I have found the opposite to be true - Zillow lower valuation than Redfin. Take the average.
Both showing the same value for mine in SF mid peninsula.
At Seattle eastside, Zillow estimate is usually 10% higher than Redfin. Redfin is closer but tends to trail the current fast trend.
Frankly none.
Better accuracy is to look at homes that have *sold* recently that are comparable to your place. Both websites show that information.
This. Redfin shows which 6 homes it looked to estimate the value ( under similar sold homes ) if you think they are really similar to your home then Redfin estimate would be accurate. If not then it will be off
Redfin has far better algorithm that works for most areas..
I like using redfin map of what sold in the last month. It's under the option a tab.
Redfin hans down, zillow misses a lot of data
It is a hit or miss at both. I own two houses that are just across the street. I bought one through Redfin and for that Redfin shows higher value than Zillow. I rent out the other house via Zillow and for that, Zillow shows higher and more realistic value compared to Redfin (even though Redfin has sold a lot of homes similar to my rental). So... it depends on the data points they have for the house and when they care to apply those data points. Some estimates are more accurate than others for both.
Redfin is more accurate for my house. I think Zillow gets confused because I have an average house in a neighborhood with a lot of totally ridiculous mansions.