It's a loan that's linked to the rise and fall in the value of your home. If you take a 20% equity loan for example, the amount you owe will always represent 20% of the property's value.
You won't be charged loan fees on the equity loan for the first five years of owning your home.
After five years you will be required to pay an interest fee of 1.75% of the amount of your Help to Buy shared equity loan at the time you purchased your property, rising each year after that by the increase (if any) in the Retail Prices Index (RPI) plus 1%.
The loan itself is repayable after 25 years or on the sale of the property if earlier.