You want to know what your home is worth but you are not ready to sell. You may be considering whether to upgrade your kitchen or move. You may be completing a financial statement for the bank. Or, you may just be curious. But, you do not know a Realtor and do not want to go to a lot of trouble. Automated Valuation Models (AVMs) produce answers which may be useful to you.
AVMs use tax records which include information such as location, square feet, number of bedrooms and bathrooms, and property tax valuations. They also use sales prices where available.
Nationally, AVMs are most accurate where the creator of the model has the most information, where home prices are lower, and in newer subdivisions where few homes have been updated. They are less accurate where less information is available, more expensive or custom homes are involved, and in older neighborhoods where significant differences exist because of remodeling and updating.
Historically, AVMs were used by industry insiders such as mortgage companies. However, more recently some national home search sites provide these tools as part of their effort to supply useful information to consumers and leads to Realtors. The most famous sites are Zillow and Trulia. However, if you search on the internet, there are other sites that advertise their services. I found a product from Chase using an internet search. I have paid for a proprietary AVM for over a year. And, because I am a Realtor, I have access to another AVM provided by the National Association of Realtors.
Of primary importance with these products is accuracy. In my review, Zillow was most transparent about accuracy. See their comments here. The “Los Angeles Times” recently produced an article discussing the issues with accuracy at Zillow. The other AVMs use price ranges or disclaimers or both. Homes in Texas present a unique issue in that the sales price of a home is not public information. So, while Realtors have access to this information through the MLS, the public is generally not aware of sales prices. This also means the local taxing authorities do not have access to this information and may not have access to information on remodeling if the remodeling is not done in a taxing authority where building permits may not be required (e.g., outside a city limit.) So, for example, the taxing authorities may not be aware of a pool or a completely remodeled kitchen and bathrooms. Both taxing authorities and the AVMs may become aware of sales prices and updating if the owners or Realtors input or provide the information to the AVM (e.g., Zillow or the Harris County Appraisal District – HCAD.) However, most owners and Realtors do not provide this information. As a result, the accuracy of AVMs is compromised. In the Zillow accuracy disclosure, Zillow indicates their accuracy for Houston is one star out of four stars.
However, even with those limitations, based on my testing for my own home and recent transactions, AVMs may provide useful information, especially if taken in combination with information from other AVMs and HCAD. And, it may be fun or interesting to search these sites and others for the values. I have not identified specific AVM sites with my results because they all can be close or nowhere near right depending on the properties. My home is more difficult to value for an AVM, even if it were not in Texas, because it is an older home in a 1950s neighborhood that has new houses, extensively remodeled homes and homes that have had no major work since the 1950s. My results were:
Price per HCAD is within 20% of my market value.
Site 1 produced a range that was 19% below to 9% above my market value.
Site 2 produced a price that was more than 40% below market.
Site 3 produced a price that was 5% below market.
Site 4 produced a range that was 30% below market to 6% below market.
Site 5 produced a range that was 14% below to 11% below market.
I also looked back at my most recent transactions representing buyers and sellers. Using one of the AVMs, the actual sales price differed from the value estimated by from 14.8% lower to 27.0% higher, averaging a 12.8% difference.
Of course, these sites should not be used if you plan to sell your home. The best answer if you plan to sell your home is to find a Realtor who can use information from the MLS about prior sales and insight into the current market to help you come to an accurate estimate of the value. I would be happy to provide valuation information for your home without any obligation.