Abstract: A window frame insulation method for constructing a warm house of the present invention, provided in order to achieve the above objective, comprises: a placement preparation step (S10) for opening a portion of a wall body so as to insert a window frame before the wall body is formed, and forming a mold so as to form a stepped portion on the outer side of the wall body; a placement step (S20) for placing concrete so as to form the wall body within the mold; a preservation step (S30) for conservation of the concrete formed within the mold in order to prevent harmful effects; a window frame installment step (S40) for installing a window frame on the inner side of the opened wall body; an insulation material installment step (S50) for installing insulation material in the wall body except for the window frame; and a finishing material installment step (S60) for installing finishing material on the outer side of an outer insulation material.