Sit or stand quietly and still , at dusk is always best, and be ready for a surprise. As they fly by echo-location and are astonishingly precise they'll fly close by your head as they hunt moths. Your granddaughter is certain to be able to hear them locating by their squeaks ,too, because children and young women can still hear that high frequency sound.
At first they may prove quite difficult to see, but have her be patient because her eyes will gradually adjust.
And, indeed, they may be roosting or living in your house.They are tiny and easily fly through gaps under the eaves. A roofspace is cool and dark,and the construction inside provides convenient roosting perches, which they think ideal. (Not just the roof:we found some had taken to roosting in the open wardrobe of a back bedroom, where we'd left a top window open LOL.)What's more, the lights of the house attract moths, so they've a ready meal being delivered to their 'doorstep'! If they settle you're soon know. They can be surprisingly noisy, scrabbling about up there. They're protected , as Lankeela says.