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Good day

Just to answer a couple of Q’s 

The Geyserwise pv conversion is an easy DIY installation if you are a handy type of guy. 
it works very well in overall reaching anything between 20-35 degrees per day. 
AC part of element can be 1500w for back-up. And no maintenance.

Tube collector system will be cheaper than the pv system but more work and suggest you use a professional for that as you can encounter some issues like reverse syphoning and wrong pump installations. 
(Note!! Don’t go flat plate route)

Then we have the heat pumps, over the last 11 years I have seen that heat pumps last anything from 4-6 years 6 years and maybe longer were the ones that was serviced every year ( personally not a heat pump fan but will do one with a tube collector as Hybrid )

lastly in terms of monthly bill % on Geysers! I found that it could be anything from 20-50% of monthly bill. 
switching your geyser with a timer or just 2 people it can be as above mentioned 25-30% but family of 4 easily 40% atleast, family of 5 easy 50%.
 

Tube or pv conversion easy 65-90% saving on the hot water. 

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  • 2 weeks later...

I am looking at this Geyserwise PV option at the moment.  A lot of the information available points to the PV solution being more expensive. However, I have been quoted just over R15k for the system (not installed, but I can DIY). Quote includes 3x 375W Candadian Solar panels. This price seems reasonable in comparison to other options at the moment.

My concern though is, will it heat the water quick enough during the day? My intention would be to heat it hotter than I need it during the day, my wife shower and kid bath in evening, and I could hopefully still be able to shower in the morning.  We also wash bottles and dishes 2 or 3 times per day. No appliances draw hot water.

The usage pattern wouldn't really make a difference with any solar option.

Current usage (winter, Pretoria) is 11kWh average per day on my 3kW 200l geyser, based on the usage pattern described above.

 

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@Craigm I am no expert, but the Geyserwise PV system is specified so that it normally heat your geyser in around half the day. So if all conditions are good your tank should be heated by midday(ich).

However it is never just so easy. It depends on the sun your house receives, the weather, your water usage, geyser size and your house efficiencies (long distance from the geyser to where you use the hot water). 

Do the following test: switch your geyser on around 11am for 3 hours and then switch it off. That should be enough to heat the water to temperature. 
Now use your hot water as described above and see if it last. 

This is what any solar geyser will give you. You get the water heated during the day while the sun is shining. In winter there is less sun and in summer there is more. 
When you use hot water in the evening it is replaced with cold water. During the night this cold and hot water does exchange heat between the layers in your geyser giving you not so hot water in the morning (no matter how much you insulate your geyser as the cold water is already inside).

So in practice you will see that if everyone showers in the evening, or everyone showers in the morning a solar system will work fine. 
If some people shower in the evening you will need to use electricity to heat the water for the morning shower person to feel happy.


PS. This is true for any solar geyser system. 

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Posted (edited)
1 hour ago, Louisvdw said:

If some people shower in the evening you will need to use electricity to heat the water for the morning shower person to feel happy.
PS. This is true for any solar geyser system. 

I think one can safely say that you need a backup heating system since your solar geyser will not work for you at all times.

Edited by Richard Mackay
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17 minutes ago, Richard Mackay said:

I think one can safely say that you need a backup heating system since your solar geyser will not work for you at all times.

Yes a few weeks ago our flatplate collecter had cracked a pipe . Don't know why the pump did start up on 5 degrees and you could see the temperature change. I have replaced it with Kwikkot vacuum tubes . Even the vacuum tubes need some assistance from the geyser element in winter . Don't no why they don't they fix these flatplate radiator . Had it at the factory no guarantee and no repair . Did repair it with little effort . Must get rid of it .

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Thanks so much for all the info thus far.  For me currently Flat plate seems the best option.  It is cheapest and safest.  The Geyserwise is really nice but according to my maths (might not be 100% accurate, but should be a good estimate), the geyserwise PV system will not get the geyser warm enough during then day, thus ending up paying Eskom more.  I have attached my maths, should anybody be interested...  For me the ROI on a Flat plate is around 3 years, even less if Eskom keeps messing up like they are doing right now. 

The most expensive part is the installation, as the going rate in the Lowveld is around R8k for a days work.  If you are up to installing a PV geyser system yourself, any other solar geyser shouldn't be that much more difficult to install.  

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I was given a link to this forum by Richard Mackay who thought I would be interested in the topic. After reading through the posts it would appear that no one on this forum has used, or owns, the Geyserwise product.

We lost our house in the 2017 Knysna fires but rebuilt on the same site in 2018. In the process, having always being interested in the solar topics, I decided to invest in the Geyserwise system for the new build. I have found, over the last two years, that the system does what it says on the box!

The installed system is as follows:

1) Panel orientation, North East

2) Panels set flat on the roof with a pitch of 30 degrees.

3) Panels, Renesola standard 250 watt, 3off.

4) Geyser 150l Kwikhot mounted vertically on South wall.

5) Standard geyser blanket fitted.

6) Element Geyserwise dual AC2.2kW/DC(8-72volt)

7) DC element set to a maximum of 60 degrees.

8) I have installed a voltmeter and ammeter on the DC input to the geyser so that I can see what is going on.

9) Electricity availability charge roughly R4.00 per day.

10) Electricity charges are roughly R2.00 per kW.

My personal details are:

1) Retired.

2) 2 persons in the house.

3) Hot water is used for showering(no bath in the house) , generally once a day in the evening. hand washing etc when necessary and sink duties 2 times a day. We have no dishwasher, never have had.

4) No domestic help.

5) Cooking is carried out using a combination of induction hob combined with two gas burners and a double oven. My wife does a fair amount of baking.

6) We have two cooked meals a day, full English breakfast and lunch. We do not eat out a lot.

7) There is one large fridge/freezer unit.

8) All lighting is LED.

9) We have no electric space heaters. I have tried to insulate the new house as well as possible and our climate is fairly mild.

10) I have a number of fair size machines in my workshop.

I am sketching this all out as a previous poster has mentioned, quite correctly, your power consumption depends entirely on your lifestyle and without this information you cannot make an informed assessment! Also, as someone has posted the solar salesmen are salesmen….

Because of my interest in solar water heating I kept a detailed record of power consumption in the previous house. The long term average was 13kW per day.

With the Geyserwise system installed our household power consumption is now between 7 and 8 kW per day during summer and 9 to 10kw per day in winter. From the above detail I am saving approximately R5.00 per day in winter and R9.00 in summer.

In retrospect I would consider an additional panel to support the winter power generation. This power would however go to waste in summer?

 

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