Just buy it least 1 year. I think It is not good enough. Always stop work and no hot water. I need restart it every day. If not, I will no hot water to use on second day.

Installed in 2008, replacing old electric storage unit. We have a family of 5 and ran it on a timer from 9am to use the heat of the day and it will only run for around 2 hours max in the coldest party of winter. Always had plenty of hot water. Cost around 50c a day to run as it will only need an hour to reheat in summer.
We have since moved to a new house in (2016) with gas h/w and I’m just about to get another Stiebel electron to replace it to save on the $1200 a year gas bill.
In short it has been a great investment and I highly recommend this unit.

Had the WWK302 for a few months now, very happy with unit. I was actually quite surprised how quiet it is, I'd say about the same as a pedestal/desk fan on low/med speed. Power consumption is about 600w & normally runs for about 4-8 hours per day. I do have two issues with it, one being the size but being 302L not much can be done about that (issue is more I did not provision for such a big HWS when building). The other issue is there is no timer/controller, so you will need a external timer to take advantage of solar production or off-peak tariffs.

When planning to build our brand new home, we researched the for best Hot Water solution and ordered a new Stiebel Eltron Heat Pump. We wanted a reliable and efficient hot water supply. We received great service and advice and our new heat pump was delivered on time so it could be installed when the builders required it. We have now been in our new home for about 2 weeks and are very happy with our decision. The Stiebel Eltron Heat Pump is super quiet and delivers plenty of hot water.

We needed to urgently replace our hot water system with an energy efficient electric system. We have solar panels and after much research came to the conclusion that a heat pump was the most cost and energy effective solution for our set-up. Dan at Stiebel Eltron was very helpful. We purchased the heat pump through retravision commercial Osborne Park who gave a great price (much cheaper than competitors). We always have hot water, it's quite quiet (located behind our laundry) and our electricity cost has come right down to not much at all. So far so good!

We needed to replace our faulty solar pannels and the pump in the tank.The solar has been nothing but trouble so acter doing some research and getting a recommendation from a friend we decided to go with the Stiebel Eltron WWK302 system.

The install was done with minimum interruption for us and so far it's been great, hot water when we need it.

Worth mentioning that on some reviews that I read people were concerned about noise from the pump, yes you can hear it but it's a quiet hum that hasn't bothered us at all.

I've recently installed 6x Stiebel Eltron WWk-302 units at various locations.
Compared to the new units they are so much quieter, and no complaints from the clients.
We have also complete a few solar hook ups, great option!!!!! Simply and easily done, great selling point for some for clients who have are going to install solar panels.