Nowadays, the increasing of global climate change and warming is leading governments, consumers, and firms towards a low-carbon economy. A lot of research shows that about 75% of the environmental impacts related to energy-related products is due to the use phase. Therefore, energy-related products, such as household appliances, are responsible for the consumption and depletion of natural resources. The eco-design of household appliances is a necessary approach to analyze and reduce the environmental impacts related to these products, considering materials, efficiency, and energy consumptions. In Europe, as well in China and America, the eco-design is becoming an Integrated Product Policy to support the Energy Labelling of several energy-related and consuming products. This paper deals with a design methodology to support the eco-design of cooking ovens by the simulation of the product performance. Two simulation cases have been analyzed: the energy consumption, which is provided by EU regulations No 66/2014 and No 65/2014 and the baking test. Even if regulations only provide the energy consumption test, the baking test is necessary to analyze the functional quality of the product. Therefore, two levels of simulations are necessary to complete the eco-design approach of cooking ovens. The results show that the proposed methodological approach can reduce the time-to-market and enhance the design optimization from the early design phases.