It is of high quality in construction and appearance. It has an impressively accurate thermostat. It is very effective in a medium-sized room with good insulation. With the medium setting and without the fan, it raises the temperature by 2-3 degrees in less than half an hour in a room of about 12 square meters. It is excellent at maintaining the selected temperature afterwards, with the low setting and turning off when it reaches it. The timer has a half-hour range, simple and user-friendly.

On the negative side, when it turns on, it makes a noticeable sound/tick. It is common, but not as imperceptible as in another one I have (Mill SG2000LED). Its fan is also noisy. Personally, I do not use it though by choice.

Comparing it to the Mill SG2000LED, which has the same nominal wattage, the Delonghi HCX9120E is noticeably more efficient. It has twice the size, which may play a role in its performance. It appears capable of effectively heating larger spaces with insulation (~25-30 square meters). The Mill is quiet, though. This one makes that sound when it turns on, which may bother someone sensitive to sleep (not me). The fan of the Mill is almost silent, while the Delonghi's fan is not at all suitable for sleep.

I will write a long and detailed comment-review after explaining why I bought it. So, what I was looking for was a device mainly for the night, to avoid other solutions for this purpose that are more expensive. The space has poor insulation to bad insulation, with dimensions of 4x3.50. I wanted something that is not heating, but breaks the cold at night if something else is not working. I chose it because of the digital display, which is quite reliable (used for 3 months now) with the ability to adjust the time. That means you can set the time it will work, for example, 3 hours and then turn off by itself. This is very important for this job. It also has an automatic program that can lower the temperature gradually, thus reducing unnecessary consumption. This is not useful for me due to limited space, it's difficult to move it around, so I don't expect to use this feature. However, it might work for others. It performs well for this job. If it had a price between 70-85 euros, it would be the top choice. For those who need heavier use, they might consider the AEG or the French one, which have several reviews. I don't have an opinion to compare.

In terms of consumption, in full operation like all 2000 watt devices, it consumes 2 kilowatts. So, if we say it works for 10 hours a day, it would cost somewhere between 55-65 euros per month, depending on the electricity bill. This amount is approximately 60 liters of oil with a burner consumption of 3-4 liters per hour. Let's assume the optimistic scenario that it can do the same job as the pump in 1 hour of operation. We will see that the oil will last for 12-15, maybe 20 days, which is difficult to achieve. So, with the same amount of money, we have 10 more days of heating that we want. (Not to mention that radiators work according to the room where the thermostat is located). Now, let me talk about the device and a few things. Yes, the fan makes a certain noise. It doesn't bother me, I don't consider it noisy, definitely less than a fan heater. Although it is probably unnecessary and does more harm than good. Also, high fan usage and high temperature on the thermostat send the device into safe mode. With this combination, one of the "boards" that is not solid (on the back) expands to the point of touching the casing. The part that can be removed for access inside the device. The result is a technical short circuit. It stops, all the indicators on the display light up, and there is an audible signal. After this, the plug needs to be disconnected, left for a while, and then connected back to the socket. This is probably a protection against overheating, maybe because it draws more current than the nominal current with the fan and full resistance. So, the ideal setting is ECO-3 levels without the fan and a temperature of 20-23 degrees. With this setting, it will lower the levels if it remains on all night. This has been observed by many people, but with some reservations. If someone has a socket meter (maybe I will get one eventually), they will confirm if this happens 100% because of it. However, this happens and goes into safe mode. For those who want this kind of use, it is ideal, maybe better than the two more well-known ones. For heavier use, I think it's difficult. It also needs a good base and secure fastening. Easy to transport. It also has handle covers. The temperature is higher on the back side of the casing. I think the cable length is 2 meters. If someone doesn't want a digital display and timers, etc. Let him save the 20-30 euros to buy an analog ... also the design is excellent, it beautifies the space and not the opposite ... I hope I helped enough to potential owners ...

UPDATE ..5 YEARS .....
I won't change anything ..after 5 years it still exists and works properly ..so you can call it reliable .....beyond that, it's not efficient and economical as I have already mentioned, like any other appliance with high electricity prices nowadays ....how can it be useful and efficient ....based on experience ....
It is for mild days, don't expect it to stop, it's impossible .....
It works great on the 2nd level ..it's sufficient ..and it operates economically ..never with a fan ...if the days are not very cold ..after 1 hour, lower it to the 1st level ..and let it maintain ....

It is a better solution than cheap and plastic air heaters which will burn out in 1-2 years and create a suffocating atmosphere .......

Set it to 22-24 degrees, 2nd level and after a while, switch to the 1st level .....it can maintain a room in not very cold conditions ...depending on the area and insulation ....it is the most economical use that can be done .....