[Hondaracer]

Scotia and some other banks kind of have this "all in one" account where, as you pay down your mortgage, that amount is now available to you in your HELOC automatically

However, as Gerbs said above, the rate you get with the HELOC is worse than the mortgage rate obviously so upon renewal etc. its probably in your best interest to add to your mortgage as opposed to getting a bigger HELOC if you're actually going to use those funds