A global survey of adverse energetic effects of increased wall insulation in office buildings: degree day and climate zone indicators

The energy efficiency of a building depends to a large measure on the characteristics of its envelope insulation. In the special case of internal gain dominated buildings, excessive building insulation may prevent the heat loss through the walls (anti-insulation effect), and thus generate the need for energy-intensive active systems to remove this thermal load. Detailed energetic simulations of a typical office building in Malaga (Spain), Dubai (UAE), and El Dorado (USA) show this anti-insulation effect and its dependency on climatic, constructive, and use factors. Results indicate that buildings in a predominantly cooling environment but within a certain range of heating degree days (HDD) will display this behavior: with very few to no HDD, the building’s energy consumption becomes insensitive to insulation increase (Dubai case); with a low number of HDDs the building becomes sensitive to anti-insulation (Malaga), and once a threshold is passed (El Dorado), the building’s energy consumption decreases with increased insulation. In order to further explore these limitations, simulations in 132 global locations of the building response to a step change in insulation are carried out. Results indicate that buildings in the Köppen climate zones Csa and Csb (Mediterranean climate), in locations with less than 2000 HDD and between 2000 and 5000 cooling degree days (CDD) are most susceptible to this anti-insulation behavior; however, quantitatively, the efficiency loss in these areas due to the insulation increase does not exceed 1 % of the overall energy consumption for the particular building studied and thus remains of limited importance.