Nickvdv

Thank you @GreenFields, @Scorp007 & @TimCam - I was previously looking at heat pump but didn't follow through. Got quotes towards the end of last year for a 3.6kW ITS heatpump for R 23k, 5.4kW pump for R 32k - including installation. Going with my initial estimates above of geyser usage being around 600kWh /month and a heat pump possibly saving 50% of that cost, it could approximately save 300kWh a month. That's an estimated saving of R 800 /month on grid power, not sure how to calculate it on solar panel yields seeing as the hot water needs are barely overlapping with the optimal period for solar energy generation. I suppose it'll partly save on grid power expenses, and partly on reduced battery usage. With an ROI of around 2 to 3 years for the R 23k installation when calculated on grid power costs it's perhaps worth considering. But how would it reduce the requirements for the solar array, seeing as those batteries would still have to be full to power it at night (and thus you'll need excess panels)? -- Off topic; @TimCam where did your friend buy the Hubble AM2 for that price? I was quoted R 31k for the 5kWh model. Cheapest I can find is R 30k at https://www.inverter-warehouse.co.za/products/hubble-am-2-5-5kwh-lithium-battery-1?variant=43525702189305&currency=ZAR&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gclid=EAIaIQobChMI7ezbpqS0_gIV0u3tCh1RmgjOEAQYASABEgKrgfD_BwE

Hi all, thank you for all the feedback, I really appreciate the time you've taken to respond. My takeaway is that the R 22k/R 30k might be better spent on additional panels + a lower wattage heating element, and rely on batteries or grid power (if batteries are low) to prepare hot water early mornings. The requirement would be to get an inverter which would allow to make the decision to use grid power for the geyser if batteries are below x percent. Optional additional battery if we still rely too much on grid power, but ROI calculation for that can be done afterwards depending on what the remaining grid power draw would be. I'll try to leave space above the current geyser in case we'd ever reconsider the EV solar geyser, but we'll leave that cost out for now. Thank you @mzezman, @Chris_S, @iiznh, @BritishRacingGreen, @TimCam and @cbrunsdon for your valuable inputs - much appreciated.

Hi gents (& ladies), I’m looking to install a solar panel array with the aim to reduce my dependence on grid power and Eskom’s tariff increases. I’m in doubt between including my current 150l electric geyser in the solar panel load, keeping it separate and pay R 22k for the conversion or replace it with a solar geyser for R 30k. We have a household of 4 adults and 2 kids, most of whom would like a hot shower in the morning or the evening (or both). The 150l geyser is sufficient, but it runs 4am – 10am and 2pm – 8pm to make sure there’s hot water available. I’m assuming my current daily usage just for the geyser would be close to 20, 25kW (assuming it’s not using 3kW for the full 12 hours it’s on). Average daily usage for the entire house over the last 6 months is 37kWh, with the big spenders being the geyser, pool pump, aircon and fridge. My thinking is that evacuated tube solar geysers would be far more efficient at converting solar to hot water, compared to the conversion of solar to electricity to hot water, and installing one would reduce the required capacity for the solar panel array. Letting a solar geyser heat up the water to a higher temperature when there’s enough sun would also mean less hot water will be used (but also a risk if my kids open the tap on hot). Following that line of thinking and assuming my geyser would take 20kWh a day (600kWh /month), I could possibly spend R 30k for a solar geyser and use 200kWh a month or so for “additional heating” – thinking that’s worst case scenario. That would bring my monthly usage down from 1 100kWh to around 700kWh, and possibly reduce the battery size for the solar array. 11 x 455W worth of panels would yield around 826 kWh /month, with an 8kW inverter, 7kWh of storage and installation would be around R 190k. Same setup with 16 panels would yield around 1 201 kWh /month and power the electric geyser for R 217k, but for sufficient water in the mornings and evenings I’d likely need to add more batteries (which are expensive) Approximate costs from https://solar.co.za/product/solar-power-kit, I’m in Cape Town. My solar knowledge is very limited; what would your suggestions be to resolve this dilemma?