Upgrading ventilation systems is a key way schools can reduce the spread of the coronavirus when campuses reopen, but some districts in California are finding the cost of those upgrades to be insurmountable. Some districts have recently been able to upgrade their HVAC systems using local bond money. Some hope that the Legislature will place a multi-billion bond on the 2022 state ballot to provide new money for school facilities. Others are hoping President-elect Joe Biden will push through infrastructure legislation that includes money for schools. But few funding streams are guaranteed, and they may not be sufficient to cover the regular inspections and stringent filter replacements that HVAC systems require.