Need a new hot water heater, seeing some advice please, thanks!

Forums › Home Workshop DIY › Need a new hot water heater, seeing some advice please, thanks!

Castlvaniafan

96 posts

Master Geek

#315363 8-Jul-2024 07:13

I've got a low pressur hot water heater in my attic which has done a decent job but is past its life span and needs replacing. I live in Wellington and typical Welly style I don't have much space outside, I do have a small corner outside but have to weigh up if it's worth taking it up with a hot water heater.

As I slowly upgrade my systems in the house I'm going to lower carbon footprint and lower power options with intention to completely remove gas (stove is the last thing now).

I just had a basic question as I'm not really familiar with LP vs Mains. Reason I ask is, if I have free space in my attice and very limited space outside. I'm considering just sticking with LP. My existing taps can take mains pressure though, just inspected all them and they are ceramic inside.

What is the advantage of going from LP to Mains?

And then I have a question about heat pump hot water heaters. As I'm weighing up the benefits of having an external heat pump water heater versus the space it's going to take up

Anyone in Wellington have one outside? How's the performance in the cold weeks like last getting down to 4-6* overnight?

Thanks!!

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#3257240 8-Jul-2024 07:47

High pressure hot water gives you better showers and better hot water pressure out of your Taps. I highly recommend it. I upgraded from low pressure about a decade ago and it was a great decision. We just replaced the cylinder, not much else had to be done but we already redoing the bathroom.

johno1234

2606 posts

Uber Geek

#3257246 8-Jul-2024 08:25

My next HWC will be a heat pump unit. Size of a small refrigerator, can sit outside, and will work down to -15 degrees ambient pushing out 55 degree water. Can be indoor or outdoor single unit or split unit.

As mentioned above - LP showers are very dribbly IMHO and turn flat cold as soon as anyone in the house turns on a hot water tap. HP will seem like an absolute luxury but beware if you have teenagers; They treat the shower as a standup spa and will use up a lot of power. Another bonus for heat pumps which are very very energy efficient.

Castlvaniafan

96 posts

Master Geek

#3257251 8-Jul-2024 09:17

johno1234:

My next HWC will be a heat pump unit. Size of a small refrigerator, can sit outside, and will work down to -15 degrees ambient pushing out 55 degree water. Can be indoor or outdoor single unit or split unit.

As mentioned above - LP showers are very dribbly IMHO and turn flat cold as soon as anyone in the house turns on a hot water tap. HP will seem like an absolute luxury but beware if you have teenagers; They treat the shower as a standup spa and will use up a lot of power. Another bonus for heat pumps which are very very energy efficient.

I wonder if there's any option to limit the constant flow of hot water on the newer heat pump water heaters that have some technology inside. I just timed my partner shower and it was 25 minutes..

Spyware

3718 posts

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#3257259 8-Jul-2024 09:29

Mercury recommend cutting showers to 4 minutes, Pulse Energy recommend getting gym membership.

Spark Max Fibre using Mikrotik CCR1009-8G-1S-1S+, CRS125-24G-1S, Unifi UAP, U6-Pro, UAP-AC-M-Pro, Apple TV 4K (2022), Apple TV 4K (2017), iPad Air 1st gen, iPad Air 4th gen, iPhone 13, SkyNZ3151 (the white box). If it doesn't move then it's data cabled.

BlargHonk

135 posts

Master Geek

#3257270 8-Jul-2024 10:08

I wonder how well a Standard HWC with Solar PV input stacks up against a Heat Pump HWC?

tweake

2214 posts

Uber Geek

#3257287 8-Jul-2024 10:39

Castlvaniafan:

I've got a low pressur hot water heater in my attic which has done a decent job but is past its life span and needs replacing. I live in Wellington and typical Welly style I don't have much space outside, I do have a small corner outside but have to weigh up if it's worth taking it up with a hot water heater.

As I slowly upgrade my systems in the house I'm going to lower carbon footprint and lower power options with intention to completely remove gas (stove is the last thing now).

I just had a basic question as I'm not really familiar with LP vs Mains. Reason I ask is, if I have free space in my attice and very limited space outside. I'm considering just sticking with LP. My existing taps can take mains pressure though, just inspected all them and they are ceramic inside.

What is the advantage of going from LP to Mains?

And then I have a question about heat pump hot water heaters. As I'm weighing up the benefits of having an external heat pump water heater versus the space it's going to take up

Anyone in Wellington have one outside? How's the performance in the cold weeks like last getting down to 4-6* overnight?

Thanks!!

of course the advantage of mains hot water is decent showers, speeds up washing machine filling etc. disadvantages is usually cost. you will need to adjust shower mixer and possibly washing machine. having gone to mains recently, i recommend it.

heatpump hot water really depends on how much hot water you use. the lower cost of hot water vers the higher machine cost. also you can get spit systems, so you can have the tank inside and the heat pump part outside.

Castlvaniafan

96 posts

Master Geek

#3257292 8-Jul-2024 11:20

BlargHonk:

I wonder how well a Standard HWC with Solar PV input stacks up against a Heat Pump HWC?

My eventual plan is to put the heat pump heater on solar.

Kickinbac

412 posts

Ultimate Geek

#3257299 8-Jul-2024 11:45

Castlvaniafan:

johno1234:

My next HWC will be a heat pump unit. Size of a small refrigerator, can sit outside, and will work down to -15 degrees ambient pushing out 55 degree water. Can be indoor or outdoor single unit or split unit.

As mentioned above - LP showers are very dribbly IMHO and turn flat cold as soon as anyone in the house turns on a hot water tap. HP will seem like an absolute luxury but beware if you have teenagers; They treat the shower as a standup spa and will use up a lot of power. Another bonus for heat pumps which are very very energy efficient.

I wonder if there's any option to limit the constant flow of hot water on the newer heat pump water heaters that have some technology inside. I just timed my partner shower and it was 25 minutes..

I wonder the same for my teenagers. I think one lies in the bottom of the shower and goes to sleep! The other we can't get to have a shower! We have a hot water cylinder so at least it eventually goes cold. If it was continuous gas, urgghh!

You could install a solenoid valve on the hot water on a timer. But doing that to your partner could be means for divorce though! Sometimes you just have to suck it up and accept it for what it is.

tripper1000

1600 posts

Uber Geek

#3257485 8-Jul-2024 16:26

Castlvaniafan:

I wonder if there's any option to limit the constant flow of hot water on the newer heat pump water heaters that have some technology inside. I just timed my partner shower and it was 25 minutes..

Heat pumps cylinders don't limit/control water flow :-( They do run much more efficiently when set to a lower temperature which in turn means the cylinder runs out sooner :-)

If you are on water tanks, there are add-on flow monitors for water pumps. If the water runs for 30 minutes straight (or some other pre-settable time), it assumes you have a burst pipe, or forgot the sprinkler, or have a stuck float valve and shuts off to save draining the tank/flooding. Stays off until a power cycle. A friend with teenagers found this to be an excellent solution that the parents couldn't be villainised for.

Jase2985

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#3257486 8-Jul-2024 16:29

BlargHonk:

I wonder how well a Standard HWC with Solar PV input stacks up against a Heat Pump HWC?

well the first option will be more expensive.

It would be hard to justify swapping to a Heat Pump HWC if you had solar, if you didn't need to upgrade your HWC already. The payback period would be awfully long.

Kickinbac

412 posts

Ultimate Geek

#3257569 8-Jul-2024 18:42

Castlvaniafan:
BlargHonk:

I wonder how well a Standard HWC with Solar PV input stacks up against a Heat Pump HWC?

My eventual plan is to put the heat pump heater on solar.

There are good benefits to this. If the HWHP is programmed to run during the day, from say 10am to 4pm you can maximise free power from solar and not sell it back to the grid at a cheaper price than you’d pay to heat water when the sun goes down.
A HWHP has better COP during the day when ambient temperatures are warmer.
The HWHP using less kW to heat the water so your PV system doesn’t have to be as large.
You do need enough storage to get you through to the next day.
This is popular in Australia but they have other incentives rather than cost saving to heat with electricity as their power grid is no where near as renewable as ours. They get rebates to buy HWHP to get off gas.

sir1963

3186 posts

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#3257596 8-Jul-2024 20:19

Castlvaniafan:

I wonder if there's any option to limit the constant flow of hot water on the newer heat pump water heaters that have some technology inside. I just timed my partner shower and it was 25 minutes..

25 minutes...oh bliss...

Next on my hit list will be a nice deep bath I can soak in while reading a book and drinking a glass of red wine...

Handle9

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#3257603 8-Jul-2024 20:41

Castlvaniafan:

I wonder if there's any option to limit the constant flow of hot water on the newer heat pump water heaters that have some technology inside. I just timed my partner shower and it was 25 minutes..

If you want to restrict flow you need a flow restricter. It does exactly what it says on the tin.

A hot water heater heats water, that's all.

Neither of those things will enable you to have a conversation with your partner about their water use.

Handle9

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#3257605 8-Jul-2024 20:43

Jase2985:

BlargHonk:

I wonder how well a Standard HWC with Solar PV input stacks up against a Heat Pump HWC?

well the first option will be more expensive.

It would be hard to justify swapping to a Heat Pump HWC if you had solar, if you didn't need to upgrade your HWC already. The payback period would be awfully long.

I'm still pretty dubious about the economics of hot water heat pumps in a lot of cases. You need to use a decent amount of water to make them stack up, especially when they just won't have the lifespan/low servicing costs of a resistive hot water heater.

catdog

108 posts

Master Geek

#3257629 8-Jul-2024 23:21

Castlvaniafan:
I just timed my partner shower and it was 25 minutes.

I purchased these thermometers/timers for our showers. It won't turn the hot water off when it has been too long, but it does show how many minutes (and hours!) the water has been running for when you're in there.

It's powered by the water flowing through it, so slightly acts as a reducer on mains pressure (I don't think it would work well on low pressure). Only downside is it does make a whirring noise.

Make sure to select V2 which has the thermometer and timer function as V1 is only thermometer.

https://a.aliexpress.com/_mN0kZZO

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