Deciding on a continuous flow hot water system

Forums › Home Workshop DIY › Deciding on a continuous flow hot water system

craft1

77 posts

Master Geek

#108248 27-Aug-2012 21:20

I saw a thread similar to this on geekzone but it is locked now so thought I should open a new one.

My wife and I are looking at doing up the bathroom and while we do that, switching to a gas instant hot water system.

I am used to hearing everyone talk about Rinnai and one of the plumbers quoted a Rinnai 26 but the second guy quoted for a Bosch 26E.?

I havent heard much about these before but he reckons its cheaper and better.? Doing a search online seems to confirm that it is pretty good but was wondering if anyone here has had experience with the Bosch one before I make my decision.

Thanks in advance.

Edit: In case anyone asks.? For now it is just my wife and I plus 2 very young children, aged 3 and under.? I forsee a lot of hot water usage in the future but its fairly minimal for now although the small hot water cylinder we are replacing does struggle every now and again.? That is another reason why we are keen to upgrade.

JimmyH

2886 posts

Uber Geek

#677836 27-Aug-2012 21:37

I put a Bosch unit in about 10 years ago, and don't regret it.

Not really any negatives, other than costing about $150(ish) more than a cylinder because of the install costs.

On the plus side it cut my gas bill quite a bit (don't have to keep 160litres of water at 60+ degrees 24/7 for only occasional use), freed up the hot water cupboard which I could convert to storage, I never run out of hot water, and if I have kids visit I can easily set the temperature to something well below scalding on the control unit.

craft1

77 posts

Master Geek

#677843 27-Aug-2012 21:48

I'm definitely looking forward to not running out of hot water, and the freeing up of half of my storage cupboard is a huge bonus too.

freitasm

BDFL - Memuneh
79319 posts

Uber Geek

Administrator

ID Verified

Trusted

Geekzone

Lifetime subscriber

#677845 27-Aug-2012 21:50

Moved topic to correct forum.

scuwp

3888 posts

Uber Geek

#677861 27-Aug-2012 22:13

Have had Rinnai in the past houses and now Bosch. I would have to say the Bosch does seem quieter and potentially a bit faster.

They do make a bit of noise on start up so don't put outside the kids bedroom. Location is also key to minimise distances from taps and therefore the time to get hot water through.

We don't have the electronic controllers this time, but I think if it's in the budget they are worth it. Great protection for young ones as well.

You won't regret the change, especially with a growing family.

Lazy is such an ugly word, I prefer to call it selective participation

CYaBro

4590 posts

Uber Geek

ID Verified

Trusted

#677889 27-Aug-2012 23:04

I'll let you know in a few weeks as we've gone for a Rinnai HD250 for our new house.
Was told by the plumber to get Rinnai over Bosch as Bosch have had problems.

From my research I decided it wasn't worth the extra money to go for the latest EF models that have the secondary heat exchanger, to preheat the water using the exhaust gas, but these are required by law in the UK from what I could tell.

Also liking the idea of setting the temp with the controllers for kids baths or showers.

Opinions are my own and not the views of my employer.

Hiamie

354 posts

Ultimate Geek

#677908 28-Aug-2012 03:49

Mine (can't remember the brand) is quite noisy each time it starts and stops.

Bear that in mind when you decide on its placement. I wish I hadn't had it installed on the outside wall near to my daughters bedroom.

farcus

1558 posts

Uber Geek

#677909 28-Aug-2012 04:24

I've often wondered about the economy of gas water heating.

With electric cylinders we usually heat the water up to about 55 to 60 degrees and then cool it using cold water to about 40 degrees for our showers, baths, dishes etc. this seems like lots of wasted energy.
With gas you can specify the temp you want right off . . . . but the cost of gas seems expensive and pretty changeable??
How do people with gas systems find the economy compared to the elec cylinder?

Quic Broadband

Move to New Zealand's best fibre broadband service (affiliate link). Free setup code: R587125ERQ6VE. Note that to use Quic Broadband you must be comfortable with configuring your own router.

davidcole

6041 posts

Uber Geek

Trusted

#677923 28-Aug-2012 07:39

farcus: I've often wondered about the economy of gas water heating.

With electric cylinders we usually heat the water up to about 55 to 60 degrees and then cool it using cold water to about 40 degrees for our showers, baths, dishes etc. this seems like lots of wasted energy.
With gas you can specify the temp you want right off . . . . but the cost of gas seems expensive and pretty changeable??
How do people with gas systems find the economy compared to the elec cylinder?

I'm not sure I ever noticed a difference in pricing, basically what I was paying in water heating shifted to the gas bill, so over all I think I paid the same (hard to tell when prices of electricity and gas are both increasing etc).

But it's more than made up in never running out, and explicitly setting the temp for a bath/shower. I do find that when doing the dishes say (that the hot water needs to run a bit more, else if you shut if off then start it again, you get a cold spot in the water..

Previously known as psycik

Home Assistant: Gigabyte AMD A8 Brix, Home Assistant with Aeotech ZWave Controller, Raspberry PI, Wemos D1 Mini, Zwave, Shelly Humidity and Temperature sensors
Media:Chromecast v2, ATV4 4k, ATV4, HDHomeRun Dual
Server Host Plex Server 3x3TB, 4x4TB using MergerFS, Samsung 850 evo 512 GB SSD, Proxmox Server with 1xW10, 2xUbuntu 22.04 LTS, Backblaze Backups, usenetprime.com fastmail.com Sharesies Trakt.TV Sharesight

scuwp

3888 posts

Uber Geek

#677928 28-Aug-2012 07:59

farcus: I've often wondered about the economy of gas water heating.

How do people with gas systems find the economy compared to the elec cylinder?

It's a true 'user pays' system. Yes it probably does use a bit more energy when running, but you are not paying to store hot water you are not using it, so IME it is definitely cheaper. I know 3 people that have recently converted from the old hot water cylinder to gas/instant...and they all rave about it, especially the increase in water pressure.

Lazy is such an ugly word, I prefer to call it selective participation

myopinion

938 posts

Ultimate Geek

#677939 28-Aug-2012 08:27

Here's a link from the Energywise site that shows the indicative costs of running each type of heater. Looks like water storage and continuous flow are about the same cost to run:

http://www.energywise.govt.nz/sites/all/files/hot-water-running-costs-graph-05-10.JPG

We just replaced our hot water cylinder and had the option of gas but we are on tank water so opted for storage again.

craft1

77 posts

Master Geek

#678152 28-Aug-2012 13:25

Thanks for all your responses. I've decided to go for the Bosch unit.
I understand there are pros and cons for each option but im really looking forward to getting space back and never running out of hot water.

mattwnz

20181 posts

Uber Geek

#678161 28-Aug-2012 13:32

The other brand that does them is Rheem. But I think all the units are pretty similar, and I don't think any one unit is more reliable than another. I have a rinnai, and got it becuase I liked the control panel and it's features over other brands at the time. The best person to ask though would be someone who services them. They are very expensive to fix though when they go wrong, and can be cheaper just to switch with a new one. I was told you are lucky to get 10 years out of them.

sleemanj

1490 posts

Uber Geek

#680258 2-Sep-2012 00:04

We had a Bosch for at least 10 years (actually thinking about it, more like 15 I think), it was a battery ignited one (double-d) so no frost protection or anything, so probably not bad given that it was outside in Christchurch for say 15 winters.

Just in the last couple of weeks it finally gave up the ghost (been coaxing it along for a year with bodged up repairs etc) due to basically rusting out the burners and falling apart in general.

Have now replaced it with a Bosch 21e.

In my research, I found that the specs and offerings and prices from all the companies are about the same, Bosch won out simply because that was most readily available from a plumber here.

The only downside with the new ones, is that you just can't get natively battery ignited ones any more, they all require mains power (with the exception of 1 Bosch one which isn't suitable for colder climates like much of NZ) to ignite, run a blower, protect against frost etc. (edit to add: there are some no-name ones on Trademe which are still battery ignited, but I concluded that it would probably not last long as an outdoor installation, and not readily available from plumbers etc if anything went wrong)

I'll be getting an inverter as a backup (or possibly, as a primary, connected with a battery and solar panels I have around), unfortunately from reading spec sheets, I think that a pure sine wave one will be required, but at most when running I think they use about 60 watts (haven't plugged my meter into it personally to check though).

FWIW, here are my notes from when I researched the replacement...

3 main brands available

Bosch

Rinnai

Rheem

All have products which are roughly the same in terms of capability and cost.

Bosch

Have a no-power version “Hydropower” but stated as not suitable for cold climates like Chch, so can not use here.

Power required version is “Electronic Highflow”, recommended for 1 bathroom in Christchurch is 21L/Min version “Electronic Highflow Bosch 21e”

Local company Revolution Plumbing and Gas advertised on Trademe,

21L... $1250

26L... $1400

Also on trademe “Jeff Evans Plumber Ltd” in Hokitika sells 21L version for $1165, and 26L for $1315 with free shipping – but should consider warranty issues if it went wrong, probably better to try and deal with 1 company.

Mitre10Mega have 25L $1498

Rheem

All require power.

Similar specifications, 20L/min is closest to Bosch, also in 24, 27 versions.

Model “874020NFZ/LFZ” 20L/min

No local prices on trademe, prices in north island for comparison

20L... $1050,

24L... $1120,

27L... $1300

Dealers: Bunnings, Mitre10, Placemakers, Carters, Edward Gibbon (Plumbing Plus), ITM.....

Note: Mitre10Mega also sell “Paloma” which seems to be another brand of Rheem (or Rheem is a subsidiary of Paloma), probably widely similar in specifications.

Rinnai

All require power.

Similar specifications, 20L/min is closest, also 24, 26.

Model “Infinity VT20”/VT24/VT26

No local prices on trademe, prices in north island for comparison

20L... $1170

24L... $1260

26L... $1370

Dealers: Edward Gibbon (Plumbing Plus)

Conclusion

Any of the offerings from Bosch, Rheem or Rinnai seem adequate, and roughly the same in capabilities and likely pricing from plumbers directly around $1300 (more from retail stores).

Paloma also seems often offered by plumbers and I think this is related to Rheem and will have similar specs.

---
James Sleeman
I sell lots of stuff for electronic enthusiasts...

craft1

77 posts

Master Geek

#680464 2-Sep-2012 17:49

Thanks for the detailed info.
My biggest concern was that one brand may be significantly better or worse than the others, ie: Bosch is not as good as a Rinnai, etc...
But from what I've read here (and via google), they are all pretty much on a par so I'm happy going with the Plumbers recommendation on this one.