How can I get Zillow to change it's zestimate on my home?

"you have my home's square footage way off, like 400 sq. ft. less than it really is! There's a home with the exact same floor plan for sale down the street with the sale price and info appearing on your website. Only my home is WAY nicer and offers several features that have been added in recent years"

If the square footage is off, edit it, and the estimates will adjust slowly over about a 2 month period.  Zillow pay's 3rd party data collection companies that collect public records data for other entities, such as city planning departments, for the data they show.  If it is wrong here, flag it, so that the data collection company can be made aware of their errors.  On the other hand, if it is wrong here and copied correctly, then it could be wrong at the county and thousands of other locations as well. 

Were permits pulled for all those "improvements" done over the years?  If not, it doesn't increase value, it "lowers" value as it will all have to be "ripped out" and redone with proper permits in order to get an occupancy permit after purchase.

"Killing" your "value"?  You have to be kidding!   The 70% confidence interval posted for the "estimate" is over +/- 42%!  The quarterly tolerance analysis for Ohio indicates 17.8% of the sales for the 4th quarter of 2012 were NOT within +/- 20% of the prior Zestimate.  and 48.4% of the sales in that quarter were NOT within +/- 10% of the prior Zestimate.  And 50% of the sales in that quarter were NOT within +/- 9.5% of the prior Zestimate.

The only thing "guaranteed" about the Zestimate, is that it is NOT the present market value of the house.  It is only a "starting point" for "further evaluation".  See "what is a Zestimate" FAQ.

It is 100% illegal for an Appraiser to use Zillow's data and estimates in any manner.  If anyone has any "evidence" that an appraiser did that rather than using an AVM from Core Logic or other "subscription" service, they need to report it to the State as well as to Zillow so that the Appraiser can lose their license as well as be sued for violating the terms of use.

There are thousands of AVM's.  Zillow has less than 10% of the market share.  They have absolutely no influence of any kind on what sells for what prices.  Even if people refuse to buy citing some random "estimate", it is the "competition" of what else is offered for sale that determines what they will really pay, or if they will live in homeless shelters or in street gutters for the rest of their lives.

If you don't like Zillow's free AVM, there are dozens of other free ones that are checked by buyers at least as frequently as Zillow's.  But so far, I have found no tolerance data posted for the other AVM's.  It appears that most have a wider tolerance margin, not narrower.  eppraisal.com tends to run high, so if you get an offer citing a Zestimate, counter with an estimate from eppraisal.  Or better yet, just tell them to go buy something else since they obviously don't want yours.  Let them try to argue someone else down instead.

I have posted this week the identical complaint as you. In my opinion, Zillow may take retaliation for your message posting by reducing the value more. Again look at 9727 SW 53rd Terr Ocala and compare it with the homes across the street. You think your home was wrongly evaluated; check mine. But, since I posted my complaint in this advice column, it's value in 30 days was reduced almost twice of that of less desirable homes. You see, according to Zillow, three homes A, B. and C where each progressively larger, and more rooms, garages and on the same block, will
be valued in such a way that the largest (C in this case) will be judged by Zillow to have less value than perhaps both A and B. If it seems incredible or impossible chech my block in Ocala, Florida. More of my posting is seen earlier this week if you want to check those. I have yet to get a realistic explanation from anyone. 

I strongly agree with you...Zillow seems to be unreachable and not accountable. They have an obligation to immediately update values when they assign geographic locations to homes not even remotely near their actual location. In essence, they are taking thousands of dollars away from a home seller due to their total incompetence. I  recommend people contact the BBB, their congressional office and state attorney generals office and lodge formal complaints. It's one thing to make a mistake but another to not correct it and provide some canned response not reflective of reality. They have self annointed themselves as some accurate value estimator which may be the case WHEN THEY HAVE THEIR FACTS STRAIGHT, BUT CLEARLY THEY ARE MAKING TOO MANT MISTAKES AND UNFAIRLY CREATING VALUES THAT COST IMPACTED HOMEOWNERS TENS OF THOUSANDS. When you can't find a way to contact them directly, that usually means they are not at all interested in accountability for their mistakes or addressing them. Better yet, contact your local media outlets...that will get their attention!

I'm not a fan of Zillow's "valuations" as they are so inaccurate.  Fortunately, even if your home is for sale a low valuation does not hurt.  Very few buyers use Zillow, and those who do quickly realize that Zestimates result from a rough, rough calculation, and they aren't even as accurate as property tax valuations, which also aren't very accurate.

I am a flat fee MLS listing Broker member of the Columbus/Central Ohio Multiple Listing Service (BuySelf Realty), and our sellers' homes often sell for substantially more than the Zestimate.  If you'd like examples, contact me.

So my advice to everyone is: Use the zestimate only for entertainment purposes.  Fortunately, no professionals use the zestimate, so it doesn't impact a sale or potential sale in any way, other than sometimes getting a chuckle.  Thanks and Good Luck.