{"id":11290,"date":"2025-03-22T08:08:08","date_gmt":"2025-03-22T08:08:08","guid":{"rendered":"https:\/\/mjarc.com\/certificacao-energetica-casas-antigas\/"},"modified":"2025-03-22T16:46:19","modified_gmt":"2025-03-22T16:46:19","slug":"energy-certification-for-old-houses","status":"publish","type":"post","link":"https:\/\/mjarc.com\/en\/energy-certification-for-old-houses\/","title":{"rendered":"Energy certification for old houses"},"content":{"rendered":"

What is energy certification?<\/h3>\n

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Energy certification<\/a> is a document that assesses the energy performance of a building, giving it an efficiency rating on a scale from A+ (most efficient) to F (least efficient). This process analyses various factors, such as thermal insulation<\/a>, heating, ventilation and air conditioning systems, type of windows and building materials.<\/span><\/p>\n

In Portugal, energy certification is compulsory for new and existing buildings when they are put up for sale or rent. The main aim is to promote energy efficiency and inform consumers about the energy costs associated with each property as well as the improvement measures they can implement and the respective benefits in terms of energy consumption.<\/span><\/p>\n

 <\/p>\n

Is the energy certificate compulsory for old houses?<\/h3>\n

Portuguese legislation on energy certification of old buildings is defined by Decree-Law no. 118\/2013 of 20 August<\/a>. This law states that all houses, regardless of how old they are, need an energy certificate if they are placed on the market for sale or rent.<\/p>\n

The certificate must be presented before the purchase, sale or rental contract is signed, guaranteeing transparency about the property’s energy performance. In addition, whenever a building undergoes interventions of more than 25 % of its value, it will be compulsory to obtain a new energy certificate.<\/a><\/p>\n

\nChallenges in energy certification of older homes<\/h4>\n

Older homes, especially those built before the implementation of energy efficiency standards, can have a lower energy performance due to factors such as:<\/p>\n