Originally Posted by dhays
As others have said. You negotiate and pay in Canadian currency.
Your bank will convert your US to CA at the time of the transaction. If you are concerned about the rising CDN, the buy some now as a hedge.
I was going to suggest that, but you have to be confident that you're going to spend the CDN before doing that. You don't want to be in the situation where you buy foreign currency and then end up having to convert it back. Maybe you get lucky on exchange rate fluctuations, but more likely you eat a couple of percent on the buy/sell spread. And you could get caught on the wrong side of the currency fluctuations as well...
Just keep the timeline between offer and closing short. Exchange rates in this case don't typically change that quickly. At least not in normal times.