Use It or Lose It

Managing classrooms for optimum efficiency.

Empty classrooms, small class sizes and decreased enrollment may lead community members to conclude that its school facilities are under-used. But how can schools address this concern?

Many factors can help determine efficient classroom use. One important factor relates to changes in education. As educators have learned more about effective teaching, classroom methods have changed. Special education and programs for the gifted have been initiated, and technology has been introduced to each classroom. In addition, class scheduling affects a school's ability to provide learning opportunities for students. All of these things affect room usage and building capacity.

Another factor to be considered in determining efficient room use is how a school calculates student capacity. A school may arrive at an inflated design capacity by multiplying a specific number of students in the classroom with the number of classrooms in the building. This method makes an assumption that all classrooms are occupied fully every hour. If this were true, the classrooms would have a 100 percent rate for room use, and that is an unrealistic student occupancy figure.

Schools must analyze classroom use and student occupancy to efficiently use buildings for staffing purposes and to project operational and maintenance costs; therefore, calculations should be based on a study of the master schedule to determine the number of periods per day. The traditional scheduling standard was based on allowing one period per day of each classroom to be used as a teacher-prep space and not as a classroom. This resulted in an 83 to 87 percent utilization factor of the room, depending on the number of periods per day. Changes in educational delivery methods have made this calculation even more complex.

Pinpointing variables

Scheduling modifications can affect room use. Block scheduling, for example, often leaves a room unoccupied for part of the day, which contributes to lower classroom utilization. Some planners have recommended a 75 percent utilization factor, while others have recommended an 85 percent utilization factor to determine the capacity for a school operating on block scheduling. To make classroom use more efficient, teacher offices sometimes are provided to allow classrooms to be scheduled at closer to 100 percent efficiency. Scheduling modifications should be flexible in order to accommodate student and teacher scheduling conflicts and curriculum enhancement.

The variable with the biggest impact on student capacity is class size. The number of students scheduled in each classroom can vary greatly depending on curriculum and program-delivery methods. Capacity is influenced further by the fact that enrollment fluctuates during the day and during the lifetime of a building. For example, a high school completed in 1997 for 3,000 students now has experienced an enrollment decrease, and classrooms stand empty for several periods per day. However, within five years, enrollment will rebound, and the school will utilize the classrooms again. Table 2 indicates lower room utilization because classrooms stand empty during several periods, but maintain a high occupancy average when used. When class size is taken into consideration, the analysis is based on student occupancy per classroom.

The high school in Table 1 varies the maximum class size from 16 to 33 students for the same classrooms throughout the day, depending on the subject being taught. For example, a home-economics classroom used for a child growth and development class has a maximum class size of 30. The same classroom used for an early-childhood class has a maximum class size of 16. A math classroom may have a 25-student maximum one period, while the next math class in that room may have 32 students. Occupancy rates vary for other reasons, such as students traveling off-site for specialized learning, work-training programs and alternative education. Table 2 shows an example of how these variables can affect classroom use.

Calculating usage

Curriculum course sections, the number of classrooms, and class size must be reviewed to determine the amount of use a building can endure while still providing a comfortable environment. A building's usage affects its capacity.

Two methods can be used to determine a school building's capacity. Reviewing the master schedule and tallying the number of students in each class section will identify class sizes, unoccupied periods, the number of classrooms, teacher prep practices, and classroom uses for purposes other than instruction, such as a study hall or advisory session. An accurate classroom utilization study will reflect the building's functional capacity.

The method of reviewing the number of students enrolled in a subject and then calculating the number of required classrooms according to desired class size is best used in a traditional schedule when one class period is unassigned for each classroom. This allows flexibility for scheduling conflicts and variations in class size using an 85 percent classroom occupancy rate.

In Educational Facilities, Basil Castaldi identifies a formula for determining the required number of teaching stations. His method also provides an allowance for scheduling conflicts and variations in class size:

Teaching Stations (T.S.) = 1.25 E/C × n/N

  • T.S. = Required number of teaching stations.
  • E = Number of students enrolled in a given course.
  • C = Desired class size.
  • n = Number of periods per week student attends a given class.
  • N = Number of periods in the school week.

Each of these methods provides flexibility to accommodate scheduling complexities, curriculum enhancements, flexible delivery methods and minor enrollment fluctuations.

An acceptable average of room utilization and student occupancy is 95 percent for select subjects if the building is operating at capacity. Achieving more than 90 percent average student occupancy for select subjects is possible whether or not the building is operating at capacity. Achieving a 75 to 90 percent average for room utilization and student occupancy by departments in core subjects seems reasonable.

Comparing high schools with enrollments of 900, 2,400 or 3,000 indicates variations in student occupancy. A broader spectrum of course offerings in any given subject may lower the average student occupancy per department per day, regardless of the total school enrollment. Each department's classroom usage will be different and will need to be analyzed. Substantial variations occur among districts in philosophy and curriculum usage, and this affects classroom use.

Just the facts


  • Operating below optimal capacity results in inefficient staff assignment and space usage, thereby creating excessive operating and maintenance costs.

  • Closing a building may be desirable if the district-wide classroom utilization rate is low.

  • Expanding learning opportunities often increases the need for classrooms and staff. Scheduling becomes complex, and the efficiency of a space's usage may decline. This, in turn, increases operational and maintenance costs.

  • Varying characteristics among districts alter classroom utilization and student-occupancy rates. For example, one district may have a high percentage of students with special needs that require specialized spaces. Another may have many students that go on to higher education, requiring expanded curriculum opportunities. Both will result in small class sizes and the need for more classrooms.

  • Scheduling spaces such as large-group lecture rooms, auditoriums, a black-box theater, or small-group rooms fluctuates throughout the year; those spaces are difficult to consider as assignable classrooms.

Table 1: Existing high school, 3,000-student capacity — 2,468 current enrollment

Subject Number of Classrooms Classroom Utilization (% average per day) Preferred Number of Students per Section Students per Section Occupancy per Classroom Average Occupancy per Classroom
English (Language arts) 19 56 15 to 32 6 to 32 35 to 99% 83%
Math 15 65 22 to 33 15 to 34 74 to 95% 89%
Science 15 63 5 to 31 2 to 32 44 to 97% 83%
Social studies 11 63 21 to 33 15 to 34 72 to 96% 90%
Health 2 88 31 to 33 24 to 33 95% 95%
Special education 5 51 5 to 30 1 to 23 49 to 77% 69%
Foreign language 9 65 25 to 32 9 to 31 74 to 97% 84%
Business 8 58 25 to 40 19 to 33 85 to 94% 89%
Art 5 53 20 to 30 11 to 27 47 to 100% 81%
Family/ consumer science 4 63 16 to 30 8 to 30 68 to 87% 68%
Vocational education 6 36 16 to 30 4 to 28 58 to 100% 82%
Driver education 1 88 27 25 to 27 93 to 100% 97%


Table 2: Existing high school 2,400 enrollment — 30 students per classroom policy for core subjects

Subject Number of Classrooms Student Occupancy per Classroom Student Occupancy per Classroom Average Students Per Section Average Section Size
Language arts 11 66% to 88% 78% 8 to 30 23.3
Math 10 55% to 80% 73% 11 to 28 21.4
Science 10 56% to 90% 78% 14 to 27 22.2
Social studies 9 79% to 92% 85% 18 to 30 25.9
Foreign language 6 48% to 73% 61% 11 to 26 18.8

Rydeen, FAIA, is an architect/facility planning specialist and former president of Armstrong, Torseth, Skold & Rydeen, Inc. (ATS&R), Minneapolis. Erickson, AIA, REFP, NCARB is president of Armstrong, Torseth, Skold & Rydeen, Inc. Hanauer, REFP, is an educational planner for the firm.

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