Last year Jaco Joubert set out to estimate the number of condos in Toronto that are potentially sitting vacant. It was a response to the ongoing speculation that too many investor-owned condos are sitting empty across the city and thereby limiting the supply of housing.

To accomplish this, he photographed 15 different buildings at night (and at different times of the year) and monitored who had their lights on. He then turned these photographs into heat maps and compared the lighting pattern to the floor plans of each building in order to determine the unit demising.

This month Jaco published his findings. All in all, he estimates that he surveyed some 1,362 units. And of these units, 76 are believed to be vacant (when in doubt he erred on the side of occupied). So a vacancy of 5.6%. Is that more or less than what you were expecting?

Now, the buildings he "surveyed" are all located downtown and they are all roughly the same vintage. So you could easily argue that these aren't necessarily representative of the city's broader condo stock, assuming that's where you want to take this. Still, an interesting study.