I am a newbie and have started down the path of trying to alleviate my 100% reliance on Eskom. One of the key components that almost everyone I have spoken to is to change the geyser from a standard electrical to one of the following:

• Retrofit solar
• Heat pump
• Gas

I did an electrical audit and my main house geyser (4 people plus kitchen) uses about 12kWh per day and my domestics geyser uses 5kWh. This is off a total usage for my house of 159kWh (so about 11% of my entire consumption). With this in mind I had the idea of fitting a solar collector with Geyserwise controller and Geyserwise circulation pump for the main house and then just a Geyserwise timer for the domestic quarters. Quote for main house retrofit comes in at over R17k from two supplier but I have no idea how realistic this is. I also don't know if a heat pump or a gas geyser would actually be better options than R17k on solar.

Not strictly related but I am using an average of 16kWh during the day and 18kWh at night. As I am investigating a solar array with batteries can anyone confirm my actual requirements? Some installers have suggested 8kVA Inverter with 7,92kW PV Panels + 20kWh Battery where others have said 4.6kVA Inverter with 4.69kW PV Panels + 10.5kWh Battery will do the job. Any comments / suggestions here would be very much appreciated.
 

Retrofit has the advantage that you don't need extra plumbing, or possible roof leaks. And you won't sit with a geyser which might burst in hot summers, or at least blow off hot water every day during the summer months. 

A heat pump is nice and economical but an expensive investment which might take a long time to pay off. 

Gas is, not yet, more economical to heat water than electricity. It is instant though and generally limited to about 55 degrees. But it's instant so you waste less cold water to run a bath. 

In my case I had a look at what my max load would be and concluded that 3Kw would be a good end point. I don't get to 5Kw often enough to justify the bigger inverter and extra panels (and my allowable PV roof space on the garage is too little). So I opted for 3KW and fitted a 2KW PTC element in my existing geyser. Our normal daily use float between 400 and 500W. The dish washer uses 3Kw, kettel 2Kw, and tumble dryer 2Kw. Neither of these are on at the same time. Our induction plates normally operate at 400W or 800W, sometimes 1300W. The geyserwise timer is set to 60 degrees (max temp) and comes on at 13:00 and goes off at 16:00. The geyser is always at 60 degrees by then, and about 55 degrees at 18:30 when we run a bath. My kids are still young so they bath in the same water just after us. So for now it works out fine. 

When they grow older I will consider installing a 2nd 150L geyser and retrofit it. The house roof have plenty space for panels but only 3x or 4x solar panels 320W would be sufficient. 

Thank you for your input SilverNodashi

Moose I would go retrofit evacuated tubes

If your geyser is less than 2 years old it might be solar compatible . 

16 minutes ago, Clint said:

Moose I would go retrofit evacuated tubes

If your geyser is less than 2 years old it might be solar compatible . 

If it is a 4.5 or 5 year old Kwikot, they have a 5 year warranty, retro fit it.

It is going to blow right, 5 years and 1 day (insurance claim) or 4 years and 364 days ... wait a day. 🙂

When the insurance pays out, ask for the money and  add a few rands and buy a proper solar geyser, like a Duratherm, with a 10 year warranty.

Our geyser is outside the house now, gatvol of the water inside when it bursts, no blanket, just as is and it keeps its temp wonderfully. You can feel the geyser on a cold wet winter evening, it is ice cold, water on temp.

Use it, or not. 🙂 

14 hours ago, The Terrible Triplett said:

If it is a 4.5 or 5 year old Kwikot, they have a 5 year warranty, retro fit it.

It is going to blow right, 5 years and 1 day (insurance claim) or 4 years and 364 days ... wait a day. 🙂

When the insurance pays out, ask for the money and  add a few rands and buy a proper solar geyser, like a Duratherm, with a 10 year warranty.

Our geyser is outside the house now, gatvol of the water inside when it bursts, no blanket, just as is and it keeps its temp wonderfully. You can feel the geyser on a cold wet winter evening, it is ice cold, water on temp.

Use it, or not. 🙂 

Thanks for the reply. The geyser is in fact about 10 years old and in my complex we are not allowed external geysers (estate rules) so not sure how this affects the info above?

On 2019/03/11 at 3:47 PM, Moose said:

I did an electrical audit and my main house geyser (4 people plus kitchen) uses about 12kWh per day and my domestics geyser uses 5kWh. This is off a total usage for my house of 159kWh (so about 11% of my entire consumption)

Hi Moose, this bugged me since yesterday, but only got around again to it now.

If your Geyser runs in the region of 12kWh per day it gets to around 360kWh per month.

Reason this bugged me is mine also runs on a constant monitor and run 6-8kWh per day (3kW element) and monthly around the 200kWh mark.

R

7 minutes ago, Riaanh said:

Hi Moose, this bugged me since yesterday, but only got around again to it now.

If your Geyser runs in the region of 12kWh per day it gets to around 360kWh per month.

Reason this bugged me is mine also runs on a constant monitor and run 6-8kWh per day (3kW element) and monthly around the 200kWh mark.

R

My current geysers don't have any sort of timer on them and the water is HOT. Are you suggesting my data is incorrect or that I should have much better control to reduce consumption?

Just now, Moose said:

Are you suggesting my data is incorrect

Not at all, just saying that what I read is you are consuming 12kWh per day on your geyser.

If you use 12kWh per day over a 30 day period, then 12kWh * 30days  = 360kWh for the month. (you mention 159kWh month)

Just scared you prepare for replacing/retrofitting for 159kWh and actual is more that double that.

(PS: My biggest reduction in consumption was by adding a timer, cheap and well worth it imo.)

R

37 minutes ago, Riaanh said:

Not at all, just saying that what I read is you are consuming 12kWh per day on your geyser.

If you use 12kWh per day over a 30 day period, then 12kWh * 30days  = 360kWh for the month. (you mention 159kWh month)

Just scared you prepare for replacing/retrofitting for 159kWh and actual is more that double that.

(PS: My biggest reduction in consumption was by adding a timer, cheap and well worth it imo.)

R

Thank you R - I was a bit unclear as I spoke about an average of 17kWh for both geysers per day (so 17x30 days = 510kWh p/m) and I then spoke about total usage of 156kWh per day  which is 12% 🙂

3 hours ago, Moose said:

I then spoke about total usage of 156kWh per day  which is 12%

Layman's 2c. Most often the geyser is one of the main consumers in the household so that's where you'd think to start. If the total usage is 156kWh, then I'd start looking at the other 88% first to see what can be reduced/saved/eliminated more cost-effectively. You'll need roughly 30kW of solar panels to cover that usage.

On 2019/03/11 at 3:47 PM, Moose said:

I am using an average of 16kWh during the day and 18kWh at night.

Or is it 16kWh +18kWh=34kWh per day. Not sure I understand. And is this before or after the 17kWh of the geysers are taken out of the equation?

On 2019/03/11 at 3:47 PM, Moose said:

Some installers have suggested 8kVA Inverter with 7,92kW PV Panels + 20kWh Battery where others have said 4.6kVA Inverter with 4.69kW PV Panels + 10.5kWh Battery will do the job.

The first set of numbers sounds closer to home. Assuming daily consumption is not 156kWh but 34kWh. On 7.92kW of panels, you'll get maybe 40kWh generation per day on average. Battery capacity of 10.5kWh won't see you through the night if the consumption is 18kWh. For that matter, check if the 20kWh is all usable capacity, or what depth of discharge is assumed. You may need more if you want to go off-grid. Unless the second group of guys understood you're using 34kWh-17kWh=17kWh per day, in which case the 4.6kVA inverter makes more sense.

8 hours ago, Moose said:

Thanks for the reply. The geyser is in fact about 10 years old and in my complex we are not allowed external geysers (estate rules) so not sure how this affects the info above?

No effect at all.

I just mentioned outside geysers as I got tired of waking up or coming home to wet floors because geysers decided to burst. 🙂 

Last geyser that burst, all the water went into the water tank. That 50l is inside the roof, with the overflow pipe into the gutter. 😉 

2 hours ago, The Terrible Triplett said:

Last geyser that burst, all the water went into the water tank. That 50l is inside the roof, with the overflow pipe into the gutter. 😉 

You lucky bastard. Mine sprung a nice jetting leak that went right across the pan onto the ceiling... until it took it out.

14 hours ago, plonkster said:

You lucky bastard. Mine sprung a nice jetting leak that went right across the pan onto the ceiling... until it took it out.

Been there done that. Now I insist that the water goes where I say it does. Ja ja, I know that sounds arrogant but there is a method behind my madness, as with the water into the gutter into the rainwater tank. 🙂 

It was like +-1kl before we found the problem.

1 minute ago, The Terrible Triplett said:

It was like +-1kl before we found the problem.

Again, you lucky bastard. We lost 3 kiloliter by the time ours was discovered. Which normally would not be a big deal, bit this was in the middle of the 50 liter pppd limits...

1 minute ago, plonkster said:

... in the middle of the 50 liter pppd limits...

Ditto ... same here.

Man I was smiling recalling the plumber's face having had to drill a big hole in the wall to take the pipe into the gutter. 🙂 

23 hours ago, Moose said:

Thank you R - I was a bit unclear as I spoke about an average of 17kWh for both geysers per day (so 17x30 days = 510kWh p/m) and I then spoke about total usage of 156kWh per day  which is 12% 🙂

Apologies - I have been studying the actual CSV the guy who did the clamping supplied and as he included totals (not marked as such) my total daily and monthly totals were totally incorrect.  Total average usage per day is actually 65kWh with both geysers using 17kWh and critical loads totaling 40kWh (16 during the day and 25 at night). On the night time usage it is 25kWh but this includes 3 x A/C's which seem to account for about 7kWh in total from 18:00 - 6:00 so more like 18kWh critical loads 24/7

So doing a bit more research I am now down to two options:
 

1. Gas geyser for both main house and domestic quarters. Pro's is that it is not TOO expensive and is not reliant on Eskom at all and we will have instant hot water which does not run out. Con's is we don't know what the price of gas will do down the line (oh and I have to have gas to run it so may be an issue depending)
2. Solar retrofit for main house and time for domestic quarters. Pro's is that it uses solar. Con's is that it is expensive (I've been quoted R17k to retrofit incl pump and timer), and ROI will likely be 3-5 years and it is STILL reliant on Eskom some of the time.

Anyone want to weigh in on the above?
Can anyone suggest an installer who can supply and install (I need to get a quote 1st) in Johannesburg North?

2 minutes ago, Moose said:

So doing a bit more research I am now down to two options:
 

1. Gas geyser for both main house and domestic quarters. Pro's is that it is not TOO expensive and is not reliant on Eskom at all and we will have instant hot water which does not run out. Con's is we don't know what the price of gas will do down the line (oh and I have to have gas to run it so may be an issue depending)
2. Solar retrofit for main house and time for domestic quarters. Pro's is that it uses solar. Con's is that it is expensive (I've been quoted R17k to retrofit incl pump and timer), and ROI will likely be 3-5 years and it is STILL reliant on Eskom some of the time.

Anyone want to weigh in on the above?
Can anyone suggest an installer who can supply and install (I need to get a quote 1st) in Johannesburg North?

Gas heats up the water instantly. There's hardly any cold water wastage. And you can bath / shower as often as you like, as long as there's gas.

With gas there will never be a ROI. You pay R2K to R3k for a geyser, another R3K for installation + COC and buy bottle or two. So let's say R6k. And then you pay for the gas every year. I know a few people with gas geysers and their mileage all vary but it seems a family of 4 using it for a bath could expect to refill the big bottles every 4 to 7 months and at whatever the gas cost. My 9Kg bottle's refill prices increase on average R20 per year. And some times I don't get gas cause some winters are extra cold, or extra long and supply has run dry for a week or two.

My own experience with gas geysers was that it can't heat more than a certain temperature, which I guess is based on the size on the geyser. i.e. how many heat pipes it has. And the hotter you go, the lower the pressure becomes. On a bath it's fine sine it just fills the bath, but on a shower it's rather annoying to unpleasant cause then you can't easily regulate the water flow and temperature. And the gas temperature adjustment sits outside.

 

A retrofit kit, as you say, is rather costly. And ROI takes a long time to reach. And, depending on your area, and bath / shower routines, you probably still need Eskom to heat up the geyser.

This is only a problem in winter though, and generally also only those cloudy days. Which, according to research is an average of 12 days for the Gauteng area, per year. The rest of the time it's hot. The safety valves blow steam off at 85 degrees, which I've seen happen many times while on a roof.  IMO this is the better long term solution though. A cheap retrofit just puts an MPPT charger + some panels on the roof and hook it up to the geyser element. Set and forget. Or you can pay extra and have a geyser timer installed as well. Geyserwise has a dual timer which can use both solar PV and eskom to heat up the element. Many people have mentioned, on general throughout the year their geysers are still between 50 and 60 the next morning. So if you prefer to shower in the morning, there's hot water. The downside is, you'll only enjoy one bath per day as it has to re-heat. 

With gas you can do it every time.

 

 

So, in short, use gas if you have a lot of people who need to bath  / shower on demand a few times a day. Use retrofit PV if you want to save money in the long run.

 

 

In both instances you could have faulty equipment a few years down the line. We had a gas geyser once that packed up, couldn't find spares to fix it, replaced it with another one. We had to (let) make slight changes to the pipes as the previous installer installed hard copper pipes between the geyser and the wall and the fittings weren't the same distance apart. The new installers moved the geyser up a bit and installed some flexible pipes in between so it could accommodate geysers with different spacing between the pipes.

My brother in law built a biogas digester, so they can make gas using horse and cow dung, to supplement their gas on the farm. Seems to work OK, just involves a bit of work.

HI 

I would suggest retrofit normal geyser to solar, and the  do auto swicthover to LPG gas geyser to remove escom wire to geyser. 

I have tried various methods, including heat pump, but heat pumps expensive AND require servicing, the gas are the cheapest heating post solar which are free post capex. 

A proper gas geyser called CT ( constant temperature heat water easily to 55 deg C, you dont need more as you will add cold water in any case) 

I think i know what i ma talking about, are a qualified plumper, gas installer and engineer ( ps i dont want work, i have to much) 

Regards C

 

 

On 2019/03/20 at 11:51 PM, TTfan said:

HI 

I would suggest retrofit normal geyser to solar, and the  do auto swicthover to LPG gas geyser to remove escom wire to geyser. 

I have tried various methods, including heat pump, but heat pumps expensive AND require servicing, the gas are the cheapest heating post solar which are free post capex. 

A proper gas geyser called CT ( constant temperature heat water easily to 55 deg C, you dont need more as you will add cold water in any case) 

I think i know what i ma talking about, are a qualified plumper, gas installer and engineer ( ps i dont want work, i have to much) 

Regards C

 

 

What should this sort of install cost? I have been quoted about R17k just for the retrofit and i think you can get a gas geyser for around R2,800 but then need the cylinders, certificate etc. 

I got quotes for around 12500 for retro fit with installation for a 150L with EV tubes. I am interested to know about the gas + solar option, doesn't seem like many offer this? 

12 hours ago, Moose said:

What should this sort of install cost? I have been quoted about R17k just for the retrofit and i think you can get a gas geyser for around R2,800 but then need the cylinders, certificate etc. 

For R2800 you only buy a geyser. Then you need to buy a bottle, regulator, pipes, bottle cage and get installation + COC done. Installation + COC is about R3500 last time I checked. Complete installation. IMO the retrofit option outweighs gas in the long run. 

On 2019/03/22 at 11:09 PM, SilverNodashi said:

For R2800 you only buy a geyser. Then you need to buy a bottle, regulator, pipes, bottle cage and get installation + COC done. Installation + COC is about R3500 last time I checked. Complete installation. IMO the retrofit option outweighs gas in the long run. 

Thanks for the clarification.