That means deciding what is inside and what is outside the conditioned space. Your conditioned space is everything inside the insulated walls
A thermal bridge is an area which has a higher heat or cold transfer than the surrounding materials resulting in an overall reduction efficiency control of the building.
Orient the building to take greatest advantage of seasonal sun angles for both passive heating and cooling and for maximum solar energy production.
U-Factor measures the rate of heat transfer and tells you how well the window insulates. U-factor values generally range from 0.25 to 1.25 and are measured in Btu/h·ft²·°F. The lower the U-factor, the better the window insulates.
Generally applied towards walls, ceiling, and floors and U-values for windows and doors. In cold climates, typical R-values are R-30 to R-40 for walls, R-60 for ceilings and R-48 for floors. In warm climates typical R-values are R-19 for walls, R-38 for ceilings, and R-19 for floors.