Hot Water Cylinder - Advice needed please

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graham007

221 posts

Master Geek

#272103 9-Jun-2020 17:31

Seems like my house needs a new one , the existing one from long time back has minor leaks

Hot water cylinder 3kw electric. Can I please get brand recommendation

And also approx ballpark figure I expect to pay incl install in Auckland

And if you have any exceptional plumber to recommend.

Thanks a lot

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#2501677 9-Jun-2020 19:23

depends on a few things

Size, dimensions, low of high pressure, do the valves etc need replaced?

Rheem and HJ Cooper are good in my experience

OldGeek

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#2501725 9-Jun-2020 20:15

It depends on a lot of things - like do you have Natural Gas or bottled LPG (45KG switched) cylinders available? I would suggest talking to a tradie who is a Plumber AND Gasfitter. If practicable consider an on-demand gas-fired hot water heater such as a Rinnai A26. Your cylinder stores heated water and the electricity used to heat it can be turned off at peak times to reduce electricity demand. These devices can use either Natural Gas or LPG. Pros and cons are dependent on circumstances where you live and how you use hotwater. Both Natural Gas and LPG are fossil fuels whereas electricity in NZ is largely from renewable sources.

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sqishy

470 posts

Ultimate Geek

#2501772 9-Jun-2020 22:13

I've got the Rinnai Continuous Hot Water Solution - best thing ever

-natural gas

-has never broke

-really good pressure

-never run out of hot water

-seems healthier than stored hot water in a tank

-no tank to worry about - use space for something else

-small unit on outside of house

nickb800

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#2501786 10-Jun-2020 05:34

These guys have install packages on their website https://www.hotwatercylinders.nz

Depending on size, just under $2k seems standard for a straightforward replacement

timmmay

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#2501792 10-Jun-2020 05:55

If it's old it's probably low pressure. You could take the opportunity to upgrade to mains pressure and have much nicer showers. I did that when I did a bathroom renovation about ten years ago, great move.

graham007

221 posts

Master Geek

#2501794 10-Jun-2020 06:24

Thanks so much for all the replies so far , really helpful indeed

graham007

221 posts

Master Geek

#2501795 10-Jun-2020 06:24

Thanks so much for all the replies so far , really helpful indeed

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fe31nz

1228 posts

Uber Geek

#2502603 10-Jun-2020 23:42

There is another option to consider these days. You can get heat pump hot water cylinders. They are not at all cheap, but if you are a big user, the 4:1 ratio of heat provided to electricity used may well make the lifetime cost worth it.

mattwnz

20141 posts

Uber Geek

#2502607 11-Jun-2020 00:41

I would get one with a stainless tank at least, as they have a longer warranty and should be more durable. But you should check with a professional for advice on this. . Next door neighbours 5 year old one just failed in a new house and leaked, and it only had a 5 year warranty. Is going to cost thousands to replace including labour.

nickb800

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#2502662 11-Jun-2020 06:01

fe31nz:
There is another option to consider these days. You can get heat pump hot water cylinders. They are not at all cheap, but if you are a big user, the 4:1 ratio of heat provided to electricity used may well make the lifetime cost worth it.

Hot water heat pumps may well be worth it for the OP, but worth mentioning that 4:1 (COP of 4) is not a realistic ratio to expect.

BRANZ research on real life examples in NZ houses found an actual COP of around 1-2. Heat pumps aren't as efficient in heating hot water as they are for heating air

kotuku4

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#2502749 11-Jun-2020 09:15

I had an 20 year old low pressure cylinder replaced. Plumber replaced all valves, fittings and some pipe. A drip tray with overflow pipe outlet, and improved seismic restraint per current building code. The cost was north of $4000 a few years ago.

I did stay with basic low pressure bottom feed, plumber confirmed that they last much longer, slightly larger cylinder for more storage. I have a solar PV controller that heat the hot water element primarily from solar power.

There are options for solar/heat pump ready, dual element. Be aware that cylinders with anodes need these checked/ replaced and you need access to be able to do that.

I also stripped the shelves from the cupboard for access, and rebuilt and painted them. Added insulation to pipes.

Would have to change some plumbing fittings, such as shower, basin, and kitchen sink mixers if changing from low to mains pressure, consider the cost.

timmmay

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#2502754 11-Jun-2020 09:24

When we changed to high pressure our existing old pipes and fittings were fine. We did replace the whole bathroom down to the studs at the same time, so it was just kitchen and laundry. We also moved the hot water cylinder to the huge ceiling cavity including drip tray and building a solid wooden frame around it with good restraints. If it fails sooner than low pressure we'll be fine replacing it and enjoying much nicer showers. Fittings aren't that expensive to replace, I replaced my own kitchen mixer - took ages as I didn't know what I was doing but not expensive.

BiffTannen

11 posts

Geek

#2503167 11-Jun-2020 18:28

If you're on low pressure for hot water and switch to mains, I'd be wary of what it can do to pipes. I've heard of cases where in older pipes, they're not used to the higher pressure and end up leaking or bursting. If you're replacing the cylinder, it might also be a good time to check that none of your pipes are the black 'Duxquest' types used most commonly in the 1980s-they are prone to failure bigly and are simply defective.

AklBen

102 posts

Master Geek

#2516573 3-Jul-2020 09:11

The previous owners of our house decided it was a great idea to install the hot water cylinders underneath the house and un-insulated. Under the house is not a basement, it's under the house on dirt...

I'd like to move to instant HW with LPG.

Question is, as there's a small HWC underneath the kitchen just for the kitchen, and the rest of the house is supplied by the larger HWC underneath the house at the back would there be much gain in removing that small one underneath the kitchen?

The benefit of leaving it would be keeping the incredibly hot and instant water in the kitchen. If the gas unit was placed at the rear of the house it's closer to the bathrooms meaning faster access to the hot water, but slow to the kitchen and vice versa.

I guess we could insulate that under-house small HWC - consumption from small HWC must be fairly low right?

Tracer

343 posts

Ultimate Geek

#2517079 3-Jul-2020 23:24

AklBen:

The benefit of leaving it would be keeping the incredibly hot and instant water in the kitchen. If the gas unit was placed at the rear of the house it's closer to the bathrooms meaning faster access to the hot water, but slow to the kitchen and vice versa.

And with gas, if you turn the tap off and then realise you want it on again, you get a little bit of hot water, then wait that whole time again for the califont to detect flow, ignite, and the water to get all the way through again.

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