Some bouncy houses require two fans to stay inflated and have two or more entrances. Some bouncy houses have multiple entrances, but can be inflated with a single fan. Just tie down any entryways that you don't need. Blast Zone inflatables are made of a breathable fabric that allows some air to escape through the corners, seams, and small holes in the material.
Since the inflatable is not airtight, you'll need to keep the fan running continuously to keep it inflated. This is typical for most inflatable gorillas and water slides in the constant air category, which are high-quality and durable inflatables. This 1200 watt (1.5 HP) inflatable inflatable house fan (link to Amazon) will work for most commercial and residential inflatable houses. For more detailed instructions on where to set up a bouncy house, check out my guide Places to Set Up a Bouncy House.
Just be sure not to let anyone enter the bouncy house too soon; you'll need to anchor it before you can use it. I like to store all the bouncy house accessories in a separate bin near the bouncy house in the garage, so now is the time to get everything ready.