patrick.net

Zillow was a good idea back in 2005, poorly implemented in my opinion. Redfin is much better, at least in the universe of sites offering free services. It has more accurate data, and none of that 'Zestimate' crap.

Zillow is based on public data, much of which is outdated or plain wrong. Also an area with a lot of sales get more of an accurate picture than an area with fewer sales. According to Zillow, just based on public facts and house with less square footage and on a smaller lot than mine 200 feet from a noisy major highway is more valuable then my house on a lightly traveled country road. Also many of there calculations are screwed up. I entered figures for a owner estimate on my house for improvements I've made and Zillow DEDUCTED that amount from the final estimated value. I've seen other times where it just added the amount to Zillows estimated value. To be done right, it should be a percentage of the cost of each improvement. For example you get back 65% to 75% of the money you invested into a bathroom remodel when you sell the house, 80% for a Kitchen, 85% for a deck addition, etc. Houses with more bedrooms are valued more than larger houses with less but bigger bedrooms. I guess it don't matter if the house's bedrooms are not much bigger than a closet, if you have 6 it more valuable then a house with 4 bedrooms that are overall more square footage.

Post I did on Zillow a while back for my own blog/site.

http://conejovalleyconnection.com/2010/08/05/la-and-ventura-zestimates-revealed/