House spirits, as you probably know, have a very different relationship with time from ours, and usually exist in a kind of floating dream-like observation. "Sleepy" might not be a bad word to describe it, though it does anthropomorphize something that is very much not anthro-. You almost don't want to say that the house spirit "saw" my stalker take the t-shirt, "saw" my subsequent befuddlement. It would almost be more accurate to say that because those events happened in the house, the house spirit couldn't not be aware of them: in a sense the resting house spirit is the observation ability of the house itself.
When did it fully "wake up?" Probably during the Boulder floods of 2013, in response to the insult the house experienced when the sewers backed up. That we took a long time to rebuild might explain its continued restlessness.
It remains active. I got home after midnight Monday night/Tuesday morning, and my wife sleepily told me that she'd awakened at some point to find all the covers thrown totally off the bed. Now, she's got a weird thermostat and sometimes gets hot for no reason at all and then kicks the covers off, but when that happens she always remembers doing so. Not this time. She was pretty puzzled.
But I know what's up. Definitely the house spirit. Hey, house spirit: I want my Ibex shirt back. I barely even got to wear it.