It's unfortunate that "fixed" doesn't mean what it does with US mortgages. Here, a fixed rate mortgage is fixed for the life of the mortgage, typically 30 years

It's unfortunate that "fixed" doesn't mean what it does with US mortgages. Here, a fixed rate mortgage is fixed for the life of the mortgage, typically 30 years or at 15 if you opt for a higher payment. What you're describing is known here as an ARM (Adjustable Rate Mortgage) and they are a very scary thing because you never know for sure what the macro economic situation will look like.