Originally posted by @Brian Cardwell:
I think i may not be being clear. I will try to keep it simple.
Basic facts :
Primary mortgage. Equals 200k
Salary equals 5k.
Total monthly expenses equals 3k
HELOC equals 20k in second position
So lets start this off.
First let's pull 10k out of the HELOC and put it on the principle of the 1st mortgage.
First mortgage = 190k
Heloc= 10k balance
Month 1
Then let's put your entire paycheck in the HELOC acct. This accomplishes paying the minimum payment on the HELOC.
HELOC= 5k balance
Now let's pay your expenses from your HELOC.
HELOC = 8k balance 5k(balance)+3k(expenses)
Month 1 balance
Primary mortgage 190k owed
HELOC 8k owed
Total debt 198k owed
Month 2
Put the entire paycheck in the HELOC
HELOC balance 3k owed (8k-5k)
Pay expenses of 3k
Mortgage Balance 190k
HELOC balance of 6k owed (3k+3k)
Total debt is 196k
Month 3
Pay expenses 3k
HELOC =9k
Put entire check in the HELOC
HELOC = 4k
Mortgage Balance owed 190k
HELOC = 4k
Total owed 194k
Rinse and repeat......
In month 5 your heloc balance owed will be 0.
....
And at the end of each month, your total owed, 1st mortgage plus HELOC, totals exactly what it would total if you simply paid an extra $2000 on principal of the 1st mortgage, without taking out the HELOC.
Assuming the spreadsheet that @DavidDachtara posted is a correct representation of "velocity banking," the strategy does work, in that it can pay your mortgage down faster. However, it does not pay the mortgage down with a lower interest expense than simply making monthly extra payments on principal equivalent to the HELOC payments would. It pays it faster than monthly extra payments on principal, but at a greater interest cost.
To use the typical advertised example of 7 years, I calculated the default loan in David's spreadsheet, $200,000 at 5% on a 30-year loan, and the default HELOC rate in David's spreadsheet, 7.5%. With those numbers, and with the goal of paying the mortgage down in exactly 7 years, the HELOC payment on principal would be $22,000 a year, repaid at $1908.66/month (except the last payment, somewhat less). The interest on the 1st plus the interest on the HELOC over the 7 years totals $46,486.
The alternate payment, $22,000 divided by 12, is $1833.33 (but a smaller last extra principal payment). Paying this extra on principal monthly pays off the mortgage in 7 years and 8 months with a total interest cost of $44,921.
The HELOC method ends up costing $1565 more in total interest. And I didn't even include the other costs of the HELOC: Closing costs and annual account maintenance fees. Based on a HELOC I know of, that can total, for 7 years, about $700. That would bring the excess cost of using the HELOC rather than making an equivalent monthly extra payment on principal to $2533.
Maybe the numbers work out differently if you do the method of a massive payment on the 1st from the HELOC every six or so months, with monthly payment of your entire paycheck on the HELOC, and payment all your living expenses from the HELOC, and rinse and repeat; perhaps there's some difference in the amortization of a few dollars. But I can't see it actually making up for the extra interest (and fees) you pay on the HELOC, which you don't have to pay if you simply make the extra payment on principal from your paycheck.
As for the statement that what you pay from your paycheck is gone, and the HELOC instead makes money available for emergencies or investing as you recycle paying it off every so many months, well, there's a simple remedy for that: Take out the HELOC and just do not use it except for those emergencies or investments. That way, if it's unused, you don't have the interest cost, at least.
But assuming David's spreadsheet is doing the numbers right for velocity banking, it does not cost less than simply making equivalent extra payments on principal, though it can pay off a mortgage in fewer months.