Note that you only need to repay the equity loan in full when you pay off your mortgage, sell your home or come to the end of your equity loan term. You can also choose to pay off your equity loan any time, in full or in 10% chunks before the end of the loan period.
In summary
The amount you borrow is a percentage of the value of your new home. The amount you pay back is the same percentage of the value of your home.
This means, if the value of your home rises, so does the amount you owe on your equity loan. It works both ways, so if the value of your home falls, the amount you owe on your loan falls too.