The following shall be exempt from sections 81-1608 to 81-1626 :

(1) Any building which has a peak design rate of energy usage for all purposes of less than one watt, or three and four-tenths British Thermal Units per hour, per square foot of floor area;

(2) Any building which is neither heated nor cooled;

(3) Any building or portion thereof which is owned by the United States of America;

(4) Any manufactured home as defined by section 71-4603 ;

(5) Any modular housing unit as defined by subdivision (1) of section 71-1557 ; and

(6) Any building or structure (a) that is listed on the state or National Register of Historic Places, (b) that is designated as a historic property under local or state designation law or survey, (c) that is certified as a contributing resource with a National Register-listed or locally designated historic district, or (d) with an opinion or certification that the property is eligible to be listed on the state or National Register of Historic Places either individually or as a contributing building to a historic district by the State Historic Preservation Officer or the Keeper of the National Register of Historic Places.