Webuse our free mortgage calculator to get an estimate of your monthly mortgage payments, including principal and interest, taxes and insurance, pmi, and hoa. Webuse the mortgage calculator to get an estimate of your monthly mortgage payments. Use the home affordability calculator to help you. Webthis chapter explains fannie mae’s property assessment and valuation requirements, including documentation, appraisal and data collection requirements. Weboptions range from use of automated valuation models to validate the estimated property value, to collection of updated property data to confirm the model. Webhome value explorer ® (hve ®) is freddie mac’s automated valuation model (avm) that estimates the fair market value of properties in seconds.