4.1 A smart fridge could monitor your energy use and give advice when to maintain the product.
4.2 Monitoring could also be done with an old fashioned fridge thermometer. And by only adding wheels under the refrigerator, maintenance can be made easier. The coils at the back should be cleaned every three months to prevent dust from clogging the system, which can increase energy use op to 30%.
4.3 Standard Interface of product:
Opening the door and seeing the light on the inside. The color of this light could indicate the temperature. If the door is opened long the color will change towards red.