Instant Hot Water systems

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DamageInc

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#302930 4-Jan-2023 17:33

Happy new year everyone.

I have some plumbing issues that need fixing and they're large enough to warrant including a possible change from an electric hot water cylinder to an instant hot water system using gas/gas bottles.

In the past I've heard of people opting for instant whenever the cylinder shat itself. Although our cylinder is in good working order, is this still the recommended course of action?

Does anyone have any recommendations on which system to go for?

FYI on the plumbing issues - we've had numerous leaks with the current pipework in the ceiling and walls and we're at that point of getting all the pipework renewed for our own piece of mind.

Any thoughts much appreciated.

Pop! OS

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#3016944 4-Jan-2023 18:21

Changing from electric to gas hot water will significantly increase your household's carbon footprint: this may or may not be a personal consideration for you.

If you're getting gas hot water, which means you'll use quite a lot of gas every day, the daily 'pipe' charge may be worth paying as the per-kWh charge will be lower than for bottles, so piped gas may be more economical. You'll need to talk to your gas supply companies about pricing.
When I had gas hot water, it cost me about $80/month, but $50 of that was 'pipe' charges, the gas was about 7c/kWh [Genesis Energy, prices including GST]. You will need to do your own calculation based on how many people are in your house, mine is just me.

Two other considerations:

Instant heat gas hot water services are grotesquely energy inefficient, almost all the heat goes out the vent, relatively little goes into the water. There are mains pressure gas hot water systems with a tank, some are for internal mounting and need a flue, others are for outside mounting.
Instant hot water systems never run out until the gas runs out. This is a feature but also a bug ... especially if you have teenage daughters who given the chance may take l-o-n-g showers. LOL

Edit: spelling, formatting

k1w1k1d

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#3016945 4-Jan-2023 18:28

I thought the government was trying to discourage new gas installations?

pih

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#3016949 4-Jan-2023 18:40

Some good thoughts here. Having had several hot water cylinders and several continuous hot water systems, I'm on the fence about them.

With the current continuous system I LOVE the ability to control errm, I mean gently discourage my teenager's tendency for ridiculously long showers. But at the same time I like the ability to dribble hot water slowly out of a cylinder (eg. for shaving), which you can't really do with a continuous system, as it has a minimum flow rate before switching on.

I like the power savings of a gas system at rest, but I also like having a perpetually heated and dry hot water cupboard.

I like the fact the continuous hot water "never runs out", but you begin to rely on that a bit too much if you have bottled gas ... and the gas runs out.

You'll have to weigh these things up for yourself, but hopefully this gives you a bit more to consider!

WyleECoyoteNZ

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#3016951 4-Jan-2023 18:45

First up, I rent, so using what is provided.

We are on Gas Bottles here (2 x45Kgs). Family of 4 (2 adults & 2 kids). Gas used for hot water heating and hobs in kitchen.

Just recently connected (again) and looked around at suppliers.

Genesis were either, depending on plan, $135.70 per bottle (energy basic) or $150.48 per bottle (energy plus), plus $5.75 per bottle a month.

RockGas are $134 per bottle and then $115.00(?) per year (for both bottles for cylinder rental)

I ended up going with RockGas, as 1) Had a credit with them from being with them 7 months ago, and 2) Genesis annoyed me with different pricing depending on the plan.

We, can't speak for others, turn off the new cylinder when delivered, otherwise the system tends to use both cylinders equally. Roughly, in summer around 5 - 5 1/2 weeks per cylinder, maybe a little less in winter.

For my area, delivery days are Monday & Wednesday, so you do need to keep an eye on cylinder levels, and plan\order accordingly.

billgates

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#3016999 4-Jan-2023 18:55

If the hot water cylinder has not given you any troubles, then you are better off just keep using it and get your plumbing sorted? If you are looking to save $ on power bills, then you could replace it with a heat pump hot water cylinder. We have gas infinity on mains gas that we installed 2 years with our house build but I regret it now as we just got solar pv setup and the hot water cylinder would make complete sense now. I will just have to wait for either the gas infinity system to die or gas to become expensive which it is not atm as I get a good discount from Genesis. We pay $1incl GST for daily charge and 6.5c incl gst for usage.

Do whatever you want to do man.

lxsw20

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#3017014 4-Jan-2023 19:22

My folks have gas hot water, to get around the running out, they just turn off one bottle, wait for one to go empty and then order a replacement. It also stops the system flicking between bottles in cold weather when they are low.

Other option is to have a BBQ 9KG bottle around and you can use that in an emergancy.

Personally I'd be looking at other options, bottled gas isn't getting any cheaper.

mentalinc

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#3017168 5-Jan-2023 07:06

Not sure why you'd turn off one of the bottles?
They're designed to be both available so if you have all the hobs on, and someone having a shower/using hot water there is enough gas pressure available to meet the needs.
They should connect with a device that shows when the bottle is empty to reorder.

But as above, 100% don't install gas new now. Heat pump hot water and induction cooktop are the two better replacements.

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davidcole

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#3017169 5-Jan-2023 07:22

mentalinc:

But as above, 100% don't install gas new now. Heat pump hot water and induction cooktop are the two better replacements.

heat pump,hot water isn’t continuous though correct? So uses a tank again? So don’t you lose the space benefits of continuous?

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PolicyGuy

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#3017172 5-Jan-2023 08:00

davidcole:

mentalinc:

But as above, 100% don't install gas new now. Heat pump hot water and induction cooktop are the two better replacements.

heat pump,hot water isn’t continuous though correct? So uses a tank again? So don’t you lose the space benefits of continuous?

My heat pump hot water system is entirely outdoors, I think this is the usual way of installing them.
Some of the leading brands integrate the heat pump and the tank in a single unit, which obviously has to go outdoors. Other brands have a separate heat pump and storage tank, so you could put the tank indoors and the heat pump outdoors, but I don't think that is common.

Jase2985

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#3017174 5-Jan-2023 08:04

davidcole:

mentalinc:

But as above, 100% don't install gas new now. Heat pump hot water and induction cooktop are the two better replacements.

heat pump,hot water isn’t continuous though correct? So uses a tank again? So don’t you lose the space benefits of continuous?

the OP already has a tank

DamageInc

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#3017187 5-Jan-2023 09:16

billgates:

If the hot water cylinder has not given you any troubles, then you are better off just keep using it and get your plumbing sorted?

After reading all the replies, I'm leaning towards keeping the water cylinder. There's nothing wrong with it.

Pop! OS

DamageInc

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#3017188 5-Jan-2023 09:17

pih: Some good thoughts here. Having had several hot water cylinders and several continuous hot water systems, I'm on the fence about them.

With the current continuous system I LOVE the ability to control errm, I mean gently discourage my teenager's tendency for ridiculously long showers. But at the same time I like the ability to dribble hot water slowly out of a cylinder (eg. for shaving), which you can't really do with a continuous system, as it has a minimum flow rate before switching on.

I like the power savings of a gas system at rest, but I also like having a perpetually heated and dry hot water cupboard.

I like the fact the continuous hot water "never runs out", but you begin to rely on that a bit too much if you have bottled gas ... and the gas runs out.

You'll have to weigh these things up for yourself, but hopefully this gives you a bit more to consider!

Some good points, thanks.

Pop! OS

DamageInc

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#3017190 5-Jan-2023 09:20

mentalinc:

Not sure why you'd turn off one of the bottles?
They're designed to be both available so if you have all the hobs on, and someone having a shower/using hot water there is enough gas pressure available to meet the needs.
They should connect with a device that shows when the bottle is empty to reorder.

But as above, 100% don't install gas new now. Heat pump hot water and induction cooktop are the two better replacements.

When we bought the house 6-7 years ago, the gas mains was disconnected. Meter is still here.

Pop! OS

DamageInc

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#3017195 5-Jan-2023 09:28

Morning all.

Thank you so much for the feedback, much appreciated.

In the house is only my wife and I, once in a while our adult kids come home for a visit. Our hot water cylinder is doing fine so I think I'll scrap the idea of installing instant hot water, just concentrate on getting the pipework sorted.

Thanks again everyone.

Pop! OS

eonsim

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#3017229 5-Jan-2023 10:58

Would agree it's better to keep the cylinder or if it was bust switch to using a heat pump cylinder. With the way things are going and the planned phase out of gas it's not a good 'investment' to be putting in gas appliances.

If you want to reduce your hotwater costs with the current system there are a few things you could consider.

1) If the hot-water cylinder isn't on a ripple control power circuit potentially look at having that done (not sure if this is still offered), controlled power tends to be noticeably cheaper than standard rates

2) Get a timer installed on the hotwater cylinder (assuming the cylinder is insulated and a decent size) circuit then switch to a electricity plan that offers lower overnight or off-peak power prices for example Flick, Electric Kiwi or Octopus in this setup could reduce the hot water cost by 20-40% (likely 10-15% savings on your total power-bill).

3) If not planning to move in the next 5-10 years get solar power installed and then setup to power you hotwater with either a timer or diverter, once that's done it will pretty much wipe out your hotwater costs (typically ~30% of power use) plus you'll have solar to reduce the remaining power bill.

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