Be careful when signing up for a home equity loan or line of credit - the disclosed APR does not reflect the total fees that are associated with the loan, such as closing costs and others. Do not forget to compare this cost, as well as the APR, across multiple lenders.
The vast majority of home equity plans will utilize variable interest rates instead of fixed. A variable rate reflects the current prices of a publically available index, like the prime rate, or the U.S. Treasury Bill rate, and the rate of your loan will oscillate accordingly.
Generally a lender will offer a discounted introductory rate, often referred to as a "teaser rate". Take caution - these rates can sometimes fluctuate unless it is stated that there is a fixed rate. Sometimes the lender will give you a great introductory rate that is variable and can change with time to a rate much higher than you originally agreed to.
Since the rate is linked to an index rate, find out which one it is and how much their margin is. Some companies will have a cap on how much your rate can vary within a particular period of time.