Under fair market value sales affect on appraisals

[Bruce C.]

Hello. My name is Bruce. New to biggerpockets. Thanks to everyone so much for all the info provided at hand. Im curious if anyone can help me understand how under market value sales in a neighborhood can affect the appraisal of ones home. Or if this is even a factor appraisers take into consideration when determining the value of ones home. I apologize for the lack of understanding. Were working to refi our home to eliminate pmi and get out of our fha loan into a convention loan as well as open a heloc to assist in the purchase our first investment property. Thank you for any thoughts on this.