinder wrap should make a significant difference. Ideally the the temperature in a HWC should be the same as the rest of the house.

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