I’ve said nothing so far… cause you guys have this well in hand. But…
Solar water heater has by far the best return on money. But that’s on an annual basis. When you’re in the middle of winter and your power bill doubles or triples (as it does) because of the increased water heating, the heat pump is the winner.
If you keep the existing tank and retrofit a heat pump to it, you always have the backup of the existing element. You can also connect it through the heat pump, which allows the heat pump to activate the element if ambient is low and your COP drops, or to manually “boost” the temperature.
Price-wise they are pretty similar. A good solar water heater is 15k to 20k. A 3.5kW (900W actual use) heat pump is around the same price. Remember you need to factor in the extras, copper piping, valves, lagging, the retrofit kit (which replaces one fitting on the geyser to allow the hot water to be fed in there). And copper is not cheap anymore. It adds a few thousand to the bill. But once it is installed, it is a real pleasure.
Prices I got a few months back, Geyserwise with panels, heat pumps, you name it, averaged around ±R25-R30k all in.
We have 3 geysers, so it becomes a very steep “investment” to save money in winter.
Hence my extreme reluctance.
End Result … I’m not paying for electricity anymore as I have paid my share for life. The rest can have all the hot water they want, have anything installed they want, as long as I don’t have to pay a cent.
Sorted.
EDIT:
Some background that lead to the above …
“Geyserman”, can we shower, what is the temp. #($%# - you have a App!!
“Geyserman” is there solar power, can we switch the geyser on? #($%# x 2 - look out the window … look at the display!!!
“Geyserman” has retired.
Note, it was an epic “battle” for days I tell ya! Epic. But I won in the end.
Exactly … “they” come to you because they are too lazy to look at all the tools “they” have been provided, for "their’ education and benefit.
And it starts small, one question once, then again, and again … till you have become “Geyserman”. You have become the geyser, the geyser has become you. You know the temp by looking into the distance. The oracle of hot water supply.
We have solar systems, there are rules, follow the rules and save a ton IF you educate yourself, train yourself … or pay the damn bill yourself.
This I understand is because in the middle of winter your solar system falls short due to a large increase in demand coupled with a reduced energy supply. But what if you sized your solar system for the worst case scenario??
Well, that would mean a greater capital expenditure that while used in Winter, may be redundant during summer and therefore also the best return on money.
Adding more panels would be my go-to position, but I am not under any illusion that it may not be the next best rand spent.
On the other hand, it does seem like the most universal deployment of funds.
I could spend Rx K extra on one appliance and Ry K extra on another and so on to minimize my solar dependency, but those solar panels last 25 years, and those appliances don’t.
Somewhere along the line, the extra K that can offset against any energy appliance does seem a more attractive go-to solution.
Well this is quite the debate:-) @plonkster where do you stand on the parallel in another multi ii 3kva vs sell my 3kva gx and get a single 5 or 8 (not liking the 8 because can’t parallel them and good grief why would I need to)… Any thoughts on this group on pylontech vs freedom won?
Indeed! A colleague of mine who worked for Eskom decades ago said they design a transmission line to have a 10% loss which they had found to produce the best ROI.
The same applies here I guess?
Remember the 5 is actually 4kW and the 8 is 6.5kW.
A small house can easily overload a 5. (I have a Phoenix 5 on a granny flat).
The older 8’s could parallel, the new ones not.
I also have a 2 x 8’s in parallel system and they have always behaved.
That is a small sample size, but I am happy after a bout 3 years or so.
The ability to parallel is a top selling point for Victron systems, which leads me to think that newer 8’s hardware will be updated sooner rather than later.
I think I’d explore the option of a 5 Multi plus a smaller 3.6kw Solis coupled with an export preventing CT downstream. That could give you up to 7.6kW on a sunny day and 4kW at night.
Hi, I’m probably late to the party, but I would not go for solar warm water in the roof. I have one currently on my roof.
My 5cents:
I’ve tracked my system to the T good old excel and VRM and a couple of formulas!
So I can, without a doubt, tell you, that in the Strand where I stay, mid-April to mid-September is when the Solar Geyser does not perform.
I also have just under 5kw of solar panels. And in the winter, 22 June ( round that time.(Sun never shines when you want to take measurements!)), I got just over 3kw max.
Why I’m telling you this? Because 4 extra panels will be less than what a proper solar Geyser or heat pump will cost, and you get more benefits from the extra Panels, ie, run your aircon, and bake some lekker Bobotie in the winter. Man, having too much free electricity in the winter will be awesome!!
I currently only have an MP2 3000va. But having a bigger system will be better, but then, as some have pointed out already, you will need more panels.
If you asked me 5 years ago I would have said 2 x 3kW. If you ask me today, I say upgrade to a 5kW. I have a preference for things that are simpler, and parallel setups are not
There’s actually many factors that you need to consider, roof orientation, available roof space, current geysers.
For jhb winters, most things don’t work so well because winters are just cold. Except maybe solar PV if you have north facing panels as we generally have clear skis for the majority of winter.
In winter, tubes raise the temperature in my 200l thermosyphon tank about 20 degrees. That’s not really enough as incoming water is super cold.
My 5kw heatpump takes twice as long to heat water in winter than in summer and will struggle to get the water to 55 degrees.
I did both as a diy in 2020 and can’t remember exactly how much I ended up paying but probably around 15k each, including the geyser for the tubes. The heatpump was 10k then and the tubes and manifold and stand about the same. Friend got a quote recently and it’s now about 25-30k for a heatpump / evacuated tube fully installed.
The tubes don’t need maintenance and the heatpump needs a clean and flush yearly. I have a big blue filter system so that helps a bit with not clogging the heatpump strainer. Jhb water infrastructure often breaks and the amount of muck that comes into the line is sometimes shocking.
Problem is the heatpump has a limited lifespan and most manufacturers will give a 5 year warranty. If you are unlucky that’s a cost of 25k that lasts 5k which isn’t worth it. Some installers will also make you do the yearly services which add to the costs.
So if you have the north facing roof, rather get extra pv and additional geysers for storage. East / west panels work great in summer but are really poor for winter.
Haha, I’m lucky. My battery has a big SOC display so my wife just looks at the battery screen (it’s right in the scullery close to the DB) and decides if she can turn the geyser on or not by herself. So no “Geyserman” in our house.
I refuse batteries to be used for geysers, as there are 3. “They” want that, I can import again for “them”, just EFT the funds first … then some more panels and a bigger wattage inverter.
We work on what the panels can do, and it works like a charm IF one looks at the display, on your phone or a web browser. Damn man, just look outside the window …
Bad weather days, so it costs a few bucks. Who cares. Geysers are not THAT important as some would like to make them out to be. #DayZero taught us all a lot.
Just remember the lessons I keep on telling “them” … a shrug, rolling shoulders, eyes focussed on the horizon shaking head to the rhythm of Rammstein playing … vaguely aware of mouths opening and closing Bitching and Moaning about “what is the temp”. Open the damn tap he thinks silently and walks away.
Dude, I am reminded of that bloke who ended up in hospital with a golf club up his rear end, and upon the matter making it into the legal realm and hearing the wife’s whole tale of how things go in that house, the magistrate apparently accepted the woman’s explanation that her husband did indeed sit down on the wretched thing by accident.
Ok you guys have convinced me… in interest of self preservation… (who knows what you might “sit” on if you’re not careful!)
leave the geyser as is:-P get a big inverter and many lots panels (the money saved from any/all conversions on the geyser should help)… feed excess solar back into the house so it can assist with the geyser and the pool…
