The water heater was purchased for 169€ on 1/9/2021. After a while, it started making noise. A technician came and changed the pressure relief valve, but after two days, the same issue occurred again. On 21/4/2023, the heating element needed to be replaced as it was filled with salts, just like the water heater itself. This cost an additional 77€ (the anodes were also corroded), while the service for changing the anodes was supposed to be included in the warranty. I should note that I live in the center of Athens, and such a situation cannot be justified by water hardness and salts, as the water quality is fine. In the past few days, it started leaking water. There is a hole next to the thermostat from which water is flowing out. Let's see how much they will charge this time. Judging by the total cost, including the service and spare parts from an authorized service center to avoid voiding the warranty, the purchase is not worth it, as in less than two years, I have called the service twice and the repair cost is close to half the cost of the water heater.

Purchased in December 2016 for €130.00 and it works perfectly to this day and is in excellent condition, at least externally. I have only changed the thermostat once, cost about €10.00 from the internet and I installed it very easily myself. I decided not to do any anode maintenance to see how long it would last. From my experience so far and the knowledge I have, I will mention some important details about water heaters because a lot is written...
1. At the entrance of the house's water supply network, a pressure reducer with a cut-off at 4 atmospheres is needed. The network pressure causes huge damage to the whole house in the medium to long term!
2. Put an expansion vessel at the cold water inlet of the water heater to avoid the "leaks," as many write, from the relief valve. These are not leaks, it is the normal operation of a closed vessel where water is heated to 80 degrees Celsius. It needs space to expand and does so through the valve. COMPLETELY NORMAL! When you cook with a pressure cooker, doesn't the valve open at some point due to pressure and steam is released? It's the same situation. Alternatively, instead of an expansion vessel, permanently connect a silicone hose to the outlet of the relief valve and direct the water into a drain. That's what I've done too.
3. The temperature of the cold water inlet is very important. It's one thing in the summer with an inlet temperature of 25 degrees to raise it to 60 degrees, and another in the winter with an inlet temperature of 5 degrees to raise it to 60 degrees. Huge difference in energy and heating time.
4. Do not set the thermostat above 60 degrees Celsius, it is a crime for the machine and the electricity meter. Above 60 degrees, scale forms rapidly, the well-known sediment, the anode is depleted faster, high pressures are exerted inside the tank that destroy everything, the relief valve operates continuously, unnecessary energy is consumed. Overall, it's a disaster for the machine. Technicians set it directly to 80 degrees... so they have work in the future. How else will they make a living.
5. Prefer horizontal water heaters. The vertical ones are prone to failures, for various reasons.
6. Always remember that as soon as you open the hot water to use it, at the same time the water heater replenishes the same amount with cold water! So, if you heat 80 liters to 60 degrees for someone to take a bath using 30 liters, then 30 liters of cold water enter the tank, which in winter will be between 5-10 degrees, resulting in a significant drop in temperature throughout the tank! Therefore, use it smartly. Do not fully heat the tank to use small amounts at long intervals, because you are simply wasting hot water.
After every use of more than 10 liters, turn on the device for 5-10 minutes and you will always have hot water in less time, thus with less consumption. This is the tactic I follow and my 80-liter water heater covers 5 people!!!
I hope I helped.

UPDATE: 3/2/2025
In December 2024, it completed 8 years of operation! It works perfectly normally without any visible wear, always following the conditions I mention above.
The only thing I've noticed for about two months now is the intense "boiling" sound during water heating, which means the heating element has scaled up. So in the spring it needs to be drained, cleaned internally with a pressure washer, and the heating element, anode, and gasket replaced.
I will update again.

UPDATE: 3/11/2025
I contacted the company's authorized service center and ordered the maintenance kit for this particular model and a new heating element. I received them at home in 3 days. The maintenance kit contains 2 anodes, 1 gasket, and 1 relief valve. Total cost, €50.00.
I took the water heater down from the wall and, as I suspected, the heating element was completely covered with limescale about one centimeter thick, the two anodes were completely worn out, and the tank was about 1/3 full of a layer of limescale! All this while using the water heater under the conditions I mentioned above… imagine turning it on at 80-90 degrees… DISASTER, as I also explained above.
The tank was washed inside with water and all the limescale was removed. I installed the spare parts after it was secured back in place on the wall and now it is like new, silent, heats up faster, and I have the whole tank available with water again.
It will easily work for another 8 years and we'll see…

The water heater arrived broken. The technicians who delivered it called in front of us to use the warranty immediately after installation.

ELCO sent a technician who changed the thermostat and it worked.

Although it is 80 liters, the water is not enough to comfortably take a bath as with the 60-liter one it replaced. It only provides a quick shower for two people. Sometimes it's only enough for one person. Additionally, it never turns off. It reaches the temperature we have set and stops, but after 30 seconds or within 2 minutes, it turns on again, works for half a minute to a minute, turns off again, and repeats. It does this forever until we turn it off from the panel. Obviously, it doesn't accurately understand how hot the water is. I imagine something is overheating and giving the thermostat a wrong indication.

After a few months, it stopped working again. Their technician came again and changed the thermostat. The behavior with the on-off cycle was the same.

And after a few months, it stopped working again, for the third time. Their technician came again, changed the thermostat again, and the same on-off cycle continued.

Every time we mentioned the issue, that it doesn't turn off, but the technicians ignored us while on the phone and closed it, saying that a technician will come. The last one said that if it happens again, we should call them to come and clean the salts, admitting that it won't solve the problem since it has been happening from the beginning, before the water was even filled for the first time. This means that we will waste 80 liters of water just for fun, for a water heater that arrived DOA and they refuse to replace. Plus, the days we have to live with cold water because they don't have a technician to send, and we have to wait, and we also have a baby...

Unacceptable situation. Thank you, but I will not support a company at my expense just because it is Greek. Personally, I will choose a reputable foreign one. Also, if the problem is not resolved before the warranty expires, the matter will go to the consumer advocate