I know the gist of a HELOC but I can't seems to find an answer to this.

This bank who is also my mortgage lender is now offering a HELOC of 3.25%.

https://www.thirdfederal.com/My mortgage is currently @ 3.19% ARM that's has 3 years left before it adjust.

So lets say i get approved for a $100k HELOC at the current 3.24 rate.

If I decided to withdraw the entire $100k right away, am I fixed with that 3.24 rate for the duration of that $100k or does the rate fluctuate as long as I have the original $100k balance.

Thank You