Hello Jas888, I live in Shadow Hills, very close to your property. I can't tell you the amount of increase per year over the next or 3-5 years, but what I can say is..... Zillow is wrong on value... keep in mind they go off what has sold in the area and average it out. So they compare foreclosures, all cash sales, property that needs to be rehab, short sales and give you an estimated value. This is not how you determine value. I can say the average 3 bed 2 bath in Sunland starts at $340k and goes up from there. Have I seen homes for sale in Sunland for high 3's low 4's, yes. Keep in mind if you owe 390k then you would have to sell for close to $420k to walk away with a little bit of money in your pocket, once you factor in closing costs and agents commissions. Also the closer you are to the mountains or Tujunga the higher your value could be.
You will never know what a buyer is willing to pay for your property or how much your property could sell for unless you have an agent come out and give you real comps on your property.