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Measureing power used by my geyser


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#1 Violater

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Posted 29 March 2011 - 04:02 PM

I'm considering getting a heat pump or solar geyser, but first I want to figure out how much hot water I'm actually using.

What's the easiest way to connect a meter onto the geyser so that I can measure the amount of power it would use in a month?
Then I'll decide if the potential savings would be worth it.
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#2 BadBoyTazz4Ever

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Posted 29 March 2011 - 04:11 PM

Maybe give this a try: Energy Calculator

or if you want more comprehensive calculators select one from the right: eskom
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#3 Pyro

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Posted 29 March 2011 - 10:49 PM

That's not exactly the most scientific calculator :/

So it doesn't matter if you fill one bath or two or even shower, as long as you have low-flow shower heads :p
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#4 c0d3r

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Posted 29 March 2011 - 11:13 PM

The geyser is the biggest user of power in a home. Turn the geyser off for a month and check what the difference in power usage is. I think even having your geyser on a timer (e.g. auto switch on at 8pm and auto switch off at 10pm) dramatically reduces it's power consumption.
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#5 BadBoyTazz4Ever

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Posted 29 March 2011 - 11:24 PM

Pyro i can't remember where but the 1st time i used that i read somewhere how they calculate that (maybe try the pdf 'manual'), the main reason they ask about the shower head is a water efficiant shower head can use up to 1/2 & even less water than a normal one & that makes a big differance.
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#6 BadBoyTazz4Ever

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Posted 29 March 2011 - 11:31 PM

C0d3r my previous boss put a auto timer on his geyser & he had it switch on at 0400 & switch off at 0600 and again at 1700 on & 1900 off and according to him it cut his power by 1/4...

Still wanna give thay one a try myself but after the 2nd day a forgott to switch it on & had to take a cold show i gave it up my entire power & water bill is R450pm-R480pm so i can not complain i avg about 400 units off power a month witch is already almost 1/2 of the area avg according to the account when they 'guess' my usage.
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#7 BadBoyTazz4Ever

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Posted 29 March 2011 - 11:42 PM

Sorry about double post i really hate Opera Mini Enhaced by Vodaphone... Any mods can remove the 2nd post & this post. Mobile skin doesn't have delete option.
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#8 c0d3r

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Posted 30 March 2011 - 12:00 AM

BBT: A saving of 1/4 the account is still a saving. And you don't have to do anything in terms of switching on or switching off the geyser. Extra money in your pocket for doing nothing sounds like a bargain to me.
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#9 Slasher

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Posted 30 March 2011 - 06:37 AM

Switching off a geyser does not always save money. Remember, Eskom use the ripple system already - As a result of this, every evening between 8 and 10 odd we do not have warm water in our flat as it stands.

Another thing - Some of the newer geysers are extremely efficient and well isolated. Heat loss is a minimum. Think about it - what takes more energy - heating 200l of water from room temperature to boiling, or just keeping a very well isolated tank of 200l water at a constant temperature?
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#10 Violater

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Posted 30 March 2011 - 07:13 AM

Thanks for the replies guys

Switching off a geyser does not always save money. Remember, Eskom use the ripple system already - As a result of this, every evening between 8 and 10 odd we do not have warm water in our flat as it stands.

Another thing - Some of the newer geysers are extremely efficient and well isolated. Heat loss is a minimum. Think about it - what takes more energy - heating 200l of water from room temperature to boiling, or just keeping a very well isolated tank of 200l water at a constant temperature?


Well that's what I'm thinking - I'm pretty sure my geyser is already so well insulated that it doesn't lose almost any heat. I doubt it would even reach room temperature if it was switched off for a day - thus I can't imagine saving anything as is should use basically the same amount of power to maintain the temperature as it would to get it back up to the desired temperature.
Correct me if I'm wrong, but you'd only start saving once the water in the geyser has gotten to room temperature?
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#11 Pyro

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Posted 30 March 2011 - 08:59 AM

Pyro i can't remember where but the 1st time i used that i read somewhere how they calculate that (maybe try the pdf 'manual'), the main reason they ask about the shower head is a water efficiant shower head can use up to 1/2 & even less water than a normal one & that makes a big differance.


I get that it could be more efficient, but I'd be happier if they included it in more usable terms.

EG:

How many showers does your geyser supply in one day?
How many baths does your geyser supply in one day?


I assume they guesstimate this from the capacity.

---

As for geyser switches:

Keeping the geyser at constant temperature if it's well insulated doesn't require a lot of power. Heat loss is a function of the temperature difference and the effectiveness of the insulation.
You'd probably do well enough to cut the temperature to 60'deg if you want to make a saving. If you do put in a timer, your saving would probably be much more notable at night when the ambient temperature is much lower.

Constantly expecting your geyser to 'sprint' from low temperature to high temperature puts extra strain on the heating elements, possibly reducing the lifespan of your geyser.
This is especially the case if you time it to get warm just before you empty it, and then has to get warm again.

I still want to look into geyser blankets though...
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#12 BluePhix

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Posted 30 March 2011 - 09:48 AM

A good geysor should already be insulated, the use of an insulating blanket will make some difference probably where there is a great difference between the geysor and the ambient temp.

The best method to save electricity using the geysor is to keep it at a constant temperature as Pyro says, one of the main SA manufacturers Kwikot state that info here: http://www.kwikot.co...Information.php (Geysor FAQ's)

I checked a Life Cycle costing tool on a local website and the break even period of a Solar geysor for family of 3 living in Windhoek for example is estimated at about 7 years.

http://www.emcongrou... - Ver 2005.xls

Hope this helps.
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#13 Pyro

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Posted 30 March 2011 - 02:45 PM

Decent summary there by KwikHot, but I still want to kill a puppy every time people say kW instead of kW.h :(

Also - while lowering the temperature in summer is great for not scorching yourself at the tap, I recall a previous discussion about not lowering temperatures below 55deg, as that is the temperature at which the majority of bugs in the water will die. If you drop it too low, you're providing a nice breeding ground for certain organisms.
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#14 BadBoyTazz4Ever

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Posted 30 March 2011 - 02:51 PM

Slasher not all towns/houses have the Ripple system installed. My parents house in Witbank has it in but i don't know of anybody in PTA that has it on the geyser.

C0d3r with the timer installed i don't have to warry about it but till i decide to install one o have to do the switching & as such i most of the time forget to switch it on again & i don't want to go & spend R600 on the time till i know it will save me money. Now the 1st day is not a problem the geyser keeps the temp for about 4 showers but that 2nd day i want to kick myself for not switching it on again.

My geyser is set to 55*C...
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#15 Pyro

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Posted 30 March 2011 - 03:31 PM

Ah yes - it was Legionnaires' disease that was referred to.

* 70 to 80 C (158 to 176 F): Disinfection range
* At 66 C (151 F): Legionellae die within 2 minutes
* At 60 C (140 F): Legionellae die within 32 minutes
* At 55 C (131 F): Legionellae die within 5 to 6 hours
* Above 50 C (122 F): They can survive but do not multiply
* 35 to 46 C (95 to 115 F): Ideal growth range
* 20 to 50 C (68 to 122 F): Legionellae growth range
* Below 20 C (68 F): Legionellae can survive but are dormant


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#16 Oj0

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Posted 30 March 2011 - 04:34 PM

What's everyone's power bill for the month? I say a 25% saving is massive, it works out to R600 per month or R7200 per annum.
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#17 Pyro

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Posted 30 March 2011 - 09:49 PM

What's everyone's power bill for the month? I say a 25% saving is massive, it works out to R600 per month or R7200 per annum.


The last two months my electricity averaged about R320, if that was true all year round my total would be under R4k, so 25% would only be R1k pa.

Edited by Pyro, 30 March 2011 - 09:51 PM.

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