Fairfax County’s Board of Supervisors on Tuesday adopted a $4.4 billion budget that keeps the residential property tax rate at $1.15 per $100 of assessed value while adding funds for affordable housing and environmental programs.

The budget, approved unanimously, allocates $2.1 billion to county schools and gives the county’s 13,000 employees cost-of-living increases of 2.1 percent, at a total cost of $14.9 million.

Last week, the board agreed to steer another $5 million toward affordable housing — for a total of $15 million — after the county realized it will have extra money next year through higher-than-expected commercial property tax revenue and cost-cutting measures that led to savings.

The board also agreed to create two staff positions for a new Office of Environmental and Energy Coordination that is meant to combat the negative effects of climate change.

A proposal to allocate $200,000 toward a legal-defense fund for immigrants facing deportation also won approval Tuesday.