According to calculations from the UK company Swift Direct Blinds, Kevin McCallister’s elaborate booby traps in Home Alone would have caused about $11,800 (£9000) worth of damage to his family home.

Among Kevin’s most memorable pranks? Smearing the basement stairs in tar, covering a room (and the bandit Harry) with glue and feathers, throwing paint cans down the second-floor staircase, and heating the main entrance’s doorknob with a charcoal grill starter.

Replacing that superheated doorknob would cost about $130; repairing the basement stairs would cost $910; cleaning up the glue and feathers would cost a whopping $3900; and redecorating the house after the multitude of damages would cost somewhere in the neighborhood of $4420.

Kevin’s other Rube Goldberg-esque traps (like making an iron fall from the laundry chute and breaking several shelves and Christmas ornaments) would make up the remaining $2340 worth of damage.

Swift Direct Blinds

Swift Direct Blinds

And that’s not even taking into account the cost of the medical treatments Harry and Marv, the not-so-nefarious Wet Bandits, would need after going through Kevin’s house of horrors (that is, if they hadn’t died already).

The lesson, which by all rights everyone should have learned after the first movie? Never leave Kevin McCallister to his own devices—the results are pricey for everyone involved. (And also consider investing in a more traditional security system).