The average response time to a rental request on Hygglo is 15 minutes, but of course it varies from person to person and sometimes even per occasion. Someone being away on holiday for example can be slower to respond than usual.
On every ad you can find information about the person renting out, for example how fast they usually respond to a request. If you can't see the stats, this would mean they haven't had many rentals yet.
In the search results you can also sometimes see a lightning bolt. That means this person is usually really fast at responding.