How much equity do I need in my home to take out an Alliant HELOC? The amount of equity you currently have in your home will determine your Home Equity Line of Credit (HELOC) limit. You must retain at least 15% of the value of the equity in your home (sometimes referred to as a 85% LTV maximum). You can make a ballpark estimate of your HELOC maximum by calculating what 85% of your home’s value is, then subtracting your existing mortgage balance(s) from that number.