Do I owe departure tax on my principal residence in Canada if I emigrate but keep the house?

No. Canadian real estate is one of the categories specifically excluded from the departure-tax deemed disposition, so keeping your house in Canada when you emigrate doesn't itself trigger a deemed sale or a departure-tax bill on the property. Canada retains the right to tax the property directly if and when you eventually do sell it, so there's no need to tax it a second time just because you've become a non-resident.

That doesn't mean there's nothing to think about. Once you're a non-resident, an eventual sale of that property is subject to its own rules for non-resident sellers, separate from the departure-tax framework, and the principal residence exemption that sheltered gains while you lived in it works differently once you're no longer a Canadian resident using it as your home. The years you actually lived in it as your principal residence, versus the years you owned it as a non-resident, matter to how much of any eventual gain is sheltered.

Because the real complexity here shows up later, at the point of an eventual sale rather than at departure itself, it's worth getting advice on the future sale mechanics at the same time you're planning your move, not just on the departure-tax question in isolation.