The purpose of this paper is to get an understanding if the climate declaration is an effective policy instrument in the construction sectors supply chain. In present time, it is difficult to predict how the effect of this instrument will affect the market and if it will be an effective and prerequisite regulation in the future. A policy instrument can contribute to higher costs for both organisations and individuals. Therefore, the aim of this paper is to examine whether the transaction costs differ before and after the climate declaration was introduced, dependent on the public or private construction sector and investigate if there is a difference dependant on the design-build contract or design-bid-build contract as a procurement form. With the help of a survey that was distributed to over 590 individuals in 38 different companies, the survey asked questions regarding their experience in the design phase, procurement phase and the construction phase of, request for tenders and tenders, before and after the climate declaration was introduced. The results demonstrate there is a difference before and afterwhich can indicate that the transaction costs also have increased regardless of which sector or form of procurement.