Bounce houses can be inflated either indoors or outdoors. However, if you're setting it up outdoors, it will need to be properly secured. Most bounce houses come with stakes. If you set yours up on the lawn, use the stakes to secure the bounce house to prevent it from blowing around (or even away) in strong wind. You could also set up a bounce house on hard ground, but you'd need to use sandbags as weights, and that process gets more complicated. If possible, we recommend setting up your bounce house on grass.