Hudiksvall Municipality will build a new preschool. The goal is that the pre-school should reflect the municipality's environmental goals and meet building regulations. The wall structures that are compared in the report is an insulated wooden frame and a frame of lightweight concrete blocks from H + HWall structures are compared within the areas of U-values, air tightness, thermal storage capacity, fire ratings, moisture, durability, emissions and environment. In these categories the two wall structures will be rated in a scale from 1 to 5 and then the categories are weighted against each other. The weighting is based on Hudiksvall Municipality's assessment of the categories importanse for their final selection.The results of the comparison show that the concrete structure is recommended for the construction of pre-school with 27.55 points against the wooden structures 23.70 points. The highest possible score after weighting is 34 points.