The maximum power that a relay can switch relates to the temperature rise in relation to reasonable contact life. An over-power condition dramatically shortens relay life. Signal handling relays have their power rating specified in either volt-amps (VA) or watts.
Relays that have their power rating given in watts are DC relays. If the relay is a DC type, the relay's power must be used to rate the relay's power handling capability.
AC type relays are designed to handle AC loads and are usually rated in volt-amps. When power is rated in VA, the power factor is not a consideration and volts switched times amperes switched or carried is the calculation used.