Exactly, I know svchost.exe belongs to Windows, that why I asked.
Don't forget multiple Windows Services will use the same process, check the PID from Task Manager. I calculated a difference of 1,000K of RAM (Private Working Set) between disabling and enabling the WF service, but usage is not noticeable at all.
Windows Firewall is an integrated part of Windows, any RAM or CPU usage would be considered negligible. IMO.