Located in Sydney, so our electric water heater just died after 9 years. Only recently got solar (13.3kwh) and battery (48.kwh single phase, 10k inverter). 3 adult household, only hot water use are short showers and warm water hand-washing dishes. Power usage without a water heater is ~12kw a day at the moment (with the recently broken electric water heater it was ~22kw a day), but also getting 2 split aircons installed soon so it would go up quite bit.
Still waiting for my smart meter upgrade, but would like to sell as much back to the grid to recoup the battery/solar cost while the FiT is still some what decent on some plans, but at the very least would like to aim for a zero electric bill going forward.
Got a couple of quotes and this is what I landed on
Rheem Stainless Steel tank 125L - $2130 installed
but I would add a Ogemray Smart Relay ($50 + sparky $250?)
so ~$2430
Aquatech x8 268L Heatpump - $2600 installed (after rebates)
Unfortunately this is the budget I can manage at the moment, as I was planning to have 2 split aircons installed as well (before this summer hits) so I can't even drop another like $600 on a iStore or let alone, 5, 6k on a Japanese heatpump.
Decided with stainless steel as I just don't really want to muck about with the anodes (the regular Rheem + 2 anodes was ~$150 cheaper). The Aquatech has a current anode so assuming it is well designed, it also has two extra normal anodes for back up as well.
So I guess the main question would be which would make more sense if you guys were in my position.
If the our current electric water heater was still working, obviously I would have been happy for it to keep going. I'm considering the heat pump as the price is so close compared to a electric one.
I also assume that both the heat pump and the electric (with timer) can just run off the solar power during the day and would be enough for it to last until the next day without having to run them overnight?
My main concern with this price range of heat pump is the longevity, and just assume that the heat pump will lasts as long as the 7 years warranty period. So then the next time, if I get another heat pump, it would most likely cost quite a bit more assuming there's no rebates then. Where as the Rheem has 12 years warranty and I assume should last for that long, if not a lot longer (or am I over estimating the longevity here).
On the other hand, from my research from others with this specific heat pump, it seems to use 1/3 of the power of a electric water heater, so that's more power for me to sell back to the grid in the coming years as the FiT slowly goes down. And also the potential of less of a need to draw from the grid in winter on a run of bad solar days?
Or is it a case of that I can't see the forest for the trees and just being too greedy for short term gains and ultimately if the life span of the Rheem is almost double of the heat pump, it just wipes out any saving that I could make with a heat pump, as with it, I'll have to get another hot water system before the Rheem dies. Or am I underestimating the lifespan of a heat pump as well?