Planning a construction project, the investor frequently faces the choice of the option of the planned investment. Assessment of options is difficult due to the complex nature of construction projects. Various methods of multicriteria evaluation are successfully applied in the assessment and analysis of options. For those methods to work, a handful of information must be prepared beforehand. Among others, it is necessary to establish the assessment criteria and determine their weight for specific cases. This stage is implemented in cooperation with experts. The results of evaluations, obtained on the basis of the experts' opinions, must be processed and prepared. The paper will discuss one possible option for assessing the experts' opinion.

The influence that general contractors and subcontractors have on the operation of a company is immense. Keeping this in mind, the authors have decided to develop and algorithm based on the analysis of partnering relations between construction companies that would select the best possible construction company for the purposes of cooperation. This algorithm, developed for a given construction company, is meant to support its decision-making system in the field of the selection of another construction company to cooperate with. The author has made references to earlier research, in which she had used the ELECTRE III method, and in which she bad analysed the possibility of applying the BIPOLAR method in order to solve the problem of the selection of a construction company to develop partnering relations with. The author provided an example of the calculations performed for a selection of construction companies.

The article raised issues related to the design and execution of low-energy objects in Polish conditions. Based on the designed single-family house, adapted to the requirements of the National Fund for Environmental Protection and Water Management ("NF40" standard), the tools to assist investment decisions by investors were shown. An economic analysis and a multi-criteria analysis were performed using AHP method which had provided an answer to the question whether it is worthwhile to bear higher investment costs in order to adjust to the standards of energy-efficient buildings that fulfil a minimal energy consumption's requirements contained in Polish law. In addition, the variant of object that had optimal characteristics due to the different preferences of investors was indicated. This paper includes analysis and observations on the attempts to unify that part of the building sector, which so far is considered to be personalized, and objects in accordance with the corresponding idea are designed as "custom-made".