Charles Drew Elementary School

Background

The San Francisco Unified School District passed the Carbon Neutral Schools Resolution in 2017, which committed to reducing the greenhouse gas emissions by 2040 and increasing the energy efficiency of all existing district schools. Funded through a Proposition A Modernization Bond, Charles Drew Elementary School is the first school to be renovated, including upgrades to the lighting, boilers, and building envelope. The project began in April 2019 and is expected to complete in July 2020, resulting in a 63 percent energy savings and 34 percent cost savings annually, totaling $14,700 each year.

Charles Drew Elementary School is located in the Bayview District and serves over 200 children in Pre-K through 5th grade. In addition to its greenhouse gas reduction goal, the district plans to reduce the use of natural gas to heat district buildings 50 percent by 2030 in conjunction with the installation of solar panels.

Solutions

The district hired consultants to prepare a Zero Net Energy (ZNE) report to assess the feasibility of reducing the energy use intensity of the building below 20 kBtu/sq. ft. annually. The report highlighted the significant, cost-effective energy savings opportunities of switching to LED lighting and replacing the natural gas-fired boilers with an electric variable refrigerant flow (VRF) system.

The district has incorporated both measures into the modernization of the site, along with a newly insulated R30 roof.^* At the completion of the project, gas service will be terminated, and the school will be powered exclusively by 100 percent renewable hydroelectric energy from the Hetch Hetchy water system located in Yosemite National Park.

The savings measures and associated costs and savings are captured below:

Savings Measure	Cost	Savings Achieved	Notes
LED lighting	$1,065,000	42,450 kWh/yr.	Does not include 9 percent increase in heating due to lower heat output of LEDs
VRF system	$1,420,000	10,718 therms/yr.	Does not include 6 percent increase in electric usage on site
Insulated roof	$575,000	4,442 therms/yr.	R30 insulation installed

^*The R-value is a measure of thermal resistance, or the ability to prevent the transfer of heat by adding insulation layers to reduce energy consumption and associated costs. R-values are recommended based on the climate, heating and cooling system, and area of the building to be insulated. The higher the R-value, the greater the insulating power.

Other Benefits

Charles Drew staff previously complained that classrooms were too hot during the warmer months and too cold during the winter. In addition, light quality at the school was poor. The school eliminated these concerns by providing each classroom with individually controlled space conditioning and lighting upgrades. These controls will allow classrooms to become more comfortable for occupants and help reduce the amount of energy needed to heat and cool the spaces. Another additional benefit is that utility expenditures at the site are expected to decrease significantly and the possibility of adding solar to offset building load could drive these savings even higher. In the future, the district is looking towards ZNE-ready construction, an emissions-free fleet, and a shift to renewable energy.

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