PMI or Private Mortgage Insurance is normally required when you buy a house with less than 20% down. Mortgage insurance is a type of guarantee that helps protect lenders against the costs of foreclosure. This insurance protection is provided by private mortgage-insurance companies. It enables lenders to accept lower down payments than they would normally accept. In effect, mortgage insurance provides what the equity of a higher down payment would provide to cover a lender's losses in the unfortunate event of foreclosure. Therefore, without mortgage insurance, you might not be able to buy a home without a 20% down payment.

The cost of PMI increases as your down payment decreases. Example: The cost of PMI on a 10% down payment is less than the cost of PMI on a 5% down payment. Your PMI premium is normally added to your monthly mortgage payment.

The decision on when to cancel the private insurance coverage does not depend solely on the degree of your equity in the home. The final say on terminating a private mortgage-insurance policy is reserved jointly for the lender and any investor who may have purchased an interest in the mortgage. However, in most cases, the lender will allow cancellation of mortgage insurance when the loan is paid down to 80% of the original property value. Some lenders may require that you pay PMI for one or two years before you may apply to remove it.