Background The household appliance sector accounted for around 28% of EU electricity consumption in 2007. In the European economic area, household electricity consumption is some 4 100 kilowatt hours (KWh) per year, of which 100-200 KWh is consumed by electric ovens. Electric ovens are among the least energy-efficient household appliances, with an efficiency of about 10-12% relative to the input power. Some 11.5 million electric ovens are sold each year in the EU (2008 figures). Production of ovens is also marked by high energy consumption, in particular because of the enamelling process for oven interiors. Moreover, the enamels often contain toxic substances, such as nickel and cobalt. A reduction in energy consumption in both the production and use of electric ovens would result in significant energy savings in the EU. Objectives The long-term objective of the HEO project was to address the issues of energy-efficiency, over-dependence on fossil fuels, greenhouse-gas emissions, the use of toxic chemicals, and the overall production of waste in the manufacture of domestic ovens. The project's specific aims were to demonstrate the feasibility of an innovative enamelling technology for electric ovens, in order to achieve up to 50% energy saving in the production process; to demonstrate an innovative oven design to reduce energy consumption by some 30% relative to existing state-of-the-art electric ovens; and to avoid completely the use of nickel and cobalt in oven enamels. Results The HEO project demonstrated that its innovative Highly Efficient Ovens (HEO) can reduce oven energy consumption and enable cost savings in comparison to conventional ovens. The project increased energy efficiency during the use stage by about 30%, compared to conventional ovens; and by more than 60% during the manufacturing stage, because of the lower temperatures required for curing the new coating compared to the conventional enamelling process it replaces. The new enamelling material comprises an exclusive sol-gel inorganic compound, which is applied in transparent nanometric layers. A number of environmental benefits result from the project’s approach. The new production process enables the elimination of toxic substances, such as nickel or cobalt, which are contained in traditional enamels. HEOs have a lower global warming potential (GWP), in the range of 576-738 kg CO2 eq. instead of 812-1 478 kg CO2 eq. for conventional ovens, when considering over a lifetime of 19 years. Therefore, HEO project ovens have a potential to save between 9% and 61% of the GWP, depending on the assumptions for the cleaning options. The project also demonstrated that replacing conventional domestic electric ovens by highly-efficient models at the EU28 level would lead to significant environmental savings in the range of 0.5-5.2 Mt CO2. The HEO oven prototype was given an A++ classification in the EC labelling scheme that entered into force in January 2015, based on a standard energy-efficiency index. This is mainly due to the stainless steel (inox steel) oven cavity lining with increased reflectivity, which improves the efficiency of the heating elements resulting in less electric power being consumed during cooking. The success of the project was quantified by a Life Cycle Assessment (LCA), which showed that the HEO project’s ovens reduced energy consumption and allowed cost savings in comparison to conventional ovens. The achievement of the project’s goals was shown to be technically and financially feasible, and could help companies operating in this sector to reach targets set by the Energy Efficiency Framework Directive (Directive 2012/27/EU). The project is also relevant to the updating of the Industrial emissions requirements foreseen by Directive 2010/75 and/or BAT reference documents, and of the label scheme for oven energy efficiency classification. The project partners indicated that their demonstration system could be easily exploitable on a large scale. Replication is possible because the process requires few modifications to existing manufacturing plants, simplifying knowledge transfer. The new oven can be used all over Europe, since there are no geographical or regulatory limitations on this product. The project team undertook extensive dissemination and networking activities to promote the new technology. The life cycle costs of the HEO project’s oven prototypes are lower than for a conventional oven, in the range of €194-247 per oven over its lifetime compared to €320-479 for a conventional oven. The consumer could save 41-61% over the lifetime of the oven, depending on the cleaning option assumed for the conventional oven. Even for the worst HEO prototype scenario, 25-50% of the lifetime costs would still be saved by the consumer. At the EU28 level, the results suggest that replacing conventional domestic electric ovens with HEO ovens would lead to significant cost savings, in the range of €0.5-1.96 billion/year. Most of the latter would be direct consumer savings, because of lower energy consumption and lower energy bills. Assuming an uptake rate of 5% per annum, it would take 20 years to achieve these benefits. At 10% annual uptake per year, these savings would be obtained in half the time. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).