Most Efficient Electric Geyser Replacement

[Deez]

Good Day Fellow Members

I am looking to replace or retrofit my existing electric geyser and am busy with research  so I would appreciate any feedback provided.

1) Objective

• Ensure supply of hot water for prolonged outages (> than 4 hours caused by load shedding) as our infrastructure grid has deteriorated and we experience regular, long delays.
• Cut electricity costs.
• I would prefer to utilise my current geyser and convert it instead of replacing it completely (unless there is a cost effective alternative).

2) Geyser Specs

• I have 3 x 200l geysers but for now I am looking at just converting 1 of them unless there is a cost effective way to do all 3.
• These are Kwikot geysers so I assume that the element is the standard 3kw.

3) I am going to install a solar system next week with the following specs

• 6 x 400W Solar Panels
• 5kw Deye Inverter
• 5kvA Li Batteries

I have researched numerous solutions including gas geysers, integrated solar geysers and retrofitting the current geyser. I have also followed numerous threads on this forum but I am still undecided. 

Any advice with possible configurations will be appreciated.

Thanks!

Deez

 

[Tariq]

2400 watts of pv power is not going to be enough, I have 4260 watts of solar panels, my geyser is 200 litre fitted with a 2 kW element ( heat it to 70 degrees once a day with pv ONLY ), it takes an average of 5 hours to heat the geyser to 70 degrees, as it is winter, i just barely get my batteries charged to 100 % ( use batteries during the night , to cut down on return on investment )

[Gerrie]

On 2021/06/09 at 9:21 AM, Deez said:

I would appreciate any feedback provided.

My two geysers are configured in a “It will never work” way but it is something that can also work. I ended up doing my own install to make sure every thing is insulated and no skimping of materials. I doubt anybody else has the same system but am curious if there are others like this.

Few years back I decided to go the solar route. Starting with the geyser because of it being the thing that is responsible for about 45% electricity bills. I did not opt for the retrofit flat plate but a complete solar solution. I kept my existing kwikhot 150liter geyser as a spare. Not wanting to remove it because I was a bit wary of solar geyser promises. It seemed like a waste to remove a good working electric geyser for no real reason. I did however install two new shutoff valves for this “to be spare” geyser on the “in and outlet” so that I could shut them and also drained the water. 

I then installed a 200ltr h/p evacuated tube geyser parallel over the spare geyser also with it’s own shutoff valves. So I can switch between any of the two if needed. 

The evacuated geyser been running more than two years now not needing the spare geyser until two months ago my solar geyser controller had a small problem that forced me to switch on the spare geyser and open it’s valves. Within 45minutes we had hot water again. 

I have been experimenting with the two geyser side by side in parallel 150ltr + 200ltr and think I will only revert back to the solar option in spring time when less hot water is required.

The result is surprising with plentiful of hot water even with all Eskom’s load shedding the last couple of weeks. During the day the solar heats up to about 70degrees and the kwikhot element geyser to 60 degrees the two geysers now mix hot water at the taps and the temperatures of both geysers does not drop much, even when one geyser is colder the hotter geyser adds the hot water in the mix. I am paying slightly more now in winter for Eskom but it is nice to not worry about hot water. I have since installed a inverter and think as I expand and spare pv becomes available to power the electric geyser with pv.

[Deez]

22 hours ago, Vassen said:

How are your 3 geysers connected. All in the same location or at different parts of the house. 
 

Where about do you live. Evacuated tubes struggle in winter unless you really overspec the system and then cover some tubes in summer. Heat pumps are costly and also struggle a bit in winter. There’s also moving parts that need maintenance. Also depends on whether you can do this maintenance by my yourself or if you need someone else to come do it which means more costs. 
 

Ive got an 200l thermosyphon evacuated tube system in series before a standard 150l liter. On my second 200l geyser, have a 5kw heatpump. I did both of these before I installed my solar PV system. If I were to do it again, I would just install a bigger PV array and increase my hot water storage and use the PV to heat the water during the day and use at night. It’s far more simpler, and probably more cost effective than a 20k heatpump install or a 15k evacuated tube install. 
 

So in your case, I would change the element on the geysers to 2kw and then just heat it during the day based on different timers. Also depends on how the 3 geysers are installed 

Hi

The 3 geysers cover different areas of the house. The main 200l geyser covers the main bedroom and the kitchen. 

As luck would have it, my 200l electric main geyser just burst! So I am deciding between replacing it with an electric geyser, retrofitting with a solar installation (either PV or evacuated tubes) or going gas.

It's interesting that every installer I have spoken to cautions against putting a 2 kw element in a 200l geyser!

I am leaning towards the PV installation with a Geyserwise/Gesyerworx system that will allow me to utilise electricity to get the required temps on cold/overcast days.

Thanks for the feedback.

 

[Deez]

1 minute ago, Vassen said:

@RyanG has the geyserwise PV system so I guess he can provide some first hand advise about it. 
 

Did they provide a reason? I don’t see how it can be a problem. The only concern is that it will take longer to heat the water which means it needs to run longer but my 200l came with a 4kw element which is too high for a 5kw inverter 

Yeah main reason they provide is that a 2KW wont heat up the 200l geyser.

[Rdelete]

9 minutes ago, Deez said:

It's interesting that every installer I have spoken to cautions against putting a 2 kw element in a 200l geyser!

@Vassen @Deez Exactly. I have three years experience on these. Geyserwise dont use a element in the element if you buy from them. This is the splab on them. Its a bakelite material I believe that does the heating

An immersion heater element that offers inherent safety and improved functionality over typical resistance-wire heaters. Our new technology utilises Positive Temperature Co-efficient (PTC) chips as the heat source.  You can even buy this for any geyser without all the PV stuff

https://www.geyserwise.com/products/elements/2200-w-ptc-ac-element/

 

So that would not hold true at all about a 2 KW. I always see the geyser as a large kettle. Would a smaller element in a kettle have a big difference. Say you put a 1800w in a 2500w after it broke??

[Deez]

3 minutes ago, RyanG said:

@Vassen @Deez Exactly. I have three years experience on these. Geyserwise dont use a element in the element if you buy from them. This is the splab on them. Its a bakelite material I believe that does the heating

An immersion heater element that offers inherent safety and improved functionality over typical resistance-wire heaters. Our new technology utilises Positive Temperature Co-efficient (PTC) chips as the heat source.  You can even buy this for any geyser without all the PV stuff

https://www.geyserwise.com/products/elements/2200-w-ptc-ac-element/

 

So that would not hold true at all about a 2 KW. I always see the geyser as a large kettle. Would a smaller element in a kettle have a big difference. Say you put a 1800w in a 2500w after it broke??

@RyanG

So if I understand your thread correctly, you would advocate putting in the new 2.2kw Geyserwise PTC element with a 200l geyser?

 

[Rdelete]

13 minutes ago, Deez said:

Yeah main reason they provide is that a 2KW wont heat up the 200l geyser.

@Deez the PV system has a dual element 900w DC and 1500w / 900w recommended for 150l and 2000w AC /900w DC for the 200l. The 900w heats the water via DC (PV) to a special MPPT controller to the PTC element. Yes it heats it. Even at 900w(200l). The day would start at 55C, then the morning people shower/ bath 26C - 30C. At the time I use the water 55C around midday, I am old school and shower quick, now at about 44C, come 3pm to 5pm back at 55C again.  I also have the 150L , works even better as its smaller at 900w naturally. This is winter

[Rdelete]

5 minutes ago, Deez said:

So if I understand your thread correctly, you would advocate putting in the new 2.2kw Geyserwise PTC element with a 200l geyser?

I would not be discourage from using any 2 KW, however the Geysewise has some positives on the PTC element. Either way dont be discouraged using a smaller KW element. I agree with Vassen. it will take longer to heat ,use less power but longer.

[Rdelete]

@Deez I was thinking about this topic. My geysers are covered by Home Loan insurance. Lets say they are not, and I have made no PV investment to heat the water. What are my options >> new Geyser. Yes but then a 150l > How do I heat it?? EV tubes. No thanks and pretty costly. PV Maybe but also costly ?? >>>best hot water ?? GAS?? Yes please. Yes yes. No Eskom, no power, far less dependency. The difference it made in our lives taking out the electric hob and Oven and putting in the Gas was Huge. Our gas usage is 19KG about every 4 - 5 months at R500 a cylinder refill. Endless no worries every during every load shedding. Even hot water for coffee on a whistle kettle. imagine a geyser that works on very little gas to heat water when required. Bye bye eskom completely

[Deez]

3 minutes ago, RyanG said:

@Deez I was thinking about this topic. My geysers are covered by Home Loan insurance. Lets say they are not, and I have made no PV investment to heat the water. What are my options >> new Geyser. Yes but then a 150l > How do I heat it?? EV tubes. No thanks and pretty costly. PV Maybe but also costly ?? >>>best hot water ?? GAS?? Yes please. Yes yes. No Eskom, no power, far less dependency. The difference it made in our lives taking out the electric hob and Oven and putting in the Gas was Huge. Our gas usage is 19KG about every 4 - 5 months at R500 a cylinder refill. Endless no worries every during every load shedding. Even hot water for coffee on a whistle kettle. imagine a geyser that works on very little gas to heat water when required. Bye bye eskom completely

Hi Ryan,

I am 100% on your page. My geyser is covered by insurance but I am considering using the pay out to convert to gas. I also have 4kw of installed PV cells with a 5kw Deye inverter.

Option 1 - Replace geyser and convert to Solar

• Replace Geyser with a 200l Kwikot geyser (covered by insurance).
• Replace 4kw element with a 2kw electric or PTC element.
• Install a GeyserWise or GeyserWorx system to "smart" control the geyser and switch seamlessly between DC and AC as required to maintain temperature.
• I understand that this wont get me completely off the grid but it will allow me to maximise the investment of my PV installation.
• Costs
  • Geyserwise = approximately R10k - lets say R11.5k with installation.
  • GeyserWorx = R9.3k with installation (add in a another R2k for a AC/DC element - still confirming with GeyserWorx whether this is required.)
  • Ongoing electricity usage will only be determined once installed and measured over a period of time.

Option 2 - Remove geyser completely and put in a Gas Geyser

• Remove burst geyser and install a 20L forced fan gas geyser
• Utilise the R6k pay out from the insurance comp to contribute towards costs of gas system.
• Complete decoupling from Eskom.
• Costs
  • Approximately R18k - R20k installed with a decent Paloma or Bosch geyser.
  • Therefore all in about 12k taking the insurance payout into consideration.
  • Cost of Gas to change a 48kg bottle every 2 to 3 months (R1350).

Conclusion

In my situation the installed cost works out to pretty much the same for both options with the gas heater slightly more expensive. The swinger will be the ongoing cost of gas vs the electricity utilisation I suppose.

Not a clear winner in my opinion except it you want to off the grid completely.

 

 

[Rdelete]

15 hours ago, Deez said:

Option 1 - Replace geyser and convert to Solar

You need Eskom and you will have cold water at night time load Shedding, or use up battery to heat water at 2am.

15 hours ago, Deez said:

Option 2 - Remove geyser completely and put in a Gas Geyser

You will never have cold water and never be reliant on Eskom. The 48kg are huge, even 19kg lasts long, Have spare like I do and  when one is empty I change to the other and have at three months to fill the spare.

[Buyeye]

Hi @deez I went with the change to a lower power element route and connect to a 5kw inverter with overspecced pv array.

 

If you go for a good size inverter like the deye 8kw or axpert max 7 kw then you don't have to change anything on your geyser just the source of electricity that heats your water. Then you don't have to worry about the insurance you just claim as usual.

[Deez]

2 minutes ago, Buyeye said:

Hi @deez I went with the change to a lower power element route and connect to a 5kw inverter with overspecced pv array.

 

If you go for a good size inverter like the deye 8kw or axpert max 7 kw then you don't have to change anything on your geyser just the source of electricity that heats your water. Then you don't have to worry about the insurance you just claim as usual.

Thanks Buyeye

I have decided for now to go with the 20l Gas Heater to have an alternative heating source for long outages. We are currently experiencing lots of long outages due to faults at Houtkoppen sub. 

I am going to change the elements on my 2 remaining geysers down to 3kw and will connect that to the next phase of my PV Array + inverter/battery set up.

[Rdelete]

24 minutes ago, Deez said:

I have decided for now to go with the 20l Gas Heater to have an alternative heating source for long outages.

Love this choice .....  Best choice I think

Edited June 22, 2021 by RyanG
Cost of Gas to change a 48kg bottle every 2 to 3 months (R1350), more like 4 to 5 months, You have to shower a lot to use 48KG this quick> we cook every night and use one to two furneses, lasts 4 months min

[Rehaan]

On 2021/06/22 at 2:49 PM, Deez said:

Thanks Buyeye

I have decided for now to go with the 20l Gas Heater to have an alternative heating source for long outages. We are currently experiencing lots of long outages due to faults at Houtkoppen sub. 

I am going to change the elements on my 2 remaining geysers down to 3kw and will connect that to the next phase of my PV Array + inverter/battery set up.

 

@Deez - Update on the 20L Gas Geyser? Did you install the Paloma?

 

How is the Gas Consumption? How long is 1 GAs tank Lasting you and what size?

 

 

[Deez]

Hi Rehaan

The final set up includes:

• the Paloma 20l geyser that has effectively replaced 1 of my 200l geysers;
• Gas stove, which has replaced by electrical stove;
• Supported by 2 x 48kg gas cannisters.

In summary, I am very happy with my choice for the following reasons:

1. Paloma is a very good brand and the unit is quiet, requires minimal maintenance and you are able to set the temperature very easily via a panel inside the house. Setting the temp lowers decreases your gas consumption.
2. The time taken for the water to heat up at the tap in on average 3 - 10 seconds.
3. The cost of each is 48kg gas cannister is approxmately R1300 and I get on average 1.5 to 2 months utilisation which represents a saving on my utility bill.

The water pressure is not as great as the electrical geyser but that only bothers my wife - not me :-).

I have also installed a bore-hole with a booster pump so I am completely off the grid for water. There have been no issues with the water pressure for the gas heater.

The configuration we went for is definitely the correct option.

Hope this helps.

Regards,

Deez

[Rehaan]

Hi Guys

 

I am deciding on the following :

Option 1 : Replace my Electric Geyser with a 26l Paloma

Option 2 : Removing the Element from the Electric Geyser and adding a Heat Pump

 

My Current Geyser Setup :

1 x 200l Solar Geyser with Tubes, Feeding into 1 x 150l Electric Geyser which feeds the house,

 

My Solar Setup :

2 x 5.5kw Sunsynk Inverters

2 x 3.6kw Pylontech Batteries

18 x 330 Solar Panels

I plan to add 1 more Battery and Maybe a Wind Turbine(A Whole new Topic).

The Idea is to go off grid or as close to off grid as possible and not to depend on Eskom.

 

My problem :

My Electricity Bill is currently 3k per month. Family of 6 + 2 Domestics, Everyone showers at different times, Hot water is being used for Mopping floors, Washing clothes, Dishwater, etc (its out of my control) Every time someone opens the hot water tap the geyser element kicks in, Unfortunately I cannot change the habits of how they use hot water, 

 

I should also mention that i have a Gas Hob and Gas Fireplace.

 

My Solution :

Option 1 : Let the Solar Geyser feed the Gas Geyser.

Pros - Hot Water on Demand, Hot water during Load Shedding, Saving on my bill,

Cons - High Gas Bill??? and??

 

Option 2 : Let the Solar Geyser Feed the Electric Geyser, Remove Element on Electric Geyser and replace with Heat Pump,

Pros - Saving on my Electricity Bill 

Cons - No Hot water during Load Shedding or Power Outages, Unless its connected to my Solar System but Will Probably drain my Batteries during the Evenings. Also it still uses some Electricity.

 

Please note - the Element on the Solar Geyser is Switched off.

 

Looking forward to the feedback.

 

 

 

 

 

Edited November 15, 2021 by Rehaan

[TimCam]

9 minutes ago, Rehaan said:

1 x 200l Solar Geyser with Tubes, Feeding into 1 x 150l Electric Geyser which feeds the house,

How many evacuated tubes do you have, and does the pump circulate the water through both geysers, or just the 200L?

What control system do you use for the solar geyser, and does it control the element on the 150L geyser too?

Have you thought of installing a PTC element in your 150L geyser, and running it off the inverters, as essential load, but controlling the usage.

https://www.geyserwise.com/products/elements/1500w-ac-element/

 

 

[Rehaan]

1 minute ago, TimCam said:

How many evacuated tubes do you have, and does the pump circulate the water through both geysers, or just the 200L?

What control system do you use for the solar geyser, and does it control the element on the 150L geyser too?

Have you thought of installing a PTC element in your 150L geyser, and running it off the inverters, as essential load, but controlling the usage.

https://www.geyserwise.com/products/elements/1500w-ac-element/

 

 

To be honest i am not sure how many tubes, i would guest 10 to 12 Tubes, will go onto the roof to check.

I don't think there is a pump installed,

Geyserwise to control the Solar Geyser, No controller or Timer for the electric.

I did consider installing the PTC Element and running it off the inverters, but the problem is i need hot water on demand so controlling it is going to be difficult, 

For example, my domestics shower @ 5.30am and again @ 9pm, my kids shower @ 6pm, My baby showers @ 12pm & again @ 6pm, My wife showers @ 10pm. I shower @ 9pm, This is besides the Taps running hot water for normal cleaning of the house.

 

[TimCam]

12 minutes ago, Rehaan said:

I don't think there is a pump installed,

If it's a high pressure solar geyser, and the geyser is installed below the tubes, it needs a re-circulation pump to pump the hot water out of the solar geyser manifold and down through the geyser. The Geyserwise should be controlling the pump depending on the difference in temperature between geyser and solar geyser manifold.

For a 200L geyser, I would suggest at least a 20 tube solar geyser.

What temperature does the solar geyser get too on a good hot day?

38 minutes ago, Rehaan said:

Geyserwise to control the Solar Geyser, No controller or Timer for the electric.

I personally have never used a Geyserwise, so don't know it's functionality, but if possible set ON timers from 4:30am to 06:00am, and 5:00pm to 10:30pm, and 11:00pm to 12:30pm. Also set a minimum geyser temperature of say 45 deg. C. This would require getting an element for the 200L geyser, or a geyserwise for the 150L geyser.

If you power the geyser from the inverters, more PV panels will help during the day.

[Pieter Lourens]

Dear All

I thought it well to share my experience.

I converted my 150l geyser to PV about two years ago and recently did the same for my 2nd geyser. The cost is about 10G a geyser.

The geysers are off the grid in the summer and consumes about 2kw in the winter. However, I heat the geyser to about 60 degrees and via timer switches that off at night. In the morning after the evening's usage the water is about 25 degrees. Multiple baths in a day will have a different experience. We are 2 people per geyser mainly having one bath a day.

Now that I have set the scene, this is the set-up:

- a Geyserwise ac/dc ptc element with flange, gasket and thermo pocket replacement to kwikhot geyser. Ps some have 5 others 6 holes for flange:

- link 2x PV panels to dc section of element, adding the needed safety eg fuse of course; the solar panels Volts/Amps configuration must meet the PTC element constraints, choose the panels well;

- link the AC side to DB box with a thermostat/relay controller.

And that is it :)

[Denarius]

From what I can see Geyserwise claims their element is slightly more power efficient than a normal element such as the kwikhot one.

[Pieter Lourens]

39 minutes ago, Denarius said:

From what I can see Geyserwise claims their element is slightly more power efficient than a normal element such as the kwikhot one.

I noticed many debates around this and will not argue for or against this.

I can say that the PTC element is a much larger element with much more surface exposed to heat the water. As such I would think there are more efficiency in a PTC element.

I prefer the PTC because it seems much more durable and the inherent characteristics suits my solution well. I throw dc energy at the element without fancy controls, hence less cost. As the element gets warmer the energy consumption reduces

With 800W of PV the temperature is maintained at about 60 degrees. PS temperature did reach 70 degrees once. Furthermore, my roof is north-east facing but does have full unobstructed sun.

[PeterW102]

Hi Guys

I have read just about every topic on Geysers, solar, etc.

I am in the same boat as many of you. The electricity costs are just too high these days.

This Geyserwise PTC DC element is actually very nice. Have a 150L Kwikot geyser and was wondering -

Will it be possible to drive this DC PTC element directly from a 48 Li-ion battery bank and then just charge the battery from 220V ? No solar involved. Surely the charge current will be less than the current directly being consumed by the element ?