How a refinance gives you equity
When you refinance, you break your current mortgage and replace it with a new one for a larger amount, up to 80% of your home's appraised value at a prime lender. Banks can't lend above 80% without mortgage insurance (Bank Act s. 418), and insurance isn't available on an ordinary equity take-out refinance (the only insured refinance is a narrow program for adding a secondary suite), so 80% is the ceiling. The new mortgage pays off the old balance, and the extra is yours as a lump sum. Because it's a mortgage, you get a mortgage rate, which is lower than almost any other way to borrow.
The catch is timing. If you refinance in the middle of a term, you'll pay a break penalty on the old mortgage — three months' interest on a variable, or the potentially much larger IRD on a fixed (estimate yours with our penalty calculator). And if your current rate is well below today's rates, refinancing means giving up that cheap money on your entire balance, not just the new portion. That's the single biggest reason people choose a HELOC instead.