Moving the location of hotwater cylinder (internal to external) -cost and gotchas

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blackjack17

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#311565 27-Jan-2024 10:24

Anyone have any experience with moving a hotwater cylinder from an internal to external location (as in getting a plumber to remove the old one and getting a properly externally rated hotwater cylinder in an outside location).

We would love to free up some space in the laundry and we currently have a small low pressure system. We have been quoted just over $4000 to remove the old one and install a new 180L Rheems external mains cylinder. This includes all electrical and up to 10m of piping. We did have a second quote for $500 more, but the guy didn't even ask for photos it was completely site unseen. The $4000 quote, he didn't come out but a number of photos and back and forwards questions. The price also includes an inspection of existing fittings to ensure mains compliant.

We are in Auckland and the outdoor location is protected from the elements. Should we be looking at getting a timer installed at the same time?

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#3187214 27-Jan-2024 10:45

I think you mean replacing an inside hot water cylinder with a new outside hot water cylinder, rather than moving a hot water cylinder.

We did something similar about ten years ago. We had the hot water cylinder in the bathroom removed, and had a new hot water cylinder put in the ceiling, with a LOT of bracing around it and a drip tray. There was quite a bit of pipe changes, but we had the bathroom completely renovated. It worked well. We had a digital timer installed on the switchboard, which saved money when we were using power plans had different prices at different times. These days we'd probably go for a WiFi type controller, but we don't use time based power plans, so not sure if we'd bother.

blackjack17

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#3187215 27-Jan-2024 10:48

timmmay:

I think you mean replacing an inside hot water cylinder with a new outside hot water cylinder, rather than moving a hot water cylinder.

We did something similar about ten years ago. We had the hot water cylinder in the bathroom removed, and had a new hot water cylinder put in the ceiling, with a LOT of bracing around it and a drip tray. There was quite a bit of pipe changes, but we had the bathroom completely renovated. It worked well. We had a digital timer installed on the switchboard, which saved money when we were using power plans had different prices at different times. These days we'd probably go for a WiFi type controller, but we don't use time based power plans, so not sure if we'd bother.

Yes have edited title. Moving the location of a hotwater cylinder and replacing it.

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SATTV

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#3187217 27-Jan-2024 10:54

How many people in your household, if there is only one or two of you then 180l is fine, you could take the opportunity to go larger, we went to 220l and never ran out of hot water, even in winter.

I like long and hot showers :-)

John

I know enough to be dangerous

blackjack17

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#3187218 27-Jan-2024 11:02

SATTV:

How many people in your household, if there is only one or two of you then 180l is fine, you could take the opportunity to go larger, we went to 220l and never ran out of hot water, even in winter.

I like long and hot showers :-)

John

2 adults and 2 children. Currently have a 135L low pressure and have only once run out when I wasn't paying attention to my daughter and she had a 40min shower. But generally we all have pretty short showers and quite eco friendly.

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tweake

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#3187221 27-Jan-2024 11:09

blackjack17:

Anyone have any experience with moving a hotwater cylinder from an internal to external location (as in getting a plumber to remove the old one and getting a properly externally rated hotwater cylinder in an outside location).

We would love to free up some space in the laundry and we currently have a small low pressure system. We have been quoted just over $4000 to remove the old one and install a new 180L Rheems external mains cylinder.

i looked at it recently due to mine leaking.

the thing i don't like about external hot water tanks is lack of insulation on the tanks. keep in mind that internal tanks are insulated and you have the house insulating them as well. plus you want to make sure every part of the piping is well insulated as thats a big factor.

price wise $4k is no bad at all. my internal was around that, but it was a more expensive than normal tank and required a bit of plumbing change to go from low pressure to mains.

if your going to go external tank, consider heat pump hot water. at least then the cheaper heating will offset increased losses.

Goosey

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#3187223 27-Jan-2024 11:15

If you are going from low pressure to mains pressure then I’d be double checking all the taps and plumbing fittings in your house can handle it.

e.g. If low pressure was installed then taps and shower heads may have also been spec’d for low pressure.

tweake

2391 posts

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#3187226 27-Jan-2024 11:21

Goosey:

If you are going from low pressure to mains pressure then I’d be double checking all the taps and plumbing fittings in your house can handle it.

e.g. If low pressure was installed then taps and shower heads may have also been spec’d for low pressure.

thats a good point.

going from low pressure to mains, i had to adjust my shower but thats a crappy all pressures setup not a good unequal pressures setup which will be worse.

plus some hot taps do not like the high pressure. good quality methhaven taps but very old, they expand with the pressure and heat, so water slows when it heats up and leaks when it cools. will have to replace it at some point. the cheap nasty new bathroom taps not a problem.

RunningMan

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#3187229 27-Jan-2024 11:28

Going from low to mains pressure generally results in higher usage, so you may need to go larger in tank size to avoid running out of hot water.

michelangelonz

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#3187230 27-Jan-2024 11:31

If I remember rightly a building consent might be required if moving the HWC and/or changing from low to high pressure.

rscole86

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#3187232 27-Jan-2024 11:33

We went through this in June 2023, in Wellington.

Total cost $4700 Inc GST, including electrical work ($780 Inc GST) and removal of old tank.

We went from 180L LP to 180L mains.
Rheem stainless steel (32518015), around $1400 Inc GST.
Labour was one guy for 8 hours, one for six and his son for six (free).

We could have gotten it cheaper, but our old cylinder element died so needed a quick replacement. The price likely reflects the work being done within 48 hours of the old cylinder dying and the new install completed.

The install went into an existing, covered, concrete pad which backed into the underfloor plumbing for the kitchen, so other than drilling through the cinder block wall, it was easy install.

I did a real quick, back of the envelope, cost comparison of heat pump hot water, including multi split units, and even with our friends and family discount, it was going to be well over ten years to break even. (Plus a number of other factors that wouldn't have made it a good idea)

bigmacpaddy

71 posts

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#3187233 27-Jan-2024 11:35

Have done the same thing to free up space in kitchen. Rheem 180L outdoor unit.

Have built small walls and roof around it to help keep debris away.

Plumber had to adjust something in the shower but no other issues with our specific taps.

We also put a little plastic regulator in between the shower head and hose to lower pressure/wasted water as we were using more water on a mains pressure system.

rscole86

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#3187234 27-Jan-2024 11:41

I replaced my own shower heads and put flow reducers in some taps, excluding bath and laundry.

tweake

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#3187237 27-Jan-2024 11:58

rscole86: I replaced my own shower heads and put flow reducers in some taps, excluding bath and laundry.

speaking of laundry, i had to readjust the hot water on the washing machine. quite common to remove the restrictors and even the filters on the hot side to improve the flow with low pressures. which all needs undoing when going to mains.

blackjack17

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#3187254 27-Jan-2024 13:03

michelangelonz:

If I remember rightly a building consent might be required if moving the HWC and/or changing from low to high pressure.

I don't think so provided it is only connected to a controlled heat source (i.e. electricity and not a wetback) and it is carried out by a licensed plumber .

https://www.canibuildit.govt.nz/replacement-or-repositioning-of-water-heater-connected-to-controlled-heat-source/

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kingdragonfly

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#3187742 28-Jan-2024 16:50

Some people have mentioned heat pump hot water already, "HPHW"

HPHW will suck heat from wherever it is, and cause a tiny bit of condensation, so one that's outside can be an advantage; it won't make for a cold basement.

NZ Herald: Element's Guide: Heat Pump Water Heaters
...
An average HPWH is three to four times more efficient than conventional electric water heaters.

Consider that 30% of the average power is dedicated to heating water, and do the maths.
...
In a new build environment, the payback period can be one to three years for a family of four or more. An annual energy saving of $600 to $700 is readily achieved, and can increase by $200 to $300 per additional resident.

In a retrofit environment, where an existing tank needs to be replaced, or the hot water system is being upgraded to mains pressure, the marginal cost is about $800 to $1000, which can provide a payback of 18 months to two years.
...

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