To change the default hourly rates for a space calendar, go to Kitchen Settings > Calendars > Pencil icon to edit (next to each calendar) > Default Hourly Rate.

Here, you can also change your off-peak time parameters and rates to incentivize booking during certain times. Once you have added your rate and time parameters for off-peak, click Save. These changes will only apply to the specific calendar you are editing. 

As a reminder, individual calendar hourly rates, including off-peak rates, will apply to hourly clients and clients on credit-based billing plans. To incentivize off-peak rates for time-based billing plans, you can set an off-peak overage rates when creating the time-based billing plan.