Most HELOC rates are tied to the prime rate as an index.
	Some are based on the existing prime rate plus an additional margin.
	If prime increases, your HELOC increases.
	Some HELOCs have an introductory teaser rate which entitles you to a lower rate for an introductory period only
	Most HELOCs offer interest only payments.

WARNING!  Interest only means just that, interest only!  If you have short term needs for the money and will pay it off soon, all will be fine.  But, if you intend to pay on the HELOC for a long period of time, and you do not make extra payments towards the principle balance, you will find out in years to come that you still owe the exact balance that you began with.  Principle and interest loans pay, principle + interest.  If your HELOC is interest only, you only pay interest and defer the principle balance payments till later.

Most HELOCs have an initial draw period.  This draw period allows you to use and pay back some or all of the balance and draw again upon your balance limits.  Some initial draw periods are 10 years or 15 years.  After the initial draw period, the loan ‘shuts off’ and no longer allows you to draw another payment.  It converts to fully amortizing loan.  This means that you have a set period of time in which the loan must be repaid in full.  Most HELOCs will close and amortize over a period of 10-15 years.  It will amortize still based on the interest formula that it started.  If it started at an index of prime + 2%, and 10 years later your loan shuts off for re-pay and prime is now 6%, your rate will be 6% + 2%=8%.  Your payments will amortize at 8% based on a pay off of the stated 10 years.  If the prime rate goes up, your payment will go up accordingly and it will re-calculate so that your loan still will be paid off by you in the remaining years of the loan.