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12 hours ago, Gerrie said:

Is there any gas/electric combo kettle available anywhere? We have one kettle standing on the gas stove gathering dust and right next to it the electic one. When I have time on my hands, sometimes I use the gas kettle but I than feel like giving it a bit of a electric boost while the battery’s are just sleeping it off in the back ground.

Bad phraseology on my side, and I apologise for any confusion. 

I meant a kettle that you can heat on a gas hob. 

Increasingly I'm thinking  bottled gas is not that cheap compared to electricity, but there's no load shedding. 

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I think part of the problem with gas is to get efficient heat transfer. 
Last year I got one of those gas stoves that have build in fins for better heat transfer and it made a huge difference. 

You can see the fins at the botton of the pot in the the image at https://www.loot.co.za/product/xtreme-living-inferno-cooking-system/tkhg-5447-g000
Most gas geysers would have a similar concept as well.

 

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5 hours ago, Louisvdw said:

I think part of the problem with gas is to get efficient heat transfer. 

Exactly. An electrical stove is around 75% efficient in heat transfer (from electrical energy into the food). Induction is 85%. Gas is like 40% or thereabouts...

Boiling water in a kettle is darn near 100% efficient (if the element sits inside the water). Doing it with gas is again around the 40% mark. Gas geysers do a bit better, since they do have a larger heater core and the flames are at least somewhat shielded, but the thing has a chimney and a lot of hot gas escapes form the top, heat that was not absorbed by the water.

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Posted (edited)
8 hours ago, Peter Topp said:

This instant water to use and not standing water in a geyser.

So I have a tenant renting one of the units at the back of the property, and this tenant has now been gone for a month. Today I realised the potplants are dying, and decided to water them. Then I discovered little black-green blobs of some kind of living plant growing in the kettle. I'm too scared to open the fridge.

That kettle... I suppose that's the kind of bad stuff that grows in water tanks... 🙂

 

Edited by plonkster

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Posted (edited)

Q=mcdT  No way around it.  By lowering the hot water temperature you are lowering the dT but making m higer and using the same Q(energy)

Or said another way: Setting your hot water to say 45C you need to heat less but you use less cold water and thus more hot water and in the end you use the same amount of energy or gas.

So why do some save energy?  Most gas geysers can only handle a certain flow rate. Thus setting the temperature lower you can't use more hot water and just shower with less water.
The same can be achieved with a water saving shower head or just turning the water flow down in the shower.

Another saving comes from the heat loss from the hot water pipes to the environment.  The higher the temp in the pipes the more energy is lost to the environment.  But well insulated pipes and a short run between the geyser and shower will make this negligible. 

Edited by Pietpower

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I only had one instance where a gas heater (boiler in this case) was cheaper to run than electrical. It was because the client had a bulk supply natural gas line with a hugely discounted rate due to high usage.  Was actually cheaper than running cost of a heat pump system.

If you have natural gas pipe to your house then it will probably be cheaper than electrical geyser (doubt it will beat a heat pump) but I have not had one example of LPG being cheaper.  Only advantage imho is to be off electrical grid.

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About  4 years ago I installed an electric geyser to act as a dumpload. When my family is away I can get away without using gas. Hot water from geyser powered by PV and I use an electrical kettle in conjunction with a thermos, and cook on an induction plate. Now during lockdown I have my broom-flying mother-in-law to stay and in the interests of my own sanity have abandoned any ideas of trying to be frugal in our gas usage.

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Posted (edited)
On 2020/05/08 at 4:26 PM, Chris Hobson said:

About  4 years ago I installed an electric geyser to act as a dumpload. When my family is away I can get away without using gas. 

Is this dump load for an (old school) inverter to manage excess PV power?

Edited by Richard Mackay
spelling!

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