WASHINGTON — Montgomery County firefighters fought two separate fires Saturday that displaced residents in each dwelling.

A house fire on the 2800 block of Urbana Drive in Silver Spring, Maryland started when a window air conditioning unit in a second-floor bedroom caught fire. The unit fell to the ground and ignited the house’s siding. Thirty-five firefighters were on the scene, and one family of four adults was displaced. Officials estimated more than $35,000 in damage.

Later Saturday, firefighters were called to the 13700 block of Dowlais Drive in Rockville, Maryland, where the first and second floors of a two-story house were on fire. Sixty-five firefighters were on scene. Two adults, one child and a dog were displaced.

Montgomery County Fire and Rescue spokesman Pete Piringer said electrical wiring was the cause of the fire on Dowlais Drive, and damage is estimated at more than $400,000.