Until a few years ago, economy in public funded buildings during construction or retrofitting was focused on investment cost and not very much on the cost for maintenance and energy use. Lately there has been a change in the rules and laws from the Ministry of Housing, resulting in the possibility of using total-economy. Total-economy incorporates all present and future investments (e.g. operational and maintenance costs) into one number making it possible to invest more money when constructing a building and save the money later on due to lower cost for maintenance and energy consumption.This paper will give a summary of the two methods which are currently used in Denmark. The pros and cons of each of the methods will be discussed and key parameters for the calculations will be estimated.