Makes an energy-eater of his work very well

I've been using this immersion heater to our paddling pool in the garden (about 12 degrees every day with well water filled) heat (2 mx 1.5 m, ie about 1,000 liters). After four hours, the water is about 30 degrees.
I run the boilers only when the sun shines and free passes over the photovoltaic system, otherwise the fun costs about 40 cents per hour.
Top equipment, great performance, absolute recommendation!