Chunking sounds simple when you hear it in a video. Pull a lump of money off your line of credit, throw it at the mortgage principal, then let your paychecks refill the line. Repeat until the mortgage is gone years early.
Before you do it, run the naive math, because the naive math says don't. Say your mortgage is at 6.5% and your HELOC is at 8%. Move $10,000 from one to the other and you've traded $650 a year in interest for $800. If that chunk just sat on the line for a year, you'd be down $150 for your trouble. Anyone who tells you chunking wins on rate alone is selling something.
The trade works, when it works, because the line doesn't sit still. Your income runs through it. Park a $4,000 paycheck against that $10,000 chunk and the balance drops to $6,000 the day it lands. Bills flow out over the month, the balance drifts up, the next paycheck knocks it back down. The average balance on the line ends up well under the full $10,000, so the real interest cost comes in under that scary $800. Meanwhile the mortgage side is clean. $10,000 of principal is gone for good, and every payment after that pushes a little further into principal on the amortization schedule than it would have.
The honest test is your monthly cash flow. If you clear $1,500 a month after everything, a $10,000 chunk is off the line in about seven months and the math tilts your way. If you clear $200, the chunk lingers for years at the higher rate and the naive math wins. Chunk what your cash flow can bury in a handful of months. Not more.
HELOC rates float. The 8% in this example can become 9% without asking your permission, so leave room in the plan for that. And keep a cushion of available credit for real emergencies, because a maxed-out line is just another payment.
The full sequence, parking plus chunking through a whole month, is laid out on the How It Works page. If you'd rather back up and look at the whole household first, the broader money-flow picture is at Oregon Cash Flow Pro.