THIS CASE STUDY WAS MADE TO DETERMINE THE EFFECTS OF NONFENESTRATED CLASSROOMS ON CHILDREN'S LEARNING ACHIEVEMENT. USING GRADES K-3, OBSERVATIONS WERE MADE IN TWO SCHOOLS OF SIMILAR CONSTRUCTION AND DEMOGRAPHY. THE STUDY WAS MADE IN THREE SETTINGS--A YEAR IN EXISTING FENESTRATED CLASSROOMS, A YEAR WITH ALL WINDOWS REMOVED IN THE TEST SCHOOL AND ONE-HALF YEAR WITH THE WINDOWS RESTORED IN THE CONTROL SCHOOL. DATA DERIVED FROM RECORDS ON LEARNING ACHIEVEMENT AND CHILD BEHAVIOR DURING THE STUDY SHOW A CLOSE PARALLEL IN PUPIL LEARNING ACHIEVEMENTS BETWEEN THE TWO SCHOOLS AND THAT WINDOWS HAVE LITTLE EFFECT ON THE CHILD'S ABILITY TO LEARN AS REFLECTED BY HIS LEARNING ACHIEVEMENTS. DATA WERE ALSO KEPT ON ABENTEEISM. A QUESTIONNAIRE TO SAMPLE THE REACTIONS OF CHILDREN AND TEACHERS SHOWED GENERAL APPROVAL OF WINDOWLESS CLASSROOMS BY TEACHERS STATING THAT THE ROOMS HAD FEWER DISTRACTIONS FROM OUTSIDE NOISES AND WEATHER CHANGES, A FEW TEACHERS COMPLAINED ABOUT STUFFINESS AND DRAFTINESS IN THE ROOMS. PARENTS' REACTIONS WERE REPORTED BY TEACHERS, MINOR RESISTANCE TO THE STUDY WAS ENCOUNTERED, THE CROSS SECTION OF PARENT ATTITUDE RAN FROM CURIOSITY TO INDIFFERENCE. THE CHILDREN SURVEYED SHOWED COMPARABLE ATTITUDES. ADEQUATE ARTIFICAL LIGHTING AND MECHANICAL VENTILATING SYSTEMS WHICH CONDITION THE AIR TO DESIRED WARMTH AND FRESHNESS ARE ARCHITECTURAL REQUISITES. IN BUILDING PLANNING FENESTRATED CLASSROOMS SHOULD BE CONSIDERED ONLY WHEN EDUCATIONAL PURPOSES ARE SERVED AN OUTSIDE VIEW. (GM)